Himax - Solar Will Be Cheapest
by Emma Foehringer Merchant
February 02, 2021

With President Joe Biden in the White House, ink drying on a spate of new climate-focused executive orders and an extension of the federal Investment Tax Credit on the books, the immediate future looks relatively rosy for solar.

The U.S. Energy Information Administration anticipates that renewables will be the fastest-growing source of electricity through midcentury. While solar accounted for about 15 percent of renewable electricity generation in the U.S. in 2020, according to EIA, that will increase to nearly 50 percent by 2050. And solar will be the cheapest form of electricity across the United States by 2030, according to a recently released Wood Mackenzie report. The consultancy expects solar costs to decline 15 to 25 percent over the next ten years.

In a recent series for Squared, I cataloged some of the technological innovations that could define the next decade for solar. Here, I’ll dig into the macro trends Wood Mackenzie analysts expect to drive the resource’s next decade.

Costs will continue falling through 2030

In 2011, the Department of Energy launched its SunShot initiative, modeled after the moonshot effort of the mid-twentieth century, to “reduce the costs of solar energy and reestablish U.S. global leadership” in solar. A decade later, the U.S. has accomplished at least one of those goals; three years before DOE had targeted, SunShot successfully lowered utility-scale solar prices to its goal of $1 per watt.

Cost declines have been the most integral tool in allowing large-scale solar to grow. Worldwide, solar system prices fell by more than 80 percent from 2000 to 2010, according to WoodMac’s analysis.

Meanwhile, installations grew.

Although SunShot floundered under President Trump, prices kept falling in the U.S. Overall, prices for the engineering, procurement and construction of large-scale solar systems fell by more than 30 percent during Trump’s presidency, according to WoodMac.

That happened amid uncertain policy; the Biden administration’s support should provide more stability to the industry. WoodMac expects that costs will continue dropping. Solar is already competitive in a swath of the West and much of the Southeast. That trend will make its way into more of the Northeast by 2021 and the Mountain West by 2022. It will come for the frigid northern Midwest by mid-decade.

By 2030, solar will be the lowest-cost source of generation across the entire U.S.

Corporate purchases

Solar power’s downward price trajectory has caught the eye of corporate buyers. That’s a big market for renewables: Commercial and industrial electricity consumption accounted for more than 60 percent of electricity sales in 2019. And large companies have already become some of the most significant buyers of renewable electricity. In Q4 of 2020, these buyers accounted for 20 percent of the contracted pipeline for large-scale solar. In 2019, commercial solar installations grew 10 percent over the previous year, according to tracking from the Solar Energy Industries Association.

Analysts expect continued declines in the levelized cost of solar energy to strengthen that demand, which in turn has significant potential to reshape energy markets. After signing onto a growing slate of contracts tied to renewables projects, many companies are now looking for even more control of their electricity supply. A recent statement spearheaded by the Renewable Energy Buyers Alliance, a group with members including Facebook and General Motors, lays out the energy policies corporations hope to see advanced under the Biden-Harris administration. Their asks include expanding wholesale electricity markets to smooth the trading of electrons across regions. Some companies, such as Google, have already joined regional transmission organizations to gain more leverage in determining how those markets function.

The ability for solar to compete on price alone means that more merchant-centric projects could also be on the horizon, according to WoodMac. Most solar projects in the United States have relied on long-term, contracted revenue streams that last for at least a couple of decades. But as investors have become increasingly comfortable — perhaps too comfortable, some might say — with the structure of solar deals and the returns associated with the projects, shorter contracts have become more common.

“There’s definitely a lot of buzz in the market about the prospects of having merchant-based projects. But in the truest sense of the word, I don’t think there is a single [merchant solar] project yet,” said Ravi Manghani, WoodMac’s head of solar research. “Developers would need to come up with the right sort of hedging tools, whether these are physical tools like potentially storage, or financial tools, like hedges or insurance products. Those will have to become more commonplace as these projects start to be truly merchant.”

The role of storage and transmission

Cost declines have helped solar gain momentum. But overall, solar provided only about 2 percent of U.S. electricity in 2019. And if the resource is to grow significantly enough to meet clean energy mandates and climate goals set out by states and countries, it needs more support.

Energy storage is already being added to more utility-scale projects, and more projects are being designed to allow for its later addition, to help extend the hours in which solar projects can deliver electricity. Developers and asset owners such as Capital Dynamics have said storage is a consideration, if not the default, for every project.

“In the long run, as solar washes over the United States, storage follows along behind,” John Breckenridge, Capital Dynamics’ head of clean energy infrastructure, told Greentech Media this fall.

While storage will help balance uneven solar production, transmission is needed to carry it from where it’s most cost-effectively generated to where it’s most in demand.

Lack of transmission capacity has major potential to constrain solar growth, stymieing decarbonization efforts like those set out by the Biden-Harris administration. Already, experts and wonks are asking the new administration to confront that challenge. Clean energy groups supported by numerous past members of the Federal Energy Regulatory Commission highlighted that need in a report released this week.

“There is no climate plan that is serious if it does not anticipate a significant regional transmission upgrade,” said Pat Wood III, who served as FERC chair from 2001 to 2005, in an event spotlighting the report.

The administration appears to be paying attention to these issues already. An order President Biden signed this week urges the acceleration of federal permitting for transmission. And in a Wednesday Senate hearing on her nomination to head the Department of Energy, former Michigan Governor Jennifer Granholm named building out transmission to transport clean electricity as a “high priority” if she is confirmed.

“I’m very eager to work with FERC to get transmission lines established ASAP,” Granholm said Wednesday. “I feel like this is a conversation that’s been had for years, about having the right transmission lines in place to take power…(clean power especially) from places that are generating to the power and load centers.”

Aside from storage and transmission, which will make solar easier to use in more places and at more times of day, solar itself is becoming more efficient.

Bifacial solar, which allows for the absorption of sunlight on both sides of a panel, is perhaps the most significant solar technology improvement in recent years, or at least the one to become most mainstream. It’s already the default choice for numerous developers in the U.S.

The Section 201 exclusion that bifacial solar enjoyed for a time aided that development, though the exclusion was ultimately reversed by the Trump administration (solar groups are challenging the verdict).

Despite the policy confusion surrounding tariffs, analysts at Wood Mackenzie name bifacial among just a few technological innovations that are likely to boost solar production and help cut costs in the coming years. (Others are larger panels and wafer sizes, as I cover here, as well as improvements in solar trackers). Commercial bifacial solar modules offer production gains of 7 to 8 percent while costing not much more than single-sided panels. Analysts expect “the next decade will be marked by steady technological improvement along the entire solar value chain.”

“Every little improvement in generation or production means the capacity factor continues to go up, and that has direct implications in terms of the levelized cost,” said WoodMac’s Manghani.

Himax - PORTABLE LIPO CHARGING STATION

PORTABLE LIPO CHARGING STATION

When I started this hobby the thing that shocked me the most was how short flight times were.

5 minutes??? Sometimes more. Sometimes less.

To make matters worse, most people drive to a park or a field where they don’t have access to electricity to recharge their batteries.

Yes, you can buy a couple dozen batteries so you can get a couple hours of flying in. But what many people do is they make portable charging stations so they can stay out in the field.

Car Batteries

A lot of DC input lipo chargers will work at 12 V. For example, the SKYRC iMAX B6AC V2 has an input voltage range of 11 V to 18 V.

This means you can use a lead acid car battery to power you lipo charger.

And because a lot of us drive our cars to get to where we want to fly, this has become a popular solution for charging in the field.

There are a couple options here.

  • You can literally use your car battery.
  • You can buy a separate car battery that you only use for charging lipos.

Option 1 is cheap. The only thing you have to worry about is killing your battery. By charging your lipos with your car battery you are, of course, discharging your car battery. Discharge it too much and your car might not start.

Option 2 involves buying another car battery, which can cost a lot. They are also heavy to move around. And if you are going to be regularly discharging it you are going to need a battery charger to charge it back up.

There’s one more problem with using a car battery for this.

Car batteries were meant to start your car’s engine. This means it needs a whole lot of current for a short period of time. Starting your car only discharges about 3% of your battery. This is the opposite of what you need when charging lipos … a little bit of current for a long time.

More on this in the next section.

Deep Cycle / Marine Batteries

As I mentioned above, car batteries aren’t designed to be discharged all the way and then charged back up.

Because of this a better solution would be to use a deep cycle batteries. Deep cycle batteries are designed with thicker lead plates that allow it to be fully discharged and fully charged for many cycles. This is ideal for field charging lipo batteries.

These are sometimes called marine batteries because they are used for things like trolling motors.

High Capacity Lipo Batteries

Deep-cycle lead acid batteries aren’t the only type of batteries that are made to repeatedly go through a charge-discharge cycle. Lipo batteries like we use on quadcopters are designed to do that, too.

This means they would be perfect for charging in the field.

The 2 things you need to keep in mind if you go this route would be 1) input voltage and 2) capacity. If you need a refresher on what those terms mean, check out my lipo battery guide here.

For input voltage, I would recommend using a 4s lipo for most DC chargers. The nominal voltage of a 4s battery is 14.8 V and this puts you right in the middle of the voltage input range for most chargers.

For lipo capacity, I would recommend the biggest you can afford. The higher the capacity, the more times you are going to be able to use it to charge in the field. This battery is 16,000 mAh.

The great thing about this solution is that you don’t have to buy an extra charger like you do with a lead acid battery. You can use the same charger that you would use for your quad batteries.

(One caveat with this … Some of these bigger batteries use XT90 connectors while smaller capacity batteries usually use a smaller connector, like an XT60. Again.)

Portable Generator

portable generator for lipos
Why use a battery when you can make the electricity yourself?

There are a number of advantages to using a generator.

  • You don’t need to worry about capacity. Most generators will be able to provide more than enough energy to parallel charge multiple lipos.
  • Most generators have both an standard AC output and a 12 V DC output.  This means you have more options for what charger you can use.
  • You don’t have to worry about charging up yet another battery.  All you have to do is fill it up with gas.
  • Generators can be used for all sorts of other things: in emergencies if your electricity goes out, if you go camping and want to be able to do things like make coffee in the morning, etc.

There are some disadvantages, of course. They will be noisier than the other options (although not as noisy as you would expect) and they will be more costly. But other than that, they are a good option.

Find a field with electricity

The last option is maybe the best option if it is available. Find a place to fly that has electricity available. Some RC clubs may have fields that have electricity available.  Or try to find a park that has publicly available outlets.

Conclusion

I’m sure there are other options that people have come up with for charging your lipos in the field.  It’s a pretty common problem.  Let me know in the comments if you’ve tried anything else.

Himax - Battery-Bms

Battery-Bms

The power output depends on the battery, and the battery management system (BMS) is the core of it. It is a system for monitoring and managing the battery. It controls the charge and discharge of the battery by collecting and calculating parameters such as voltage, current, temperature, and SOC. The process, the management system that realizes the protection of the battery and improves the overall performance of the battery is an important link between the battery and the battery application equipment.

BMS mainly includes three parts: hardware, bottom layer software, and application layer software.

The hardware of the battery management system (BMS)

1. Architecture

The topology of Battery Management System(BMS) hardware is divided into two types: centralized and distributed.

(1) The centralized type

The centralized type is to concentrate all the electrical components into a large board, the sampling chip channel utilization is the highest and the daisy chain communication can be adopted between the sampling chip and the main chip, the circuit design is relatively simple, the product cost is greatly reduced, but All the collection wiring harnesses will be connected to the mainboard, which poses a greater challenge to the security of the BMS, and there may also be problems in the stability of the daisy chain communication. It is more suitable for occasions where the battery pack capacity is relatively small and the module and battery pack types are relatively fixed.

(2) The Distributed type

Distributed includes a mainboard and a slave board. It is possible that a battery module is equipped with a slave board. The disadvantage of this design is that if the number of battery modules is less than 12, the sampling channel will be wasted (generally there are 12 sampling chips. Channel), or 2-3 slave boards to collect all battery modules. This structure has multiple sampling chips in one slave board. The advantages are high channel utilization, cost-saving, flexibility in system configuration, and adaptation to different capacities. Modules and battery packs of different specifications and types.

2. Function

The hardware design and specific selection should be combined with the functional requirements of the vehicle and battery system. The general functions mainly include collection functions (such as voltage, current, and temperature collection), charging port detection (CC and CC2), and charging wake-up (CP and A+) ), relay control and status diagnosis, insulation detection, high voltage interlock, collision detection, CAN communication and data storage requirements.

(1) Main controller

Process the information reported from the controller and the high-voltage controller, and at the same time judge and control the battery operating status according to the reported information, realize the BMS-related control strategy, and make the corresponding fault diagnosis and processing.

(2) High voltage controller

Collect and report the total voltage and current information of the battery in real-time, and realize timely integration through its hardware circuit, and provide accurate data for the calculation of the state of charge (SOC) and the state of health (SOH) for the motherboard. Charge detection and insulation detection function.

(3) Slave controller

Real-time collection and reporting of battery cell voltage and temperature information, feedback of the SOH and SOC of each string of cells, and a passive equalization function, effectively ensuring the consistency of cells during power use.

(4) Sampling control harness

Provide hardware support for battery information collection and information interaction between controllers, and at the same time add redundant insurance function to each voltage sampling line, effectively avoid battery short circuit caused by wiring harness or management system.

3. Communication method

There are two ways to transfer information between the sampling chip and the main chip: CAN communication and daisy chain communication. CAN communication is the most stable. However, due to the high cost of power chips and isolation circuits, daisy chain communication is actually SPI communication. The cost is very low, and the stability is relatively poor. However, as the pressure on cost control is increasing, many manufacturers are shifting to the daisy chain mode. Generally, two or more daisy chains are used to enhance communication stability.

4. Structure

BMS(Battery Management System) hardware includes power supply IC, CPU, sampling IC, high-drive IC, other IC components, isolation transformer, RTC, EEPROM, CAN module, etc. The CPU is the core component, and the functions of different models are different, and the configuration of the AUTOSAR architecture is also different. Sampling IC manufacturers mainly include Linear Technology, Maxim, Texas Instruments, etc., including collecting cell voltage, module temperature, and peripheral configuration equalization circuits.

Bottom layer software

According to the AUTOSAR architecture, it is divided into many general functional modules, which reduces the dependence on hardware, and can realize the configuration of different hardware, while the application layer software changes little. The application layer and the bottom layer need to determine the RTE interface, and consider the flexibility of DEM (fault diagnosis event management), DCM (fault diagnosis communication management), FIM (function information management), and CAN communication reserved interfaces, which are configured by the application layer.

Application layer software of the BMS

The software architecture mainly includes high and low voltage management, charging management, state estimation, balance control, and fault management, etc.

1. High and low voltage management

Generally, when the power is on normally, the VCU will wake up the BMS through the hardwire or 12V of the CAN signal. After the BMS completes the self-check and enters the standby mode, the VCU sends the high-voltage command, and the BMS controls the closed relay to complete the high-voltage. When the power is off, the VCU sends a high-voltage command and then disconnects and wakes up 12V. It can be awakened by CP or A+ signal when the gun is plugged in in the power-off state.

2. Charging management

(1) Slow charge

Slow charging uses an AC charging station (or 220V power supply) to convert AC to DC to charge the battery through an on-board charger. The charging station specifications are generally 16A, 32A, and 64A, and it can also be charged through a household power supply. The BMS can be awakened by CC or CP signal, but it should be ensured that it can sleep normally after charging. The AC charging process is relatively simple, and it can be developed in accordance with the detailed regulations of the national standard.

(2) Fast charge

Fast charging is to charge the battery with DC output from the DC charging pile, which can achieve 1C or even higher rate charging. Generally, 80% of the power can be charged in 45 minutes. Wake up by the auxiliary power A+ signal of the charging pile, the fast charging process in the national standard is more complicated, and there are two versions of 2011 and 2015 at the same time, and the different understanding of the technical details of the charging pile manufacturer’s unclear technical details of the national standard process also causes the vehicle charging adaptability A great challenge, so fast charging adaptability is a key indicator to measure the performance of BMS products.

3. Estimation function

(1) the State Of Power

SOP (State Of Power) mainly obtains the available charge and discharge power of the current battery through the temperature and SOC lookup table. The VCU determines how the current vehicle is used according to the transmitted power value. It is necessary to consider both the ability to release the battery and the protection of the battery performance, such as a partial power limit before reaching the cut-off voltage. Of course, this will have a certain impact on the driving experience of the whole vehicle.

(2) state of health

SOH (state of health) mainly characterizes the current state of health of the battery, which is a value between 0-100%. It is generally believed that the battery can no longer be used after it is lower than 80%. It can be expressed by the change of battery capacity or internal resistance. When using the capacity, the actual capacity of the current battery is estimated through the battery operating process data, and the ratio of the rated capacity to the rated capacity is the SOH. Accurate SOH will improve the estimation accuracy of other modules when the battery decays.

(3) the State Of Charge

SOC (State Of Charge) belongs to the BMS core control algorithm, which characterizes the current remaining capacity state, mainly through the ampere-hour integration method and EKF (Extended Kalman Filter) algorithm, combined with correction strategies (such as open-circuit voltage correction, full charge correction, charging End correction, capacity correction under different temperatures and SOH, etc.). The ampere-hour integration method is relatively reliable under the condition of ensuring the accuracy of current acquisition, but the robustness is not strong. Because of the error accumulation, it must be combined with a correction strategy. The EKF has strong robustness, but the algorithm is more complex and difficult to implement. Domestic mainstream manufacturers generally can achieve accuracy within 6% at room temperature, and it is difficult to estimate high and low temperatures and battery attenuation.

(4) the State Of Energy

SOE (State Of Energy) algorithm manufacturers do not develop much now or use a simpler algorithm, look up the table to get the ratio of the remaining energy to the maximum available energy in the current state. This function is mainly used to estimate the remaining cruising range.

4. Fault diagnosis

According to the different performance of the battery, it is divided into different fault levels, and in the case of different fault levels, the BMS and VCU will take different treatment measures, warning, limiting power, or directly cutting off the high voltage. Failures include data collection and rationality failures, electrical failures (sensors and actuators), communication failures, and battery status failures.

5. Balance control

The equalization function is to eliminate the inconsistency of the battery cells generated during battery use. According to the shortboard effect of the barrel, the cells with the worst performance during charging and discharging first reach the cut-off condition, and the other cells have some capabilities. It is not released, causing battery waste.

Equalization includes active equalization and passive equalization. Active equalization is the transfer of energy from more monomers to fewer monomers, which will not cause energy loss, but the structure is complex, the cost is high, and the requirements for electrical components are relatively high. Relatively passive The balance structure is simple and the cost is much lower, but the energy will be dissipated and wasted in the form of heat. Generally, the maximum balance current is about 100mA. Now many manufacturers can achieve better balance effects using passive balance.

The BMS(Battery Management System) control method, as the central control idea of ​​the battery, directly affects the service life of the battery, the safe operation of the electric vehicle, and the performance of the entire vehicle. It has a significant impact on battery life and determines the future of new energy vehicles. A good battery management system will greatly promote the development of new energy vehicles.

Himax-Battery-12V-100ah

We have introduced voltage difference in battery packs and used it as an important criterion for measuring the quality of batteries.  At this time, we’ll review how to prevent voltage difference.

Match the cells

The best method in preventing cell voltage difference is to match the cells before the battery pack is assembled and to select the cells with the closest consistency for assembly. To put it simply, you match the batteries with the most similar specifications according to the configuration of the battery pack. There are many ways you can match the cells, but the most important elements to consider are the capacityinternal resistance, and voltage difference.

Ensure the quality

In Grepow, in addition to the conventional matching standards, we match the content of the battery cell’s production batchesmaterial batches and other standards to ensure that the quality of the battery packs we produce is the best. If the matching standard is stricter, then the probability of the battery cell voltage difference will be smaller. On the contrary, if the battery cell matching standard is less strict or if there is no matching at all, the probability of the cell voltage difference will be greater, and this will result in premature battery failure.

Use the BMS

In addition to the matching of cells before assembly, the use of a BMS balancing circuit is another great way to prevent voltage differences. At present, most BMSs on the market have charging balancing circuits.  The function of the balancing circuit is to equalize the voltage of each cell during the battery charging process and to keep the voltage of the cell as consistent as possible. If you are using a BMS to prevent voltage difference, ensure that the one you are using or selecting has the balancing feature.

Others

There are other possibilities that may also cause a voltage difference, such as cell damages and high-temperature storage.

Himax - LiFePO4-Battery
Note: Most of the information in this article comes from the Solar Living Sourcebook.

Sunlight doesn’t just power your solar panels – it heats your batteries. With fewer hours of sunlight per day, winter is the time of year when it’s most important to make sure the energy storage component of an off-grid solar system or grid-tie solar system with battery backup is working efficiently. Unfortunately for those of us in the northern U.S. and Canada, winter can bring extreme cold, creating the worst environmental conditions for those deep-cycle batteries.

But just because deep cycle solar batteries have a harder time in cold temperatures doesn’t mean you need to suffer through the winter with them. Learning a few simple tricks to keep solar batteries warm in winter will substantially improve their performance during the part of the year in which you rely on them most.

Note: Lithium-ion and sealed lead acid batteries (AGM and gel cell) fare much better in cold weather than traditional flooded lead acid batteries do, and are now so safe that they can – and should – be installed indoors. If you’ve got these batteries and they’re installed indoors, you should have nothing to worry about when it comes to cold weather!

Why Are Cold Temperatures Bad for Solar Batteries?

First let’s clarify that cold temperatures are actually good for batteries when it comes to holding a charge; a battery placed in a refrigerator will self-discharge more slowly than the same battery in a warmer setting (and in fact, some people keep their household AA and 9V batteries in the fridge). Where cold becomes a detriment to batteries is in situations where charging and discharging is frequent and the cycles are deep – like in a renewable energy system. This is because cold slows down the chemical reactions that take place inside a battery as it supplies electrical current. Colder temperatures reduce current, which in turn lowers energy storage capacity.

The cold weather problem is compounded with deep cycle batteries used for solar storage because cold weather usually coincides with storms or the shorter days of winter. In both cases, PV production is lower due to the reduced number of sun hours, and the loads in the house are often higher due to active heating.

How Cold is “Cold” When it Comes to Solar Batteries?

Most batteries are rated at 77°F (25°C), meaning their technical specs are based on how the battery’s cells perform at 77 degrees. As a rule of thumb, batteries lose about 10% of their rated capacity for every 15-20 degrees below 80°F as measured in the cells.

How Can You Keep Your Solar Batteries Warm?

The best way to keep deep cycle solar batteries warm is simply to give them shelter and insulation. Let’s look at how to best do this, depending on what kind of deep cycle batteries you have.

How to Keep Lithium-Ion Solar Batteries Warm in Winter

Lithium-ion solar batteries can be safely installed inside your house, meaning the “shelter” and “insulation” boxes are already checked and no additional action needs to be taken. However, if they are installed someplace where there’s a risk of freezing, special care must be taken because – while they can safely discharge in temperatures as low 0°F (-18°C) – lithium-ion batteries should never be charged in sub-freezing temperatures (below 32°F or 0°C).

Nearly all lithium-ion solar batteries on the market today include at least a basic built-in battery management system (BMS) that can activate an external heating source when ambient temperatures approach freezing, ensuring the battery’s environment stays warm enough for safe charging. A few more advanced lithium batteries even have internal heaters that are managed by their BMS.

How to Keep Flooded Lead Acid Solar Batteries Warm in Winter

Even though flooded – or “wet cell” – lead acid batteries can charge at lower temperatures than lithium-ion batteries (as low as -4°F or -20°C), they typically require the most attention in winter because they cannot be installed inside your house where temperatures are nicely regulated. (When in use these batteries release hydrogen gas – which is explosive at even a modest 4% concentration.)

Instead, flooded lead acid batteries should be kept inside a battery box or enclosure with 2″ holes near the top and bottom for ventilation. If the enclosure is inside an insulated garage or shed, they most likely won’t need any extra help staying warm. But if the enclosure itself is not in an insulated area, it should be “reinforced” with insulation and thermal mass to stabilize temperature swings. Because the batteries generate a bit of heat when they are charging, the insulation will keep that heat inside the enclosure, keeping the batteries warmer.

Simply get a sheet or two of rigid foam insulation from your local hardware store:

  • Do a quick internet search for the proper R-value of insulation you should buy based on where you’ll be using it
  • Insulation rated for use below grade use is best because it is moisture resistant

Diagram of an insulated outdoor enclosure for flooded lead acid batteries

Wires and cables pass through wall at bottom of battery box to prevent hydrogen from entering the house (hydrogen rises).

When installing insulation in your battery enclosure:

  • Cut the sheet to size with a circular saw, or score it with a utility knife and snap it over an edge for a clean cut
  • Leave an inch or two between the batteries and the insulation (and a little space between the batteries themselves) to allow air to circulate and keep temperatures as uniform as possible across all the batteries
  • Don’t cover your ventilation holes
  • Don’t permanently adhere the insulation to the enclosure – you’ll want to remove it when the weather warms up so the batteries don’t overheat in the summer

How to Keep AGM/Sealed Lead Acid Solar Batteries Warm in Winter

Like lithium-ion batteries, sealed lead acid batteries (AGM and gel cell) are safe enough to be installed indoors, giving you a huge leg up on temperature regulation. Also working in your favor is the fact that sealed battery cells freeze at lower temperatures than flooded/wet cells do. It’s best to check the manufacturer’s specs for your specific batteries regarding minimum charging and discharging temperatures. If your batteries are going to be exposed to temperatures lower than the minimums listed by the manufacturers, the same techniques suggested for lithium-ion and flooded lead acid batteries can be used to keep your sealed-cell batteries warm enough for safe use (insulated enclosure and a BMS/heater).

Tools and Tech to Help Keep Solar Batteries Healthy in Winter

MPPT Charge Control Technology

A charge controller with maximum power point tracking (MPPT) technology is probably already part of your battery-based solar system, but those short winter days are when you’ll be happiest to have it. MPPT solar charge controllers squeeze 15-30% more power out of a PV array on average than non-MPPT controllers by converting excess PV voltage into amperage. MPPT controllers perform best with cold PV modules and hungry batteries (sounds like winter conditions!), and can adjust the battery voltage based on battery temperature to help the cells reach 100% state of charge.

Battery Temperature Sensor

A battery temperature sensor can provide an early warning if battery temperatures drop below recommended levels. Some charge controllers will stop charging at certain low temperatures.

Battery Management Systems (BMS)

A battery management system includes functions beyond just temperature sensing, typically including features like voltage and depth of discharge at both the cell and battery bank level. This level of insight can help you identify problem areas in your battery bank, some of which may be cold-related.

A BMS is an absolute necessity for lithium-ion solar batteries (to prevent overcharging and thermal runaway), but most Li-ion batteries on the market today already have a BMS built in.

Battery Desulphators

These deep cycle battery maintenance tools simply connect to the battery terminals and then work automatically to remove lead sulphate buildup on the plates. Lead sulphate will otherwise build up on the plates over time, reducing a lead acid battery’s capacity and ultimately shortening its life. When you’re already contending with cold weather reducing battery capacity during the winter, you don’t need sulphate buildup compounding the problem.

Battery desulphator

Keep the Water Topped Off

It is important year-round to not let your flooded lead acid batteries go dry. In winter it’s especially critical to make sure there is plenty of water in them. A battery with low water levels is more likely to freeze.

Likewise, keep them charged up. The acid in the water prevents freezing, so a battery with a low charge is more likely to freeze than a charged one.

Adding More Battery Storage

Sometimes all the tricks in the book just aren’t enough to keep an older lead acid battery bank powerful enough to get you through the winter comfortably. Over time, batteries age and their capacity falls, and we add more electric loads to our homes. Sometimes the best way to combat the problem of cold weather limiting your batteries’ performance is to simply add capacity with a couple of new deep cycle lead acid batteries.

Winter or Not, Don’t Forget to Perform Regular Maintenance on Your Lead Acid Deep Cycle Batteries

For lithium-ion and sealed cell lead acid batteries (AGM and gel cell), a simple annual maintenance routine of cleaning the tops of the batteries with baking soda and water (then rinsing with water), and then cleaning/tightening the terminals is sufficient.

 

 

Himax - LiFePO4-Batteries

The 2020 coronavirus (COVID-19) outbreak has – to put it mildly – created a lot of uncertainty for people all around the world.

By now, hopefully you are doing your part to practice the self-quarantining or “social distancing” behaviors recommended by the World Health Organization to help slow the spread of this new and particularly hardy coronavirus and give the world’s various healthcare systems time and bandwidth to deal with the outbreak.

If so, you may be experiencing a new (or renewed) appreciation for the relative fragility of the production and delivery networks for food, water, energy, and information that aggregate to create the standard of living we’re used to here in the U.S. You may be considering the benefits of being self-sufficient in one or more of these areas, and wondering how realistic that would be. And you may be weighing whether the peace of mind that comes with self-reliance in times of social unrest is worth the effort and expense of actually becoming self-reliant.

Setting aside the healthcare system, which is facing real challenges in the coming weeks, we can say that, fortunately, American infrastructure has been largely able to cope with the changes in shopping behavior, remote working habits, and resource usage the new coronavirus has forced us to make. But if you have found yourself interested in moving toward self-sufficiency lately, know that you are not alone and you are not without trusted professionals to advise you about your options.

Lifeppo4-Battery-In-The-Industrial-Field

 

As a company born out of the “back-to-the-land” movement that spawned in part from the uncertainty and social anxiety of the 1960s and 1970s, Real Goods has always championed the merits of self-sufficiency and facilitated making it available to anyone who wants to achieve it. From this position, we think it’s worth noting a few things:

We should be grateful that most of our resource infrastructure – power, water, food production, Internet – has been able to handle the shifting demands the COVID-19 pandemic has placed on it.
Ideas like self-isolation, social distancing, and disaster preparedness are not new. For plenty of folks, these are – and have been for decades – lifestyle choices. They are things that come, to varying degrees, with the decision to live “off the grid”.
Moving toward self-sufficiency does not have to be an all-or-nothing endeavor. In fact, we don’t recommend you try to make it one (not many of us could do what Richard Proenneke did). A simple step toward partial self-sufficiency, like setting up a small emergency backup power supply, is enough to make a lot of families feel much better about their overall preparedness when the unexpected strikes.
Self-sufficiency can (and absolutely should) be researched before being attempted. Our own Solar Living Sourcebook is a truly excellent primer on the considerations and basics of off-grid living.
Out of crisis can come opportunity. Think back a few months…Did you catch yourself saying “I’m so busy! If only there were more hours in the day!” a month ago, and then “I’m so bored! How long am I going to be stuck in my house?” a week ago? There may be no time like the present to learn a new skill, catch up on reading, call some long-lost friends or relatives, or deep clean the house.
We are in this together and it’s not going away soon. The spring of 2020 – and likely the summer too – is going to be different from any we’ve lived through before. We are going to need to be patient, get by with less shopping and fewer luxuries, and be helpful to others while respecting their boundaries with social distancing.
We are not attempting to stoke fear, to say “I told you so”, or to leverage this global pandemic for financial gain. We are simply trying to make people aware that if self-sufficiency is a new, enticing, and/or daunting proposition that you’ve recently been forced to confront, there are professionals out there like us and others who specialize in building systems to deliver power and water to people who either need or want to be self-reliant in attaining these essentials.

We’re all in this together, and we here at Real Goods have been helping people secure their own power and water supplies for 41 years now. Give us a call at 800-919-2400 or check out these resources and products if you want to explore your self-sufficiency options.

Self-Sufficiency Resources

The Solar Living Sourcebook
“Solar Power for Beginners” video series with Solar Queen Amy Beaudet
Get a free quote for a battery backup system
Get a free quote for an off-grid solar power system
Get a free quote for a solar water pumping system
Self-Sufficiency Equipment
The Solar Living Sourcebook
Portable emergency backup power sources
Medium (7.5 kWh) integrated backup power supply
Large (over 10 kWh) integrated backup power supplies

Himax - Lifeppo4-Battery-In-The-Industrial-Field

Lithium iron phosphate battery is a lithium-ion battery that uses lithium iron phosphate (LiFePO4) as the positive electrode material and carbon as the negative electrode material. The rated voltage of the monomer is 3.2V, and the charge cut-off voltage is 3.6V~3.65V.

Application of the new energy automobile industry

Lithium iron phosphate batteries are widely used in passenger cars, buses, logistics vehicles, low-speed electric vehicles, etc. due to their safety and low-cost advantages. Although, in the current new energy passenger vehicle field, it is subject to the state’s subsidy policy for new energy vehicles. Influence, relying on the advantages of energy density, ternary batteries occupy a dominant position, but lithium iron phosphate batteries still occupy an irreplaceable advantage in fields such as passenger cars and logistics vehicles. In the field of passenger cars, lithium iron phosphate batteries remain mainstream. In the field of special-purpose vehicles, the proportion of lithium iron phosphate batteries is gradually increasing. The use of lithium iron phosphate batteries in the extended-range electric vehicle market can not only improve the safety of vehicles, but also support the marketization of extended-range electric vehicles, eliminating the anxiety of pure electric vehicles such as mileage, safety, price, charging, and subsequent battery issues.

Start the application on the power supply

In addition to the power lithium battery characteristics, the starter lithium iron phosphate battery also has the ability of instantaneous high-power output. The traditional lead-acid battery is replaced by a powerful lithium battery with an energy of less than one kilowatt-hour, and the traditional starter motor and generator are replaced by a BSG motor. , It not only has the function of start and stop at idle speed, but also has the functions of engine stop coasting, coasting and braking energy recovery, acceleration assist, and electric cruise.Application of energy storage market

Lithium iron phosphate battery has a series of unique advantages such as high working voltage, high energy density, long cycle life, low self-discharge rate, no memory effect, and green environmental protection. It also supports stepless expansion and is suitable for large-scale electric energy storage. Energy power stations have good application prospects in such fields as safe grid connection, grid peak shaving, distributed power stations, UPS power supplies, and emergency power systems.

With the rise of the energy storage market, in recent years, some power battery companies have deployed energy storage business to open up new application markets for lithium iron phosphate batteries. On the one hand, due to the characteristics of ultra-long life, safe use, large capacity, and environmental protection, lithium iron phosphate can be transferred to the energy storage field, which will extend the value chain and promote the establishment of new business models. On the other hand, energy storage systems supporting lithium iron phosphate batteries have become a mainstream choice in the market. According to reports, lithium iron phosphate batteries have tried to be used in electric buses, electric trucks, user-side, and grid-side frequency modulation.

Safe grid connection of renewable energy power generation

The inherent randomness, intermittent news, and volatility of wind power generation determine that its large-scale development will inevitably have a significant impact on the safe operation of the power system. With the rapid development of the wind power industry, especially most wind farms in my country are “large-scale centralized development and long-distance transmission”, the grid-connected power generation of large-scale wind farms pose severe challenges to the operation and control of large-scale power grids.

Photovoltaic power generation is affected by ambient temperature, sunlight intensity, and weather conditions, and photovoltaic power generation has the characteristics of random fluctuations. my country presents a development trend of “decentralized development, low-voltage on-site access” and “large-scale development, medium, and high voltage access” simultaneously, which puts forward higher requirements for power grid peak shaving and safe operation of the power system.

Himax - 200ah-12v-Battery-Pack

Therefore, large-capacity energy storage products have become a key factor in solving the contradiction between the power grid and renewable energy power generation. The lithium iron phosphate battery energy storage system has the characteristics of fast working condition conversion, flexible operation mode, high efficiency, safety, and environmental protection, and strong scalability. Engineering applications have been carried out in the national wind and solar storage and transmission demonstration project, which will effectively improve equipment efficiency and solve Local voltage control problems, improve the reliability of renewable energy power generation and improve power quality so that renewable energy can become a continuous and stable power supply.

With the continuous expansion of capacity and scale and the continuous maturity of integrated technology, the cost of energy storage systems will be further reduced. After long-term safety and reliability tests, lithium iron phosphate battery energy storage systems are expected to be used in wind power, photovoltaic power generation, etc. Safe grid connection of energy power generation and improvement of power quality are widely used.

Lithium iron phosphate battery for grid peak shaving

The main method of power grid peak shaving has always been pumped storage power stations. As the pumped storage power station needs to build two reservoirs, the upper and lower reservoirs are restricted by geographical conditions, it is not easy to construct in plain areas, and it covers a large area and high maintenance cost. Use lithium iron phosphate battery energy storage system to replace pumped storage power station, cope with grid peak load, free of geographical conditions, freedom of location, less investment, less land occupation, low maintenance cost, and will play an important role in the process of power grid peak regulation.

Lithium iron phosphate battery for distributed power station

The shortcomings of large-scale power grids make it difficult to guarantee the quality, efficiency, safety, and reliability requirements of the power supply. For important units and enterprises, dual power supplies or even multiple power supplies are often required as backup and protection. Lithium iron phosphate battery energy storage system can reduce or avoid power outages caused by grid failures and various accidents, and ensure a safe and reliable power supply for hospitals, banks, command and control centers, data processing centers, chemical materials industries, and precision manufacturing industries. Play an important role.

Lithium iron phosphate battery for UPS power supply

The sustained and rapid development of China’s economy has brought about the decentralization of UPS power users’ demand, which has caused more industries and more enterprises to have a continuous demand for UPS power.

Compared with lead-acid batteries, lithium iron phosphate batteries have the advantages of long cycle life, safety and stability, environmental protection, and low self-discharge rate. With the continuous maturity of integration technology, the cost continues to decrease. Lithium iron phosphate batteries are used in UPS power batteries. Will be widely used.

 

Applications in other fields

Lithium iron phosphate battery is also widely used in the military field because of its good cycle life, safety, low-temperature performance, and other advantages.

Himax - Lithium Ion Battery For Boat Or RV
Lithium Ion Battery For Boat Or RV

An example of modern technology implemented in the nautical vessel. Darling Harbor marina, Sydney, Australia.

It’s time. Your RV or boat’s lead-acid battery bank had a good run, but just isn’t able to hold a charge anymore – so what should you do? Using desulphators could help squeeze some more life out of it, but instead of asking how to restore lead-acid batteries that are clearly past their prime, the question you should be asking is: Can I replace lead-acid batteries with lithium batteries in my boat or RV? After all, lithium batteries are becoming the standard for renewable energy storage.

The answer is YES, you can absolutely replace lead-acid batteries with lithium in marine and RV applications – but here are a few considerations to help you decide if upgrading to lithium batteries is the right lead acid battery alternative for your boat, camper, or RV.

 

WHY REPLACE LEAD ACID BATTERIES WITH LITHIUM IN A BOAT OR RV?

Lead Acid vs. Lithium: Depth of Discharge

Depth of Discharge, or DoD, is how much of your battery bank’s stored energy can actually be used without dramatically reducing its life. For example, a 100Ah (amp hour) lead-acid battery rated for 25% DoD means you need to plan to use only ¼ of its rated capacity (so 25Ah), leaving the other ¾ in the battery, unused.

  • DoD for lead-acid batteries – both flooded (which you have to add water to periodically) and sealed (“maintenance-free”) – is typically in the 25% – 50% range. Your battery will last at least twice as long if you regularly discharge it 25% than if you regularly discharge it 50%. Keep in mind that if you don’t have a sunny day to recharge your batteries after a day of use, the DoD will go down again the next day – so planning to use 25% per day will allow you to use less than the 50% maximum after two days of use.
  • On the other hand, DoD for lithium ion batteries is 80% or more, allowing you to use most or even all of the battery’s stored energy. That means a 100Ah lithium battery rated for 80% DoD can safely provide you with 80Ah without being harmed.

As a result, a lithium battery bank can be much smaller than a lead-acid battery bank to provide the same amount of usable energy. For example, if you need 100Ah of energy a day, you would need a 400Ah lead-acid battery bank to stay at 25% DoD, but would only need 125Ah of lithium at 80% DoD. That is a significantly smaller battery bank with lithium batteries.

Lead Acid vs. Lithium: Cycle Count

Cycling a battery means discharging it to any amount and recharging it to a fully charged state. If you cycle your battery bank every day for a year, that’s 365 cycles. If you only use it on the weekends, and keep the bank topped off the rest of the time, that’s 104 cycles a year.

A cycle is a cycle regardless of how deep the discharge is, but the depth of discharge directly affects how many cycles you can expect your battery to last. A battery’s specs will tell you how many cycles to expect from it when discharging to its rated DoD.

  • A standard flooded lead-acid battery can have about 2500 cycles at 25% DoD
  • A standard sealed lead acid battery can have about 1200 cycles at 25% DoD
  • Unlike lead-acid, lithium batteries don’t have a cycle curve under 80% DoD. Beyond 80%, the cycle count can drop dramatically. A typical lithium battery can have 5000+ cycles at up to 80% DoD. That’s 4x the cycles at over 3x the DoD. That’s a much longer lived battery bank with lithium batteries.

Lead Acid vs. Lithium: Charge/Discharge Rate

In addition to how much of a battery’s capacity you use, it also matters how fast you use it. Again using the 100Ah battery example, if you have a 10 amp (A) load, that can drain the battery completely in 10 hours  (100Ah ÷ 10A = 10 hours). That is considered a C/10 rate. Likewise, if you have a 50A load on the same battery, that would drain it in 2 hours  (100Ah ÷ 50A = 2 hours). That is a C/2 rate. Most batteries are rated at their C/20 rate, emptying the battery in 20 hours.

If you have a high-current load in your system, or are charging it very quickly with a high current, such as your alternator or shore power, you need to consider the charge/discharge rate of the battery bank. If you need a higher rate than the batteries can handle, you would need to increase the battery bank by adding more batteries in parallel so that the batteries can share the current between themselves. This may result in needing a battery bank that has a higher Ah capacity than you need to power your loads, just to handle the high current.

Likewise, too slow of a charge of lead-acid batteries can cause premature sulphation, shortening their life. This is not a problem with lithium.

  • Lead-acid batteries tend to perform best between C/8 and C/12 rates. So our 100Ah battery would want to be charged or discharged at between 8A and 12A. Wiring three batteries in parallel would permit three times the rate, as it shares the current between the three, so 24A to 36A.
  • Some lithium batteries can generally handle a C/1 rate, or even higher for short periods depending on the battery. This means a 100Ah lithium battery can handle 100A (or more) of charge/discharge current. Most manufacturers recommend no more than a C/2 rate on a regular basis for best battery life, but it is good to know the extra power is there with lithium batteries if you need it. Be sure to check the manufacturer’s specs when selecting a lithium battery, as some do not support as high of a current as others.

Lead Acid vs. Lithium: Voltage Sag

You may be familiar with the voltage of your boat or RV’s battery bank sagging, or dropping to 11V or lower when trying to run a high-power load such as your winch, windlass, or air conditioner. When running a heavy AC load off the inverter, the voltage could drop below the low voltage cutoff, causing the inverter to turn off when you need it most. Likewise, if you are running a DC load like your bow thruster directly off the battery bank, you need it to maintain a high enough voltage for it to work when you really need it to work. Due to lithium batteries’ voltage curve and ability to handle high current, loads like these will not cause the voltage to drop dramatically, eliminating the problem of voltage sag.

Lead Acid vs. Lithium: Size and Weight

With a higher DoD, higher cycle count, and higher charge/discharge rate, it’s easy to see how using lithium batteries in your RV or boat saves space by requiring a physically smaller battery bank…and I don’t need to explain the advantages of saving space in an already tight spot. But there’s yet another physical benefit of replacing lead-acid batteries with lithium for RV and marine applications: Lithium batteries also don’t have the crazy weight from being made with lead! Lighter weight means higher fuel efficiency, saving you additional money in gas or diesel costs.

Lead Acid vs. Lithium: Safety

Safety is always a primary consideration when designing a solar system, but it becomes even more important when your system is on a boat far from shore, or an RV on a remote road. Different battery chemistries have different risk factors. Obviously, abusing any type of battery can create a dangerous situation. But with normal, and perhaps even a bit of rough treatment, the different batteries have different safety concerns that need to be addressed.

  • Flooded lead-acid batteries have an acid and water electrolyte in the battery that has to be checked on a regular basis. During normal charging cycles, this mixture turns into a gas that needs to be vented outside. A buildup of the gas inside a vehicle or vessel can be explosive. Proper ventilation mitigates this concern. The outgassing of the battery is normal, but requires owners to regularly check to see when the electrolyte level gets low from the outgassing. If low, it needs to have more distilled water added. This runs the risk of acid spills if overfilled or overcharged. This requires you to be prepared with proper safety equipment including gloves, safety glasses, and baking soda to neutralize the acid if needed.
  • Sealed lead-acid batteries do not have outgassing or electrolyte levels to check, as they do not outgas. Normal battery safety measures should be followed, like checking for tight cable connections, corrosion, and preventing physical damage to the battery itself.
  • Lithium batteries also do not outgas, but certain types (the ones with cobalt, known as lithium cobalt oxide or LCO) can experience thermal runaway – a condition where the battery starts to get hot, which causes it to react to the heat and get hotter and hotter until it catches on fire. LCO batteries are most commonly used in cell phones, hoverboards, and electric cars, and are generally not recommended for mobile applications.

So are lithium batteries any safer than other batteries? Yes – when they don’t contain cobalt. Lithium ferrous phosphate (LFP or LiFePO4) chemistry has become the standard lithium battery for marine, RV, and general solar PV use because they have no thermal runaway issues. They are very safe, can be installed indoors, and are a perfect solution for mobile living and recreation. Just as with sealed lead-acid batteries, making sure the cables haven’t shaken loose with vibration from travel, and a visual inspection to ensure all is well is all that is needed.

Lead Acid vs. Lithium: Temperature

Lead acid battery temperature de-ration table

Lead Acid Temperature Deration

Temperature has different impacts on different types of batteries. A lead-acid battery’s capacity is rated at 80°F (26°C), but the colder it gets, the more capacity falls. So our 100Ah lead-acid battery at 80°F holds only 76Ah at 40°F (4°C). As a result, if you know you are going to be using your battery bank in the winter, and they will be in an unconditioned location (not heated or cooled), you need to oversize your battery bank to make up for the smaller capacity when cold.

Lead-acid batteries also perform best when charged at different rates based on temperature. As a result, most quality solar charge controllers have a battery temperature sensor to report back to the charge controller.

Lithium batteries maintain the same capacity regardless of the temperature, and do not need their charging rate adjusted to account for temperature.

However, while you can run your loads in freezing temperatures, you cannot charge a lithium battery in sub-freezing temperatures (below 32°F or 0°C). A Battery Monitoring System (BMS) will often have cold temperature cut-off, preventing the battery from being charged when it is too cold.

12v 300Ah Lithium Battery

If your lithium battery bank is in a cold environment, you need to either get a battery that has a built-in heater like the Himax battery, and/or build an insulated battery box to hold in the heat generated while charging.

Lead Acid vs. Lithium: Lifetime Cost

If you compare lithium batteries to lead-acid batteries Ah to Ah, lithium batteries are more expensive. But step back and look at the bigger picture – taking into account everything we’ve covered so far – and you can see how lithium batteries can actually save you money, time, and hassle in the long run.

Let’s look at some cost examples when designing a battery bank for a 12V system that uses 1400Wh a day.

Sealed AGM vs. Lithium

For a lithium bank: 1400Wh x 2 days of autonomy ÷ 80% DoD (after 2 days without sun, daily is 40%) ÷ 12V battery bank = 290Ah battery. I’ll round up to 300Ah and use two  1800 at $1300 each for a total of $2600.For a sealed AGM battery bank: 1400Wh x 2 days of autonomy (days without sun) x 1.11 temperature derate (60F) ÷ 50% DoD (25% x 2 days without sun) ÷ 12V battery bank = 518Ah bank. I’ll round up to 600Ah and use 200Ah 12V batteries at $600 each for a total of $1800.

At first

12v 250Ah LiFePO4 Battery

Flooded Lead Acid vs. Lithium

 

glance, the lithium bank costs more than the AGM bank. But when you consider cycle counts (1200 for the AGM and 5000 for the lithium), the lithium battery bank will last 4x longer than the AGM bank. You would need to buy four AGM battery banks for $7200 – and spend the time shopping for and installing them – to match the lifetime of one lithium bank for $2600. Plus you’d miss out on all the previously mentioned benefits of lithium batteries for a boat or RV.

 

 

The math is the same for a flooded lead-acid battery bank as for a sealed one. So let’s again compare a 518Ah 12V lead-acid battery bank with the 300Ah 12V lithium bank. I’ll round up to 675Ah to use the popular Trojan T-105 225Ah 6V batteries at $175 each. Using 6V batteries will require 2 in series to get 12V, so I’ll need 6 for a total of $1050. We are still going to use two of the KiloVault HLX1800 for $2600, or I could use a single 300Ah 12V battery for the $2500. Some people prefer installing two batteries in parallel for redundancy and find that the size and weight of two batteries may be easier to manage than one.

The price gap between flooded lead-acid and lithium is greater than with AGM. With flooded’s 2500 cycles versus lithium’s 5000 cycles, a well maintained flooded battery bank can last half as long as lithium. But a poorly maintained flooded battery bank can quickly become a boat anchor in a year or two. So the flooded is a slightly less expensive solution than sealed lead-acid at $2100 for two banks vs. $2600 for one lithium. But again, you have the advantages of the smaller, lighter, safer battery bank, the higher current capability, and minimal maintenance needed on the lithium. It may be worth the extra $500 to you to go lithium.

Lead Acid vs. Lithium for Marine and RVs: The Verdict

By choosing lithium batteries as a lead-acid battery alternative for marine/RV applications, you will need fewer batteries, and those batteries will last longer, cycle  deeper, deliver more power, and weigh less.

CONSIDERATIONS WHEN REPLACING LEAD ACID BATTERIES WITH LITHIUM IN A BOAT OR RV

Now that you’re convinced lithium is the best way to go, you need to be aware of a few things when replacing a lead-acid battery with lithium. The term “drop-in replacement” has become popular, but the reality is there are a few other things you’ll need to do to safely upgrade from lead-acid to lithium batteries in your boat or RV.

Charge Controller/Charging Profile

If you are currently charging your lead acid batteries with solar, your alternator, and/or shore power, you may be able to keep your existing charge controller or inverter/charger. The charging and low voltage cutoff profiles for lithium batteries are a little different from lead-acid, so you need chargers that have adjustable charge rates. Different batteries will have different preferences, so be sure to see the manufacturer’s recommendations when configuring your charger. They will often recommend a Bulk and Absorb rate of around 14V, with an Absorption time of as little as 2 minutes, significantly less than the standard for lead-acid. With a Float voltage of just below 14V, you can maintain the charge without overcharging it. Because lithium has a very narrow voltage window, 12V is generally the lowest voltage you want before you shut off your loads.

Note: Unlike lead-acid batteries, lithium batteries do not always need to be recharged to their full 100% capacity. They actually prefer being in a partial state of charge. If you are going to be leaving your boat or RV for a season of storage, it is recommended that you leave the battery bank at around 90% state of charge. This leaves plenty of energy for small loads like the bilge pump or CO2 alarm, but helps maintain a healthy battery bank until you can get back to normal use.

Cranking Amps / Starter Battery

With lead-acid batteries, we are used to seeing a rating of CCA (cold crank amps) to show how many amps can be used to start an engine in the cold weather. Lithium batteries do not have the CCA rating. If you intend to replace a lead-acid battery with lithium for your starting battery, make sure the new lithium battery is rated to handle enough current to do so. Not all of them are. We see a lot of people continue to use a lead-acid battery as the starter, with lithium used only for the house/service battery. This also gives you a bit of a backup, so that if everything goes wrong with your house/service battery, you still have the starter battery available.

Alternator

Unlike lead-acid batteries, lithium batteries have very little internal resistance and can take as much charging current from the alternator as needed. But since alternators are not designed to run at full speed for long periods, this can result in the alternator working too hard, overheating, and damaging itself. There are a few ways to prevent this from happening.

Use a DC/DC Converter

By installing a DC-to-DC converter between the alternator and the lithium battery bank, you can limit the amount of current the battery draws from the alternator. It is recommended that you only draw from the alternator at half its rating, so for a 60A alternator, a 30A DC/DC converter like the Bluetooth-enabled Victron Energy Orion-Tr Smart 12/12-30A charger is a good option. You can use multiple DC/DC converters in parallel to increase the rate for larger alternators.

Victron Orion-TR Smart DC/DC Converter system diagram

Victron Orion-TR Smart DC/DC Converter setup

Replace the Alternator

You can replace the alternator with one designed for higher amperage charging and temperature control. Balmar makes great alternators and external regulators for this. They monitor the temperature and will wind down to appropriate amperage if the alternator gets too hot. If you currently have a V-belt, you may need to modify the engine for a serpentine belt before you can use the larger Balmar alternator.

Low Voltage Disconnect

The ability to automatically disconnect your DC loads gives you control over how low you discharge your battery bank. An automatic switch such as the Victron Energy Smart BatteryProtect can be configured via Bluetooth for excellent control of your system. It can turn your non-critical loads on or off based on a configurable voltage setting.

Battery/Bank Monitoring

KiloVault CHLX Bluetooth App

Any good battery system should have the ability to monitor both the individual batteries, and the whole battery bank. Watching more than just the voltage, but also how many amps go in and out of the battery bank and the temperature gives you a complete view of the health and state of charge of the entire bank. Some lithium battery Battery Monitoring Systems have Bluetooth or WiFi built in to allow you to monitor it from the phone. For example, the KiloVault HLX and CHLX batteries have Bluetooth to your Smartphone to see down to the cell level of each battery.

 

 

 

 

 

The Victron Energy Smart Shunt provides a low cost method to monitor your whole battery bank via Bluetooth from your smartphone. It does not include a display, so you can only view it via Bluetooth.

Victron SmartShunt system diagram

Victron SmartShunt – Monitors Batteries via Bluetooth

 

 

 

 

 

 

 

 

 

The Victron Energy Smart Battery Monitor BVM-712 gives you a local display for convenient viewing of battery voltage, current, power, amp-hours consumed, and state of charge (SoC). It can also be viewed via BlueTooth.

IT’S TIME TO MOBILIZE WITH LITHIUM BATTERIES FOR MARINE AND RV APPLICATIONS

Whether you are looking for a new battery bank for your RV or boat or considering replacing your aging lead-acid batteries, deep-cycle lithium-ion batteries – specifically LiFePO4 batteries – are an excellent solution. Compared to lead-acid batteries, LiFePO4 batteries offer more power, higher current, a longer life, smaller footprint, lower weight, and safe, maintenance-free operation. Are you ready to mobilize and go lithium?

See more options for lithium batteries at our website or contact us at (86)755-2562 9920 to help you select the right lithium batteries for your specific needs.

 

Himax - LiFePO4-Batteries

Safety is a full-fledged design feature with lithium batteries, and for good reason.

As we’ve all seen, the chemistry and energy density that allows lithium-ion batteries to work so well also makes them flammable, so when the batteries malfunction, they often make a spectacular and dangerous mess.

All lithium chemistries are not created equal. In fact, most American consumers – electronic enthusiasts aside – are only familiar with a limited range of lithium solutions. The most common versions are built from cobalt oxide, manganese oxide and nickel oxide formulations.

First, let’s take a step back in time. Lithium-ion batteries are a much newer innovation and have only been around for the last 25 years. Over this time, lithium technologies have increased in popularity as they have proven to be valuable in powering smaller electronics – like laptops and cell phones. But as you may recall from several news stories over recent years, lithium-ion batteries also gained a reputation for catching fire. Until recent years, this was one of the main reasons lithium wasn’t commonly used to create large battery banks.

LiFePO4-Batteries

But then came along lithium iron phosphate (LiFePO4). This newer type of lithium solution was inherently non-combustible while allowing for slightly lower energy density. LiFePO4 batteries were not only safer, they had many advantages over other lithium chemistries, particularly for high power applications, such as renewable energy.

Before we dive into the safety features of lithium iron phosphate, let’s refresh ourselves on how lithium battery malfunctions happen in the first place.

Lithium-ion batteries explode when battery’s full charge is released instantly, or when the liquid chemicals mix with foreign contaminants and ignite. This typically happens in three ways: physical damage, overcharging or electrolyte breakdown.

For example, if the internal separator or charging-circuitry is damaged or malfunctions, then there are no safety barriers to keep the electrolytes from merging and causing an explosive chemical reaction, which then ruptures the battery packaging, combines the chemical slurry with oxygen and instantly ignites all of the components.

There are a few other ways lithium batteries can explode or catch on fire, but thermal runaway scenarios like these are the most common. Common is a relative term though, because lithium-ion batteries power most rechargeable products on the market, and it’s pretty rare for large-scale recalls or safety scares to happen.

Although lithium iron phosphate (LiFePO4) batteries aren’t exactly new, they’re just now picking up traction in Global commercial markets. Here’s a quick breakdown on what makes LiFePO4 batteries safer than other lithium battery solutions.

LiFePO4 batteries are best known for their strong safety profile, the result of extremely stable chemistry. Phosphate-based batteries offer superior chemical and mechanical structure that does not overheat to unsafe levels. Thus, providing an increase in safety over lithium-ion batteries made with other cathode materials.

This is because the charged and uncharged states of LiFePO4 are physically similar and highly robust, which lets the ions remain stable during the oxygen flux that happens alongside charge cycles or possible malfunctions. Overall, the iron phosphate-oxide bond is stronger than the cobalt-oxide bond, so when the battery is overcharged or subject to physical damage then the phosphate-oxide bond remains structurally stable; whereas in other lithium chemistries the bonds begin breaking down and releasing excessive heat, which eventually leads to thermal runaway.

Lithium phosphate cells are incombustible, which is an important feature in the event of mishandling during charging or discharging. They can also withstand harsh conditions, be it freezing cold, scorching heat or rough terrain.

When subjected to hazardous events, such as collision or short-circuiting, they won’t explode or catch fire, significantly reducing any chance of harm. If you’re selecting a lithium battery and anticipate use in hazardous or unstable environments, LiFePO4 is likely your best choice.

Most LiFePO4 batteries also come with a Battery Management System (BMS) that have many extra safety features including; over-current, over-voltage, under-voltage and over-temperature protection and the cells come in an explosion-proof stainless steel casing.

It’s also worth mentioning, LiFePO4 batteries are non-toxic, non-contaminating and contain no rare earth metals, making them an environmentally conscious choice. Lead-acid and nickel oxide lithium batteries carry significant environmental risk (especially lead acid, as internal chemicals degrade structure over team and eventually cause leakage). Compared to lead-acid and other lithium batteries, lithium iron phosphate batteries offer significant advantages, including improved discharge and charge efficiency, longer life span and the ability to deep cycle while maintaining performance. LiFePO4 batteries often come with a higher price tag, but a much better cost over life of the product, minimal maintenance and infrequent replacement makes them a worthwhile investment and a safer long-term solution.

Himax - Portable Power Supply

Portable Power Supply

What is a Portable Power Station?

As energy-dense lithium battery technology has advanced over the last 10 years, portable power stations have emerged as a useful solution for off-grid power. A portable power station is an easily transportable lithium battery that combines a built-in battery gauge, an inverter with AC outlet, and multiple DC outlets to provide power for common devices while you’re off the grid.

All electronic devices use either AC or DC electricity. An alternating current (AC) is the more commonly recognized type of electricity. Most household appliances, including air conditioning, microwaves, refrigerators, and hair dryers, run off AC. Less commonly recognized than AC, direct current (DC) is used in devices that have a battery as their power source. These include cell phones, laptops, portable speakers, and cameras.

If you were to purchase a battery by itself it would not be useful to power all your devices. Power stations are useful because they merge an inverter to power AC devices (standard two or three-prong US wall socket type) with different connectors to power DC devices all in one unit. Some familiar DC outlet types include USB-A, USB-C, barrel jacks, and 12V car power sockets (also known as cigarette lighter sockets). Good portable power stations include not only a standard charger that plugs into the wall at home, but also allow for charging from a solar panel.

Portable Power Station

Advantages of a Portable Power Station

Whether you need power when camping, fishing, tailgating, on the job site, or in an emergency, a portable power station can provide electricity when and where you need it. When looking at the advantages of a portable power station, a comparison must be made to their alternative, which is a fossil fuel generator. Although generators provide an endless amount of power as long as you have the fuel, they are noisy, emit dangerous greenhouse gases (carbon monoxide and carbon dioxide), and require regular running and maintenance, including oil changes, cleaning air filters and spark arrestors, and potentially cleaning out the carburetor when it gets clogged by dirty fuel.

Conversely, portable power stations do not require any maintenance besides discharging and recharging at least once every six months. They are silent and can be used indoors without fear of asphyxia. Despite their finite capacity, their capacity limitations can be overcome by planning for and purchasing a power station with enough watt-hours in reserve to get you through your intended adventure and/or supplementing capacity with a solar panel.

Depending on the continuous watt rating and capacity, a portable power station can be used to power almost any device for as long as you want. You can calculate your power needs, size your battery bank and determine your solar requirements here.

Himax’s Portable Power Station

RELiON Outlaw 1072S运行时

We currently offer the H-1000w, which is a 1000-watt continuous 2000-watt peak, 921-watt hour portable power supply, which is capable of charging through a solar panel (150-watt max). The Outlaw is powered by LiFePO4 cells capable of 2,000-lifetime cycles at 80% depth of discharge with proper care. The H-1000w can power most creature comforts you would want while camping or tailgating, or if your power went out at home for an extended period.

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