RV House Batteries

Part of RV ownership is maintenance. In this video, we replace our motorhome’s 4 house batteries and talk about some things we’ve learned about battery maintenance. We hope that you can learn from our mistakes to get the most out of your RV’s battery life. We replaced 4 6-volt golf cart batteries with 4 new 6-volt golf cart batteries. We did a lot of research to decide what batteries to buy and we learned a few things along the way.

Tips for Replacing Your RV’s House Batteries

Study Your Battery Bank Before You Start! Before you begin removing your old house batteries, be sure that you take pictures of the compartment so that you can see how everything is connected. Some RV battery bays are pretty tight and it can be difficult to see everything in the back, so be sure to snap some photos in the back of the bay as well. We’d also suggest drawing a simple diagram to remind you of how the batteries are positioned, where the positive and negative terminals are located and which cables connect to what so that you can be sure all of your cables will reach what they need to.

Decide What Type of Battery is Right For You There are three main types of batteries used for RV house batteries: traditional lead acid (also called flooded cell batteries), AGM (which stands for Absorbed Glass Mat or sometimes Absorbent Glass Mat depending on where you look), and Lithium. The type of batteries you choose can be based on price, space, power needs and how you use your RV. Whichever you decide to go with, all of your batteries should be the same type, size and age. Be consistent.

Save Money By Recycling Retailers today will charge a “core” fee when you are buying batteries. This is a recycling fee that is placed on every battery. We avoided this fee by giving them our old batteries when we bought the new ones.

Not All Batteries Are Created Equal Do your research ahead of time to determine what will be right for your needs. RV House Batteries are available in 6-volt and 12-volt and in a wide variety of amperages. Know what you currently have and how that works out for you. And spend some time doing some research online to narrow down what you are looking for so you aren’t wasting gas running all over town. And remember, 6-volt batteries will be connected differently than 12-volt batteries. So, again, pay close attention to how your batteries are connected.

RV Battery Quick Fill System

Using Our Battery Quick Fill System to Top Off Our House Batteries

If You Choose Lead Acid Batteries You will need to maintain the level of distilled water in your batteries. This can be a pain in the butt if some of your batteries are difficult to access. Since 2014, we have used a battery quick fill system to easily and quickly add distilled water to our house batteries. The filling tubes stay connected at all times. When it’s time to check the water level, we connect the end of that tube to our hand pump which has another tube that we put down into the bottle of distilled water. All we have to do is squeeze the pump a a few times. It tops off all of our house batteries simultaneously and will not allow them to overfill. It is really super simple and we highly recommend it. As long as we have lead acid batteries in our RV, we will use a battery quick fill system! Here’s one like ours if you’d like to get one for yourself: Flow-Rite RV2000 RV Edition 2 Battery Kit. (We have 2 of these since we have 4 6-volt house batteries.)

Types of RV House Batteries

Lead Acid Batteries Also called “flooded cell” batteries, lead acid batteries are the least expensive option for replacing the house battery bank in most RVs. They are also the most common type of battery you’ll probably find in most campers. The price is nice (especially when you are replacing multiple batteries), but there are a few downsides to lead acid batteries. They require more maintenance than the other types of batteries. As we mentioned above, you have to keep a close eye on the fluid levels of these batteries. Low fluid levels can affect performance and may significantly shorten your battery’s life. With the quick fill system we suggest above this is super easy to do, but you have to remember to perform this maintenance regularly.

You also want to keep an eye on the charge level of your lead acid batteries. We’ve read that allowing the battery charge level to drop below 50% will potentially damage the battery and shorten its life. This isn’t a problem when you are plugged into shore power, but be very mindful of your charge levels if you are boondocking and be sure to check on your batteries regularly when your RV is in storage! Lead acid batteries will lose their charge in storage even if you have disconnected them.

AGM Batteries Absorbed Glass Mat batteries are sealed and do not require you to add distilled water. So they require a little less maintenance than lead acid batteries, but they are also more expensive. You still need to monitor your charge levels just like you would with lead acid batteries. Just like their lead acid cousins, AGM batteries will lose their charge in storage even when disconnected.

We’ve read reports that say that AGM batteries may recharge more quickly than lead acid, but they may also be more sensitive to overcharging. Some articles we read also said that AGMs might be more sensitive to temperature changes than their lead acid counterparts.

Lithium Batteries The newest option (and the technology that seems to be quickly changing at the moment) is lithium. Lithium batteries are a lot more expensive than the other options. Traditionally, they are sized completely differently than most RV house batteries and have been known to be very sensitive to temperature. However, they are lighter in weight (which is always a good thing in RVs!), more powerful, and can use up more of their charge without risking damage to the life of the battery.

We’ve read that the latest chemistries in lithium batteries for RVs are less sensitive to temperature changes and allow the batteries to maintain their charge in storage for up to a year! When we were doing our research, we came across some new lithium batteries that were sized just like the 6-volt golf cart batteries (GC2) we currently have, so they would have worked easily with our existing battery location and brackets.

Tips for Maintaining Your RV’s Batteries

Keep An Eye On the Water Levels We can’t stress this one enough! If you have lead acid batteries, like us, then you have to maintain the distilled water levels of your batteries. Start checking those water levels as soon as you buy your RV. Even brand new RVs can have batteries without sufficient water. (Maybe that particular RV has been on the lot for a little while?) Never assume what your RV has been through before you found it. Be consistent about checking the fluid levels and maintain them easily with a Flow-Rite battery quick fill system. (Have we told you how much we love ours? It has saved us a ton of head bumping and unmentionable language over the years!) 🙂

Use a Trickle Charge If you have access to a standard 110 power plug, you can use a Camco 30amp to 15amp Adapter or a Camco 50amp to 15amp Dogbone Adapter to trickle charge your RV’s house batteries while it is in storage. However, do not assume that it is charging just because you have it plugged in. If the power to your storage area fails for any reason, your RV batteries may end up discharging instead of charging. This happened to us twice. So always go back within 24 hours after you plug in to trickle charge to check on your batteries. We’ve read that your batteries should be fully charged within that 24 hours, so you’ll want to unplug them and disconnect them at that point anyway. (especially if you do not have a good energy management system to keep your batteries from overcharging)

Don’t Assume Anything We have learned this the hard way! The batteries are the heart of your RV. There is nothing worse than getting ready for a camping trip only to find that your batteries are low or dead. Be proactive in maintaining your batteries and you will never be surprised. This is especially true for part-time or seasonal RVers. Be sure you check on your batteries regularly. Don’t assume anything when it comes to them.

Disconnect the Batteries When Not Using or Charging If you are storing your RV, even for a few days, and you will not be trickle charging the batteries, be sure to disconnect them. For our travel trailer, this meant physically disconnecting the battery cable. In our motorhome, it means that we set the inside battery button to “Store” and the chassis battery switch inside our battery bay to “Off”. We’ve also learned to check to make sure the Inverter/Charge Controller is turned off before we set these battery switches. But remember, lead acid and AGM batteries will still lose some of their charge even when they are disconnected. So be sure to come back to check on them at least every couple of weeks.

Use Your RV As Often As Possible! RV batteries like to be used, so try to get out and go camping as often as possible (as if you need another excuse, right?). It’s also easier to remember to check and maintain your batteries when you are using it than when it is in storage away from you.


Battery capacity (how many amp-hours it can hold) is reduced as temperature goes down, and increased as temperature goes up. This is why your car battery dies on a cold winter morning, even though it worked fine the previous afternoon. If your batteries spend part of the year shivering in the cold, the reduced capacity has to be taken into account when sizing the system batteries. The standard rating for batteries is at room temperature 25 degrees C (about 77 F). At approximately -22 degrees F (-30 C), battery Ah capacity drops to 50%. At freezing, capacity is reduced by 20%. Capacity is increased at higher temperatures – at 122 degrees F, battery capacity would be about 12% higher.

Low Temperature Battery

Wide temperature variations

Battery charging voltage also changes with temperature. It will vary from about 2.74 volts per cell (16.4 volts) at -40 C to 2.3 volts per cell (13.8 volts) at 50 C. This is why you should have temperature compensation on your lead-acid battery charger or charge control if your batteries are outside and/or subject to wide temperature variations.

Internal temperature of a battery

Thermal mass means that because they have so much mass, they will change internal temperature much slower than the surrounding air temperature. A large insulated battery bank may vary as little as 10 degrees over 24 hours internally, even though the air temperature varies from 20 to 70 degrees. For this reason, external (add-on) temperature sensors should be attached to one of the POSITIVE plate terminals, and bundled up a little with some type of insulation on the terminal. The sensor will then read very close to the actual internal battery temperature.

Battery life reduces at higher temperatures

Even though battery capacity at high temperatures is higher, battery life is shortened. Battery capacity is reduced by 50% at -22 degrees F – but battery LIFE increases by about 60%. Battery life is reduced at higher temperatures – for every 15 degrees F over 77, battery life is cut in half. This holds true for ANY type of lead-acid battery, whether sealed, Gel, AGM, industrial or whatever. This is actually not as bad as it seems, as the battery will tend to average out the good and bad times.

One last note on temperatures – in some places that have extremely cold or hot conditions, batteries may be sold locally that are NOT standard electrolyte (acid) strengths. The electrolyte may be stronger (for cold) or weaker (for very hot) climates. In such cases, the specific gravity and the voltages may vary from what we show.

Now we have launched a low temperature battery, HiMASSi Smart & Temp battery, which supports charging at -31 ℉.

Welcome to consult! (sales6@himaxelectronics.com).


Low-temperature olymer lithium batteries

By now, the winter has been successful in many areas. Climate experts predict that the cold air may hit us frequently this winter, and we have ourselves prepared to prevent the cold. Will the batteries, the essential energy supply, and the energy storage device that we live in, also be prepared for the cold days?

For example, in terms of the necessary phone, a fully charged cell phone flies from a warm place to the cold north, when off the plane its power drops sharply or immediately shows “low power for low temperature, automatic shut”. Not only unpaid but also the temperature defeats it. when the phone battery encounters a low temperature beyond its acceptable range, it stops running (also phone freezing phenomenon) so that the mobile phone powers down or automatically off. Knowing the temperature accepted by our batteries is necessary.

batteries power our life
Picture 1: Batteries power our life.

Battery classification on the temperature

Normal temperature battery

This kind of battery is just like humans who enjoy the temperature indoor. Its operating temperature range is generally 0℃~60℃. Under normal circumstances, the temperature is about 45℃, if it exceeds 50 degrees, it will be very hot, and the battery will be easy to age and scrap, such as our commonly used mobile phone battery, mobile power supply, etc. If below minus 20℃, the device with it can’t work normally and it easily ages too.

High-temperature battery

The High-temperature battery uses a solid and inactive electrolyte at a normal ambient temperature. It can only become active at high temperatures by heating from the outside, which is used almost exclusively for military applications.

Low-temperature battery

A low-temperature battery is a battery with strong freezing capacity by adding resistance to the conventional ones and production research and development of technology. Because of the performance advantages of lithium-ion itself, it has become the protagonist in both the institute and the market.

Wide temperature battery

Wide temperature battery with a larger operating temperature range always over 100℃ (like -40℃-80℃ Ni-MH battery)can be applied to other harsh environmental fields such as petroleum drilling and aerospace.

Treat the effect of temperature on the battery

How to maintain the mobile phone in winter?

We have no idea to replace the battery of our mobile phones. But we have some tips to protect it from cold damage:

Before being out
  • Equip the phone with a thicker and warmer phone case (Picture 2 ).
  • Stick the mobile phone membrane for anti-static electricity.
  • Prepare a charging bank and the line.
equip our electronic against this winter
Picture 2: Equip our electronics against this winter.
When staying outdoor
  • Put it into a pocket (inside the clothes) or bag to keep warm.
  • Use the headphones instead of releasing the sound out and shorten the outdoor-use time.
  • No mobile phone for a large temperature difference.
  • Do not start it up immediately after an automatic shut down until the temperature of the phone becomes normal.

Choose the correct battery to avoid unnecessary trouble

The battery activity is reduced for the low temperature, which affects charging and limits the use of electricity.  If we are going to have a new product. the battery choosing must be taken seriously. When we have to get outdoor to a temperature under 40℃, low-temperature polymer lithium batteries can be your best choice. Maybe you need a battery for your device to climb a mountain or other unique demand. Specializes in battery solutions against different temperatures. There are more suggestions for you, just click here to know more or contact us.

Definition of Series and Parallel Connection of Lithium Batteries

Due to the limited voltage and capacity of the single battery cell, the series and parallel connection is needed in the actual use to obtain higher voltage and capacity, so as to meet the actual power demand of the equipment.

  • Lithium batteries connected in series
    Add the voltage of batteries, capacity remains the same, and internal resistance increases.
  • Lithium batteries connected in paralle
    Constant voltage, added capacity, reduced internal resistance, and extended power supply time.
  • Lithium batteries connected in series and parallel
    3.7V single battery can be assembled into battery pack with a voltage of 3.7*(N)V as required (N: number of single batteries)
    For example, 7.4V, 12V, 24V, 36V, 48V, 60V, 72V, etc.
  • Capacity of Parallel Connection
    2000mAh single battery can be assembled into a battery pack with capacity of 2*(N)Ah as required (N: number of single batteries)
    For example, 4000mAh, 6000mAh, 8000mAh,5Ah10Ah20Ah, 30Ah, 50Ah100Ah, etc.

Lithium Battery Pack

Lithium battery pack technique refers to the processing, assembly and packaging of lithium battery pack. The process of assembling lithium cells together is called PACK, which can be a single battery or a lithium battery pack connected in series or parallel. The lithium battery pack usually consists of a plastic case, PCM, cell, output electrode, bonding sheet, and other insulating tape, double-coating tape, etc.

  • Lithium cell: The core of a finished battery
  • PCM: Protection functions of over charge, over discharge, over current, short circuit, NTC intelligent temperature control.
  • Plastic case: the supporting skeleton of the entire battery; Position and fix the PCM; Carry all other non-case parts and limit.
  • Terminal lead: It can provide a variety of terminal wire charging and discharging interface for a variety of electronic products, energy storage products and backup power.
  • Nickel sheet/bracket: Connection and fixing component of the cell


Lithium Battery Pack Structure

Lithium Battery Series and Parallel Connection

Due to security reasons, lithium ion batteries need an external PCM used for battery monitoring for each battery. It is not recommended to use batteries in parallel. If connect in parallel, make sure the consistency of the battery parameters (capacity, internal resistance, etc.), the other batteries in series need to have consistent parameters, otherwise, the performance of the battery pack can be much worse than the performance of a single cell.

Lithium Battery Series and Parallel Connection

Lithium battery matching criteria
voltage difference ≤ 10 mv, impedance difference ≤ 5 mΩ, capacity difference ≤20mA

The purpose of lithium battery matching is to ensure that every cell in the battery has consistent capacity, voltage and internal impedance, because inconsistent performances will make lithium battery have various parameters during using. Voltage imbalance will happen. After a long run, the battery will overcharge, over discharge, capacity lost, or even fire to explode.

Two Lithium Batteries Connected in Series (7.4V Lithium Battery)

Two Lithium Batteries Connected in Series
model 18650-2S1P 18650-2S1P 18650-2S2P 18650-2S3P
Voltage 7.4V 7.4V 7.4V 7.4V
Capacity 2200/2500/3000mAh 2200/2500/3000mAh 6000mAh 9000mAh
Dimension 18*105mm 18*36*65mm 37*37*66mm 37*55*66mm
Weight 90g 90g 180g 270g

Three Lithium Batteries Connected in Series (11.1V Lithium Battery)

Three Lithium Batteries Connected in Series
Series and Parallel Connection Mode 18650-3S1 P triangle 18650-3S1P in-line 18650-3S2P 18650-3S3P
Voltage 11.1V 11.1V 11.1V 11.1V
Capacity 2200/2500/3000mAh 2200/2500/3000mAh 6000mAh 9000mAh
Dimension 66.5*36.6*36.6mm 69.8*55.7*18.8mm 66.8*55.0*40.8mm 60.6*68.0*56.1mm
Weight 155g 158g 285g 425g

Four Lithium Batteries Connected in Series (14.8V Lithium Battery)

Four Lithium Batteries Connected in Series
Series and Parallel Connection Mode 18650-4S1P square 18650-4S1P In-line 18650-4S2P
Voltage 14.8V 14.8V 14.8V
Capacity 2200/2500/3000mAh 2200/2500/3000mAh 6000mAh
Dimension 69.6*37.7*37.7mm 69.3*73.4*17.6mm 70.6*74.2*37.1mm
Weight 181g 191g 371g

Six Lithium Batteries Connected in Series (22.2V Lithium Battery)

Six Lithium Batteries Connected in Series
Series and Parallel Connection Mode 18650-6S1P In-line 18650-6S2P 18650-6S3P
Voltage 25.2V 25.2V 25.2V
Capacity 2000/3000mAh 6000mAh 9000mAh
Dimension 114*72*22mm 114*72*41mm 114*72*60mm
Weight 303g 570g 835g

The length of the plug and lead of the lithium battery pack can be customized according to the customer’s electrical equipment.

Lithium Battery Wire/Terminal

We all know that lithium battery voltage increases after series connection, capacity increases after parallel connection, then how to calculate a lithium battery quantity of series or parallel connection, and how many cells?

Before the calculation, we need to know which cell specification of the battery pack is adopted for the assembly, because different cells have different voltage and capacity. The cell quantity of series and parallel connection required to assemble a specific lithium battery pack varies. The common lithium cell types on the market are:3.7V LiCoO2, 3.6V ternary, 3.2V LFePO4, 2.4V lithium titanate. The capacity is different because of the cell size, material and manufacturers.

Take 48V 20Ah Lithium Battery Pack for Example

  • Suppose the size of the single cell used is 18650 3.7V 2000mAh
  • Cell quantity of series connection: 48V/3.7V=12.97. That is 13 cells in series.
  • Cell quantity of parallel connection: 20Ah/2Ah=10. That is 10 cells in parallel.

Commonly Used Lithium Battery Connected in series

Nominal Voltage Battery Category Common Quantity of series connection Charging Voltage
12V 3.7V LiCoO2 3S 12.6V
3.2V LiFePO4 4S 14.6V
24V 3.7V LiCoO2 7S 29.4V
3.2V LiFePO4 8S 29.2V
36V 3.7V LiCoO2 10S 42.0V
3.7V LiCoO2 11S 46.2V
3.2V LiFePO4 11S 40.2V
3.2V LiFePO4 12S 43.8V
48V 3.7V LiCoO2 13S 54.6V
3.7V LiCoO2 14S 58.8V
3.2V LiFePO4 15S 58.8V
3.2V LiFePO4 16S 58.8V
60V 3.7V LiCoO2 17S 71.4V
3.2V LiFePO4 20S 73.0V
72V 3.7V LiCoO2 20S 84.0V
3.2V LiFePO4 24S 87.6V

Lithium Battery Assembly Process

18650-3S6P/11.1V/15600mAh Lithium Battery Assembly Process

  • Cell Capacity Grading

    Cell Capacity Grading
    Capacity Difference≤30mAh
    After capacity grading, stay still for 48-72h and then distribute.

  • Voltage Internal Impedance Sorting and Matching

    Voltage Internal Impedance Sorting and Matching
    Voltage Difference≤5mV
    Internal Impedance Difference≤5mΩ 8 cells with similar voltage internal impedance are distributed together.

  • Cell Spot Welding

    Cell Spot Welding
    The use of formed nickel strip eliminates the problems of spurious joint, short circuit, low efficiency and uneven current distribution

  • Welded PCM

    Welded PCM
    Make sure that the circuit board has no leakage components, and the components have no defective welding.

  • Battery Insulation

    Battery Insulation
    Paste the fibre, silicone polyester tape for insulation.

  • Battery Pack Aging

    Battery Pack Aging
    For the quality of the battery, improve the stability, safety and service life of the lithium battery.

  • PVC Shrink Film

    PVC Shrink Film
    Position the two ends after heat shrinking,
    then heat shrink the middle part.
    Put PVC film in the middle. No whiten after stretching. No hole.

  • Finished Product Performance Test

    Finished Product Performance Test
    Internal Impedance:≤150mΩ
    Charge-discharge and overcurrent performance test.

  • Battery Code-spurting

    Battery Code-spurting
    Code-spurting cannot be skewed, and it needs legible handwriting

Precautions for Lithium Batteries in Series and Parallel

  • Don’t use batteries with different brands together.
  • Do not use batteries with different voltages together.
  • Do not use different capacities or old and new lithium batteries together.
  • Batteries with different chemical materials cannot be used together, such as nickel metal hydride and lithium batteries.
  • Replace all batteries when electricity is scarce.
  • Use the lithium battery PCM with corresponding parameters.
  • Choose batteries with consistent performance. Generally, distributing of lithium battery cells is required for series and parallel connection. Matching standards: voltage difference≤10mV, impedance difference ≤5mΩ, capacity difference ≤20mA

Due to the consistency issue of lithium batteries, when the same system (such as ternary or lithium iron) is used for series or parallel connection, it is also necessary to select the batteries with the same voltage, internal impedance and capacity for matching. Batteries with different voltage platforms and different internal impedance used in series will cause a certain battery to be fully charged and discharged first in each cycle. If there is a PCM and no fault occurs, the capacity of the whole battery will be reduced. If there is no PCM, the battery will be overcharged or over discharged, which will damage the battery.

Full voltage not available

If different capacities or old and new lithium batteries are used together, there may be leakage, zero voltage and other issues, because during the charging process, capacity differences make some batteries overcharge, some batteries not, while during discharge process, high capacity batteries do not run out of power, but low capacity batteries over discharge. In such a vicious cycle, the batteries will be damaged by leakage or low (zero) voltage.

Full Capacity not available

To assemble lithium batteries, connect them in parallel or in series first?

  • Topological Structure of Lithium Battery Connected in Series and Parallel

The typical connection modes of a lithium battery pack are connecting first in parallel and then in series, first in series and then in parallel, and finally, mixing together.
Lithium battery pack for pure electric buses is usually connected first in parallel and then in series.
Lithium battery pack for power grid energy storage is tend to be connected first in series and then in parallel.

  • First Parallel and Then Series of Power Battery Module Topological Structure
    First Parallel and Then Series of Power Battery Module Topological Structure
  • First Series and Then Parallel of Power Battery Module Topological Structure
    First Series and Then Parallel of Power Battery Module Topological Structure
  • First Parallel, Then Series and Parallel Again of Power Battery Module Topological Structure
    First Parallel, Then Series and Parallel Again of Power Battery Module Topological Structure
  • Advantages of Lithium Batteries First Connected in Parallel and Then in Series
    If a lithium battery cell automatically exits, except the capacity reduction, it does not affect parallel connection;
    In parallel connection, a short circuit of a lithium battery cell may cause short circuit due to large current, which is usually avoided by using fuse protection technology.
  • Disadvantages of Lithium Batteries First Connected in Parallel and Then in Series
    If a lithium battery cell automatically exits, except the capacity reduction, it does not affect parallel connection;
    In parallel connection, a short circuit of a lithium battery cell may cause short circuit due to large current, which is usually avoided by using fuse protection technology.
  • Advantages of Lithium Batteries First Connected in Series and Then in Parallel
    First connecting the batteries in series according to the capacity, for example, 1/3 of the whole battery capacity are connected in series, and then connecting the rest in parallel, will reduce the failure probability of high-capacity lithium battery modules. First series and then parallel connection help the consistency of the lithium battery pack.
  • From the perspective of the reliability of the lithium battery connection, the development trend of voltage inconsistency and the influence of performance, the connection mode of first parallel and then series is better than that of first series and then parallel, and the topology structure of first series and then parallel lithium battery is conducive to the detection and management of each lithium battery cell in the system.

Lithium Batteries Charging in Series and Parallel

At present, lithium battery tends to be charged in series, which is mainly due to its simple structure, low cost and easy realization. But as a result of different capacity, internal impedance, aging characteristics and self-discharge performance, when charge lithium battery in series, battery cell with the smallest capacity will be fully charged first, and at this point, the other battery cell is not full of electricity. If continue to charge in series, the fully charged battery cell may be overcharge.

Lithium Battery overcharge will damage the battery performance, and even lead to explosion and injuries, therefore, to prevent battery cell overcharging, lithium battery has equipped with Battery Management System (BMS). The Battery Management System has overcharge protection for every single lithium battery cell, etc. When charging in series, if the voltage of a single lithium battery cell reaches the overcharge protection voltage, the battery management system will cut off the whole series charging circuit and stop charging to prevent the single lithium battery cell from being overcharged, which will cause other lithium batteries unable to be fully charged.

In parallel charging of lithium batteries, each lithium ion battery needs equalizing charge, otherwise, the performance and life of the whole lithium ion battery pack will be affected. Common charging equalization technologies include: constant shunt resistance equalizing charge, on-off shunt resistance equalizing charge, average battery voltage equalizing charge, switch capacitor equalizing charge, step-down converter equalizing charge, inductance equalizing charge, etc.

Several problems need to be paid attention to in parallel charging of lithium batteries:

  • Lithium batteries with and without PCM cannot be charged in parallel. Batteries without PCM can easily be damaged by overcharging.
  • Batteries charged in parallel usually need to remove the built-in PCM of the battery and use a unified battery PCM.
  • If there is no PCM in parallel charging battery, the charging voltage must be limited to 4.2V and 5V charger cannot be used.

After lithium ion batteries connecting in parallel, there will be a charging protection chip for lithium battery charging protection. Lithium battery manufacturers have fully considered the change characteristics of lithium battery in parallel before battery production. The above requirement of current design and choice of batteries are very important, so that users need to follow the instructions of parallel lithium batteries charging step by step, so as to avoid the possible damage for incorrect charge.

  • Special charger must be used for lithium battery, or battery may not reach saturation state, affecting its performance.
  • Before charging the lithium battery, it does not need to discharge completely.
  • Do not keep the charger on the socket for a long time. Remove the charger as soon as the battery fully charged.
  • Batteries shall be taken out of electric appliances that have not been used for a long time and stored after they are fully discharged.
  • Do not plug the anode and cathode of the battery into the opposite direction, otherwise, the battery will swell or burst.
  • Nickel charger and lithium charger cannot be used together.

When it comes to the words’ lithium battery’ it’s safe to say that lately, these two words have generated a lot of confusion, fear, and speculation. So, it’s no wonder you might ask yourself, “why on Earth would anyone use Lithium batteries?” But rest assured, we’ve done our homework. At Himax, we’ve dedicated over a decade of our time on, research & development, learning, design, and optimization of our products, to ensure that we always provide customers with safe technology and innovative solutions. Before we can get into what makes our Lithium batteries safe, let’s cover the basics.


Lithium 101
Lithium was discovered in 1817 by Swedish Chemist, Johan August Arfwedson. You might remember seeing “Li,” on the periodic table on your school teacher’s wall, but Arfwedson first called it ‘lithos’, which means stone in Greek. Li is a soft, silvery-white alkali metal and its high-energy density makes it a great choice to give batteries an extra boost.

1. Safety:

LiFePO4 is more chemically stable, and it is incombustible, which means that it is not prone to thermal runaway (and remains cool at room temperature). It can also withstand high temperatures without decomposing, and it is not flammable. The bottom line is, you don’t have to worry about it exploding or catching alight on the job.

2. Sustainable:

LiFePO4 batteries have a longer cycle life, and the fact that they are rechargeable makes them sustainable. In essence, you can keep using a LiFePO4 batter over and over again. LiFePO4 is a nontoxic material and doesn’t give off dangerous or hazardous fumes, which makes it safe for you and the environment too.

3. Long lasting:

A Lithium LiFePO4 battery does not need to be fully charged to use. This means that you can connect several batteries in parallel, without damaging the batteries which are less charged than others. It can also be discharged quickly without damaging the cells either. LiFePO4 batteries have a shallow rate of self-discharge, which means they can be left standing for months and not run out of juice or cause permanent damage. They also have a longer and better life cycle, ranging in the thousands. (2000 cycles).

4. Efficiency:

A Lithium LiFePO4 battery has a much higher charging rate, it charges quicker than other batteries, and charging it is effortless.  It also requires zero maintenance, which means you’ll experience minimal downtime and maximum productivity when you use Lithium LiFePO4 battery tug.  Lithium LiFePO4 batteries are lighter and occupy less space, which makes pushing and pulling a compact tug with a Lithium LiFePO4 battery, ergonomic. Our Lithium LiFePO4 battery is versatile and easily intergrade with many of our tugs. Since the battery is rechargeable and simple to charge, which means they are ready to move when you are.

5. Performance:

Lithium LiFePO4 batteries have an optimal energy density in both volume and weight and have good specific energy, which means the battery can give the necessary power when needed. It’s also worth mentioning that Lithium LiFePO4 batteries have excellent cycling performance too.

Bonus: Battery management system

Our Lithium battery comes standard with a battery management system (BMS) to manage the rechargeable Lithium LiFePO4 battery. How it does this is by monitoring the battery’s state and the cells. It also collects various sets of data to calculate and control the battery’s environment. One of the critical functions of the BMS is to balance the cells to ensure that the battery can perform at its best while protecting it by observing its voltage and temperature to avoid cell failure.

Fishing battery

Fisherman driving a gray and blue bass boat on the lake.

Wondering how to charge a deep cycle battery the right way? You’ve come to the right place!

So you took the plunge and invested in a deep cycle battery. You’re excited about spending endless hours on the water and powering your trusted trolling motor and favorite fishing gadgets. But in order for your battery to continue working for years to come, you’ve got to put in a smidge of work to keep things running smoothly.

Now of course, if you have a lithium deep cycle battery, your maintenance “to do” list is pretty short. Nearly as short as Santa’s naughty kids gift list. That’s because lithium batteries don’t need electrolyte “topping-up”, cleaning, or any of that nonsense that lead-acid batteries require.

However, there is one thing you must do for any battery–even lithium. You must charge it the right way!

Why Do You Need To Charge Your Battery Correctly?

Why does it matter how you charge your deep cycle battery? Well, charging the right way can actually affect your battery’s performance and lifespan. For lead acid batteries, overcharging can ruin them. Leaving them at a partial state of charge can do a real number on them too.

Luckily, those no-nos don’t exist for lithium marine batteries. You can use them past 50% battery capacity without damaging them. And you don’t have to charge them right away after using up your charge. This is super convenient when coming home from a fun but exhausting day out on the lake.

But there are a few things you’ll want to keep in mind when charging a deep cycle battery, even if it’s ionic lithium. Read on to find out how to charge a deep cycle battery the right way!

Cycles of Battery Charging

A deep cycle battery is designed to attain a considerable depth of discharge, and then be recharged to full capacity for many cycles during its lifespan. A typical deep cycle battery cycle would begin with the battery at 100 percent capacity, then drain the battery to between 20 and 50 percent of its original capacity, then recharge to 100 percent.

The normal depth of discharge of your batteries will also affect their lifespan. A battery that is often pushed to 50% depth of discharge will live longer than one that is frequently pushed to a higher depth of discharge. Repeated shallow discharge (5-10%) of a deep cycle battery, on the other hand, correlates to reduced lifespans.

Again, quality deep cycle batteries are designed to be drained and then recharged to full capacity from a practical viewpoint. On the water, you really don’t need to be conservative with your batteries. Drain them, and when you get back to dry ground, recharge them with a charger to automatically restore their full capacity.

How to Charge a Deep Cycle Battery Correctly

Two fishermen driving in a red bass boat on the lake.

Ready to juice up your battery? Here’s how to charge a deep cycle safely and efficiently:

Choose the correct charger type.

It’s a no-brainer that the BEST charger for a deep cycle battery is the one that’s built specifically for its type. That means an ionic lithium battery will charge better with a lithium battery charger.

Sure, it’s possible to “mix-and-match” battery types and chargers. But you run the risk of your charger reaching different voltage limits than your battery can handle. It’s possible to damage your battery, or at the very least, you’ll see an error code and your battery won’t charge.

Also, consider the fact that a correctly-matched charger will help your battery charge faster. For example, ionic lithium batteries can take a higher current. They charge much faster than other types, but only when paired with the correct charger.

So how do you choose the right charger? Simply put, read the charger’s description. It will specify what type(s) of batteries you can use it to charge. For lithium deep cycle batteries, we suggest Ionic single chargers and Ionic bank chargers. Built for lithium LiFePO4 marine batteries, they are smart chargers that supply constant voltage and stop charging once they reach max voltage. Some models may also be used to charge lead acid and AGM batteries.

Onboard chargers for batteries – the options.

Both offer the same set of key advantages:

  • Charges your batteries more quickly and conveniently.
  • Up to four 12V lithium batteries can be charged at the same time.
  • Can be used to charge both lead-acid and AGM batteries.
  • The cable is five feet long.
  • Charge status is shown via colored LEDs.
  • When utilizing Ionic Lithium Batteries, the Ionic Lithium app displays the charge level.
  • Lightweight
  • Affordable

These onboard chargers are perfect for competitive fishermen and boaters. They’re also ideal for anyone looking for the most advanced onboard battery chargers available on the market, and people who hate to wait long for their battteries to charge.

Portable chargers for batteries – the options.

Sometimes, installing an onboard charger is impossible or impracticable. Take for example, a tiny boat with limited storage, or a trolling motor-powered kayak or canoe — in these cases, you’ll probably need a portable battery charger. It’s probably impractical otherwise, and that’s okay — you’ve got options.

  • 12v Portable Chargers
  • 24v Portable Chargers

Both of these chargers are single bank, and offer the same basic functions. These “Smart” chargers for 12V LiFePO or lead-acid batteries are constant current, constant voltage (CCCV). When 14.6V is achieved, these smart chargers cease charging.

Both are great options for fishermen and boaters who need portable battery charging for their trips.

Choose the right charger voltage/amps.

Once you know what type of charger you need, you need to pick one with the right amount of voltage and amps. For example, a 12V charger is compatible with a 12V battery. Within the 12V battery category, you can choose from different charge currents (i.e. 4A, 10A, 20A).

To choose the right amount of amps, check the amp hour (Ah) rating of your battery. Make sure the amp rating isn’t higher than the amp hour rating of your battery. Using a charger with an amp rating that is too high can damage your battery.

You can also use a bank charger to charge multiple batteries at once.

Charge in the right conditions.

Did you know that high and low temperatures can affect your marine battery? Lithium batteries are the most resilient of the bunch. You can charge them at temperatures between -4°F – 131°F (0°C – 55°C) with no risk of damage. But the optimum charging temperature for Ionic Lithium Batteries is above freezing. If you need to charge your battery below freezing temps, no need to fret. Our 12V 300Ah battery is a beast of a battery and comes equipped with a heater, so no more worries about freezing temperatures!

Two fishermen driving in a bass boat on the lake as the sun sets behind trees in the background.

How to Charge a Deep Cycle Battery Correctly (& Safely): Step by Step

Once you have the right charger, charging your battery is a cinch. Here’s what to do, step by step:

  1. Make sure the battery terminals are clean.
  2. First, connect the red (positive) cable to the red terminal. Then connect the black (negative) cable to the black terminal.
  3. Plug in the charger. Turn it on.
  4. If using a smart charger, you can “set it and forget it”. It will stop charging on its own. Ionic lithium chargers feature Bluetooth capabilities that let you check charge status on your phone. Other chargers, like those used for lead acid batteries, may require you to set a timer and disconnect it once it’s charged.
  5. To disconnect, unplug the charger. Remove the black cable, then the red one.

Now you know how to charge a deep cycle battery safely and correctly. Here’s to many more adventure out on the water!

Solar Battery

Solar Battery

Are you wanting to use solar power off grid? If so, you’re going to need off grid solar batteries–and they’d better be reliable.

If you use a grid-tied or hybrid system, it’s possible to run your solar without batteries. But as soon as you go off the grid, batteries become an essential part of your setup. Without them, you can’t store solar energy for use at a later time. You know, times when the sun’s not shining.

And what if you invest in solar batteries, only for them to malfunction, or run out of energy earlier than expected? Well, if the skies are dark, unfortunately your house or RV will be too.

So save yourself the trouble. Keep reading to discover the pros and cons of each battery type so you can choose the best one!

Off Grid Solar Batteries Aren’t Just for Camping

Years ago, solar batteries had their habitat in remote campsites and mountaintop cabins. Today, they’re still essential for boondocking and dry camping but with “grid defection” on trend, solar setups are making their way towards many towns and cities.

People are going off grid in places where grid power is available. They’re building eco-friendly tiny houses that completely rely on solar power. Others are installing solar panels on rooftops as backup power in places where the grid’s frequently unreliable. Some are saving big money by using solar only, and relying on the grid as a backup.

So now, more than ever, off grid solar batteries need to be reliable, long-lasting, and efficient. But not all batteries are created equal. Below, we’ll discuss the different types of off grid solar batteries so you can decide which is best for you.

boondocking with solar

What Are the Best Solar Batteries?

There’s no denying that lead acid batteries have been used in off grid solar setups for a long time. They’re the “OG” (original) batteries, and in the early days of solar energy, you wouldn’t see a setup without them.

But technology has evolved since then. So while lead acid batteries still get the job done, we wouldn’t say they’re the best off grid solar batteries on the market. They may be the most affordable upfront, but their benefits don’t go far beyond that.

Now each battery type has its pros and cons. Let’s compare the top contenders for off grid solar batteries, specifically lead acid, AGM, sealed gel, and lithium. These are the four most popular solar batteries available today and that’s why each is worth discussing. So let’s get to it!

Lead Acid Batteries

Lead acid batteries have been around for over 150 years. Most folks who use them as off grid solar batteries do so because of their low up-front cost.


  • Low cost
  • Good for short-term backup solar power


  • Short lifespan (3-5 years). Can be shorter if overcharged or not maintained correctly.
  • Require maintenance (watering, cleaning).
  • Contain toxins that may harm the environment.
  • Aren’t leak-proof and must be stored in a ventilated area.
  • Not ideal for remote off-grid sites that aren’t visited frequently, because of maintenance needs.
  • Usable capacity is 50%.

Sealed Gel Cell Batteries

Sealed gel cell batteries have electrolytes stored in gel form. This prevents them from spilling. They are similar to AGM batteries.


  • Can tolerate long periods without being charged.
  • Low self-discharge rate.
  • Longer cycle life than AGM batteries.
  • Maintenance free.


  • Medium-high cost.
  • Not suitable for constant use in remote places (where replacement is difficult).
  • Charges slowly.
  • Short lifespan (2-5 years).
  • Limited ability to deliver peak power.
  • 50% usable capacity.

AGM Off Grid Solar Batteries

AGM stands for absorbed glass mat. These are similar to gel cell batteries and are sealed.


  • Low maintenance
  • Good for intermittent use, such as in a vacation cabin
  • Performs better than gel batteries when delivering peak power
  • Spill-proof, will not leak
  • Low self-discharge rate


  • Medium to high cost
  • Not suitable for constant use in remote places (where replacement is difficult).
  • Susceptible to overcharging.
  • Short lifespan( 4-6 years). May be shorter if overcharged.
  • 50% usable capacity.

Lithium Off Grid Solar Batteries

LiFePO4 lithium batteries are the newest off grid solar battery type. They’re currently the most reliable battery on the market for solar setups. Here’s why:


  • Longest lifetime of any battery type.
  • Protected from overcharging or undercharging.
  • Eco-friendly, toxin-free, and will not leak.
  • Maintenance-free.
  • Lowest lifetime cost of any battery type.
  • Fastest charging battery type.
  • Great for both long-term, short-term, and intermittent use
  • Does not need to be replaced often; good for remote locations.
  • Most energy-efficient of all battery types.
  • Usable capacity is 80-100%, the most of any battery type.
  • Best battery for hot and cold climates.


  • Higher up-front cost


Which Solar Batteries Should You Choose?

Everyone’s energy needs are different. Lead acid or gel type batteries may work if you’re looking to test a solar setup short-term to see if it’s a right fit for you.

But when you consider efficiency, reliability and lifetime cost, it’s clear that lithium comes out on top as the best contender among all off grid solar batteries. So don’t let the slightly steeper up-front cost rain on your parade! Keep things sunny (and your electricity running smoothly) by powering your setup with lithium.

Equalizing Charge

Know how to apply an equalize charge and not damage the battery.

Stationary batteries are almost exclusively lead acid and some maintenance is required, one of which is equalizing charge. Applying a periodic equalizing charge brings all cells to similar levels by increasing the voltage to 2.50V/cell, or 10 percent higher than the recommended charge voltage.

An equalizing charge is nothing more than a deliberate overcharge to remove sulfate crystals that build up on the plates over time. Left unchecked, sulfation can reduce the overall capacity of the battery and render the battery unserviceable in extreme cases. An equalizing charge also reverses acid stratification, a condition where acid concentration is greater at the bottom of the battery than at the top.

Experts recommend equalizing services once a month to once or twice a year. A better method is to apply a fully saturated charge and then compare the specific gravity readings (SG) on the individual cells of a flooded lead acid battery with a hydrometer. Only apply equalization if the SG difference between the cells is 0.030.

During equalizing charge, check the changes in the SG reading every hour and disconnect the charge when the gravity no longer rises. This is the time when no further improvement is possible and a continued charge would have a negative effect on the battery.

The battery must be kept cool and under close observation for unusual heat rise and excessive venting. Some venting is normal and the hydrogen emitted is highly flammable. The battery room must have good ventilation as the hydrogen gas becomes explosive at a concentration of 4 percent.

Equalizing VRLA and other sealed batteries involves guesswork. Observing the differences in cell voltage does not give a conclusive solution and good judgment plays a pivotal role when estimating the frequency and duration of the service. Some manufacturers recommend monthly equalizations for 2–16 hours. Most VRLAs vent at 34kPa (5psi), and repeated venting leads to the depletion of the electrolyte, which can lead to a dry-out condition.

Not all chargers feature equalizing charge. If not available, the service should be performed with a dedicated device.


Learn what you can do to prevent a Li-ion battery to fall asleep.

Li-ion batteries contain a protection circuit that shields the battery against abuse. This important safeguard also turns the battery off and makes it unusable if over-discharged. Slipping into sleep mode can happen when storing a Li-ion pack in a discharged state for any length of time as self-discharge would gradually deplete the remaining charge. Depending on the manufacturer, the protection circuit of a Li-ion cuts off between 2.2 and 2.9V/cell.

Some battery chargers and analyzers (including Cadex), feature a wake-up feature or “boost” to reactivate and recharge batteries that have fallen asleep. Without this provision, a charger renders these batteries unserviceable and the packs would be discarded. Boost applies a small charge current to activate the protection circuit and if a correct cell voltage can be reached, the charger starts a normal charge. Figure 1 illustrates the “boost” function graphically.

booost1.jpg Figure 1: Sleep mode of a lithium-ion battery.

Some over-discharged batteries can be “boosted” to life again. Discard the pack if the voltage does not rise to a normal level within a minute while on boost.

Do not boost lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer. Copper shunts may have formed inside the cells that can lead to a partial or total electrical short. When recharging, such a cell might become unstable, causing excessive heat or show other anomalies. The Cadex “boost” function halts the charge if the voltage does not rise normally.

When boosting a battery, assure correct polarity. Advanced chargers and battery analyzers will not service a battery if placed in reverse polarity. A sleeping Li-ion does not reveal the voltage, and boosting must be done with awareness. Li-ion is more delicate than other systems and a voltage applied in reverse can cause permanent damage.

Storing lithium-ion batteries presents some uncertainty. On one end, manufacturers recommend keeping them at a state-of-charge of 40–50 percent, and on the other end there is the worry of losing them due to over-discharge. There is ample bandwidth between these criteria and if in doubt, keep the battery at a higher charge in a cool place.

Cadex examined 294 mobile phones batteries that were returned under warranty. The Cadex analyzer restored 91 percent to a capacity of 80 percent and higher; 30 percent were inactive and needed a boost, and 9 percent were non-serviceable. All restored packs were returned to service and performed flawlessly. This study shows the large number of mobile phone batteries that fail due to over-discharging and can be salvaged.


Compare battery energy with fossil fuel and other resources

Lifting off in a large airplane is exhilarating. At a full weight of almost 400 tons, the Boeing 747 requires 90 megawatts of power to get airborne. Take-off is the most demanding part of a flight and when reaching cruising altitude the power consumption decreases to roughly half.

Powerful engines were also used to propel the mighty Queen Mary that was launched in 1934. The 81,000-ton ocean liner measuring 300 meters (1,000ft) in length was powered by four steam turbines producing a total power of 160,000hp (120 megawatts). The ship carried 3,000 people and traveled at a speed of 28.5 knots (52km/h). Queen Mary is now a museum in Long Beach, California.

Table 1 illustrates man’s inventiveness in the quest for power by comparing an ox of prehistoric times with newer energy sources made available during the Industrial Revolution to today’s super engines, with seemingly unlimited power.

3000 BC Ox pulling a load 0.5hp 370W
350 BC Vertical waterwheel 3hp 2,230W
1800 Watt’s steam engine 40hp 30kW
1837 Marine steam engine 750hp 560kW
1900 Rail steam engine 12,000hp 8,950kW
1936 Queen Mary ocean liner 160,000hp 120,000kW
1949 Cadillac car 160hp 120kW
1969 Boeing 747 jet airplane 100,000hp 74,600kW
1974 Nuclear power plant 1,520,000hp 1,133,000kW

Table 1: Ancient and modern power sources

Large propulsion systems are only feasible with the internal combustion engines (ICE), and fossil fuel serves as a cheap and plentiful energy resource. Low energy-to-weight ratio in terms of net calorific value (NCV) puts the battery against the mighty ICE like David and Goliath. The battery is the weaker vessel and is sensitive to extreme heat and cold; it also has a relatively short life span.

While fossil fuel delivers an NCV of 12,000Wh/kg, Li-ion provides only between 70Wh/kg and 260Wh/kg depending on chemistry; less with most other systems. Even at a low efficiency of about 30 percent, the ICE outperforms the best battery in terms of energy-to-weight ratio. The battery capacity would need to increase 20-fold before it could compete head-to-head with fossil fuel.

Another limitation of battery propulsion over fossil fuel is fuel by weight. While the weight diminishes when being consumed, the battery carries the same deadweight whether fully charged or empty. This puts limitations on EV driving distance and would make the electric airplane impractical. Furthermore, the ICE delivers full power at freezing temperatures, runs in hot climates, and continues to perform well with advancing age. This is not the case with a battery as each subsequent discharge delivers slightly less energy than the previous cycle.

Power from Primary Batteries

Energy from a non-rechargeable battery is one of the most expensive forms of electrical supply in terms of cost per kilowatt-hours (kWh). Primary batteries are used for low-power applications such as wristwatches, remote controls, electric keys and children’s toys. Military in combat, light beacons and remote repeater stations also use primaries because charging is not practical. Table 2 estimates the capability and cost per kWh of primary batteries.

Capacity (alkaline) 1,150mAh 2,850mAh 7,800mAh 17,000mAh 570mAh
Energy (single cell) 1.725Wh 4.275Wh 11.7Wh 25.5Wh 5.13Wh
Cost per cell (US$) $1.00 $0.75 $2.00 $2.00 $3.00
Cost per kWh (US$) $580 $175 $170 $78 $585

Table 2: Capacity and cost comparison of primary alkaline cells. One-time use makes energy stored in primary batteries expensive; cost decreases with larger battery size.

Power from Secondary Batteries

Electric energy from rechargeable batteries is more economical than with primaries, however, the cost per kWh is not complete without examining the total cost of ownership. This includes cost per cycle, longevity, eventual replacement and disposal. Table 3 compares Lead acid, NiCd, NiMH and Li-ion.

Specific energy (Wh/kg) 30–50 45–80 60–120 100–250
Cycle life Moderate High High High
Temperature performance Low when cold -50°C to 70°C Reduced when cold Low when cold
Applications UPS with infrequent discharges Rugged, high/low temperature HEV, UPS with frequent discharges EV, UPS with frequent discharges
Cost per kWh ($US)
Load leveling, powertrain
$100-200 $300-600 $300-600 $300–1,000

Table 3: Energy and cost comparison of rechargeable batteries. Although Li-ion is more expensive than Lead acid, the cycle cost may be less. NiCd operates at extreme temperatures, has the best cycle life and accepts ultra-fast charge with little stress.


Power from Other Sources

To reduce the fossil fuel consumption and to lower emissions, governments and the private sector are studying alternate energy sources. Table 4 compares the cost to generate 1kW of power that includes initial investment, fuel consumption, maintenance and eventual replacement.

Fuel type Equipment
to generate 1kW
Life span Cost of fuel
per kWh
Total cost
per kWh
$500/kW (20kW battery
costing $10,000)
2,500h (repl. cost $0.40/kW) $0.20 $0.60
($0.40 + $0.20)
ICE in vehicle $30/kW
4,000h (repl. cost $0.01/kW) $0.33 $0.34
($0.33 + $0.01)
Fuel cell
– portable
– mobile
– stationary
$3,000–7,500 2,000h
$1.85 – 4.10
$1.10 – 2.25
$0.45 – 0.55
Solar cell $12,000, 5kW system 25 years $0 ~$0.10*
electric grid
All inclusive All inclusive $0.20

Table 4: Cost of generating 1kW of energy. Estimations include the initial investment, fuel consumption, maintenance and replacement of the equipment. Grid electricity is lowest.

* Amortization of investment yielding 200 days of 5h/day sun; declining output with age not included.

Power from the electrical utility grid is most cost-effective. Consumers pay between $0.06 and $0.40US per kWh, delivered with no added maintenance cost or the need to replace aging power-generating machinery; the supply is continuous. (The typical daily energy consumption per household in the West is 25kW.)

The supply of cheap electricity changes when energy must be stored in a battery, as is the case with a solar system that is backed up by a battery and in the electric powertrain. High battery cost and a relatively short life can double the electrical cost if supplied by a battery. Gasoline (and equivalent) is the most economical solution for mobility.

The fuel cell is most effective in converting fuel to electricity, but high equipment costs make this power source expensive in terms of cost per kWh. In virtually all applications, power from the fuel cell is considerably more expensive than from conventional methods.

Our bodies also consume energy, and an active man requires 3,500 calories per day to stay fit. This relates to roughly 4,000 watts in a 24-hour day (1 food Calorie* = 1.16 watt-hour). Walking propels a person about 40km (25 miles) per day, and a bicycle increases the distance by a factor of four to 160km (100 miles). Eating two potatoes and a sausage for lunch propels a bicyclist for the afternoon, covering 60km (37 miles, a past-time activity I often do. Not all energy goes to the muscles alone; the brain consumes about 20 percent of our intake. The human body is amazingly efficient in converting food to energy; one would think that the potato and sausage lunch could hardly keep a laptop going for that long. Table 5 provides the stored energies of calories, proteins and fat in watt-hours and joules.