Choosing The Right Battery For Your Electric Vehicle Build

Many a hacker has looked at their scooter, bike, or skateboard, and decided that it would be even better if only it had a motor on it. Setting out to electrify one’s personal transport can be an exciting and productive journey, and one that promises to teach many lessons about mechanical and electronic engineering. Fundamentally, the key to any build is the battery, which has the utmost say in terms of your vehicle’s performance and range. To help out, we’ve prepared a useful guide on selecting the right battery for your needs.

One Chemistry To Rule Them All

Batteries come in all shapes and sizes, and a variety of different chemistries that all have their own unique properties and applications. When it comes to small electric vehicles, it’s desirable to have a battery with a low weight, compact size, plenty of current delivery for quick acceleration, and high capacity for long range.

30 years ago, options were limited to lead acid, nickel cadmium, and nickel metal hydride batteries. These were heavy, with low current output, poor capacity, and incredibly slow charge times. Thankfully, lithium polymer batteries have come along in the meantime and are more capable across the board. Offering huge discharge rates, fast charging, light weight and high capacity, they’re undeniably the ultimate choice for a high performance electric vehicle. They’re also wildly popular, and thus cheap, too!

There are some hangups, however. It’s important to keep all the cells in a pack at the same voltage in order to avoid cells back-charging each other. This can cause damage to the pack, or even explosions or fire. Maintaining the battery voltages to avoid this is called “balancing”. It can be handled in various ways, depending on the exact style of battery you’re using, as we’ll cover later.

Additionally, lithium batteries do not like being over-discharged. As a rule of thumb, it’s a good idea not to let your batteries drop below 3.0 V per cell. Failure to keep this in check can lead to ruining a pack, hurting its maximum capacity and ability to deliver current.

There are thankfully ways around these issues, and which ones you use depends on the battery you choose for your application.

But Which Battery, Exactly?

It’s one thing to say you should use a lithium polymer battery, but they come in a wide variety of flavors for different applications. Which type you use will depend on the vehicle you’re trying to build, your goals for performance and range, and your own abilities and desire to build or buy.

A Word About Voltage and Capacity

Lithium polymer cells are rated nominally at 3.6 V, and their capacity is measured in amp-hours or milliamp-hours. When looking at a pack for your electric vehicle, you’ll want to note the total pack voltage and the capacity. Higher voltages are good for higher performance vehicles and improved efficiency, as more power can be delivered at lower currents with less losses. However, this requires stacking more cells in series, which can add cost, and also requires more expensive controllers and charging solutions. Higher capacities are good for longer range, and are often achieved by stacking more cells in parallel.

Homebrew 18650 Packs

Building your own pack can be a lot of work, but also quite rewarding. Source: [Adam Bender]
Many home-built electric vehicles are created by hackers with a strong DIY ethos, and that often extends to the individual components, too. In these circles, many elect to create their own battery solution, relying on the popular 18650 cell as the basis for the pack. These can be readily harvested from laptops, power drills and other sources, or picked up from recycling centers, as well as bought new. The cells have a strong metal case and are mechanically quite robust. However, the individual cells are limited to a maximum of around 3600 mAh, despite what you may read on eBay.

Due to the limited capacity of the individual cells, many packs for e-bikes and electric vehicles stack several cells in parallel. 18650-based packs are often referred to with designations like 10S4P, indicating there are 4 parallel sets of 10 cells each in the battery. Such a battery would have a nominal voltage of 36 V, with a capacity of between 10-14 Ah depending on the particular 18650 cells used.

To assemble a pack, soldering is a poor option due to the danger of heating the cells, and the results are typically weak from a mechanical standpoint. The most reliable way is through the use of a spot welder to connect the cells with metal strips from terminal to terminal. Some elect to build their own spotwelders, but if you’re just trying to get your vehicle rolling, this would be considered as unnecessary yak shaving. They can be bought instead. Either way, once the cells are connected, individual leads can be added to the various cells for connection to a battery management system, or BMS – a board that monitors the individual voltages of the cells in the pack. This board accepts a connection from a wall charger that sits at the battery’s maximum voltage, and handles charging and balancing to keep the battery in good health, and also protects against over-discharge and over-current events. All this can then be wrapped up in the enclosure of your choice. Thanks to the metal case of the individual cells, often a simple plastic wrap can suffice.

Homebuilt 18650 packs are useful if you want to customise a pack to your own exacting specifications, or if you wish to build on the cheap with recycled parts. However, there’s plenty of work involved, and you may find that the money you spend on tools to get the job done outweighs the savings along the way.

Pros: can be cheap, customizable voltage, capacity and packaging
Cons: significant work involved, can be heavier than other options

eBay E-bike Packs

A typical eBay listing for an eBike battery. Convenient, but current output can be quite limited.

For those uninterested in building their own packs, there is another option. With the proliferation of e-bikes around the world, parts are now readily available to those wishing to strike out on their own. A wide variety of battery packs for e-bikes are now available, most of which are built with the exact same tools and techniques as the homebrew packs mentioned above. The major benefit of these ones, however, is that someone else has done all the hard work!

Consisting of 18650 cells laced together in various configurations to suit different applications, they’re available in a range of voltages from 36 V-60 V and occasionally higher, with large capacities for long range. The vast majority come with an integrated battery management system and a charge connector already hooked up, and many sellers will throw in a suitable wall charger, too.

They’re a great choice if you want a high-capacity pack that’s ready to go, off the shelf, without a lot of fuss. One drawback, however, is that many of these packs are somewhat hobbled from the factory in terms of current output. While the average 18650 is capable of delivering significant current without breaking a sweat, it’s not uncommon to find a 36 V battery limited to a relatively low output of 15 A by the integrated BMS. This is fine if you’re building a 200 watt e-bike to cruise by the beach, but if you’re trying to build a quick scooter to tear along gravel paths with a 500 watt motor, you’re going to run into problems with the BMS cutting the power. This can often be hacked around, but it takes the shine off the convenience of these ready-to-go packs.

Pros: Ready to go, complete solution, fairly robust
Cons: Can have issues with current limits, limited packaging options

RC Flight Packs

High-end RC packs really do look the business, but be sure to handle them carefully!

Lithium polymer batteries have been a boon for the model flight hobby, with their high power density and ability to deliver huge gobs of current at a moment’s notice. These typically use pouch cells, wherein the electrolyte is contained in a plastic pouch without a hard outer shell. These have great packing efficiency and are much lighter than metal cased cells, but are also much more delicate. The cells tend to swell a little over time, and are easy to damage if squeezed or pierced. This can lead to fires or explosion, and thus such cells must be installed in such a way to protect them against accidental damage.

Designed for the demands of high-powered RC aircraft, these cells are capable of current delivery at an immense rate, with 20 times the total battery capacity, or 20C, being common. High-end packs are readily available that can top 75C, which for a 2 Ah pack, is 150 A. This makes these RC packs useful for high-performance applications, where large motors are drawing several kilowatts of power under load. The tradeoff is in storage, with RC packs generally being fairly large for a given capacity, due to the size of the electrodes needed to sustain such high current draws. These packs usually only come as packs of up to 6 cells in series; often you’ll need two or more ganged up to reach a more suitable voltage for your electric vehicle where 10 S to 12 S is usually more desirable.

The high performance packs also come at a high cost, particularly compared to 18650 cells which have the benefits of economies of scale behind them. They also come without any protection or battery management systems. When used in an electric vehicle, they can either be removed after use and hooked up to a standard RC charger, or wired up to a BMS for a more contained solution for charging. Either way, it’s important to pay attention to balancing and maintenance, as these high current packs are more prone to fire and explosions than others.

Pros: Huge current delivery, light weight
Cons: Price, must be handled delicately, needs a charging solution fitted

Power Tool Packs

Often, these packs are a great choice for a quick test build, as you’ve already got them lying around. The connectors can be a pain, though.

Lithium polymer cells have also revolutionized the power tool industry, and made cordless tools far more practical than ever before. Most tools on the market use 18 V, or five-cell packs, with different manufacturers using 18650 cells or pouch cells depending on their tastes. They usually come in a hard plastic case with a proprietary connector to hook up to a certain brand of tools. Inside, there’s usually a basic BMS to handle cell balance and to shut things down if anything goes wrong.

Power tool packs have the benefit of being highly rugged, as they’re designed to withstand the construction environment. Tools can be quite power hungry, so current delivery is usually pretty solid, too. A drawback is that these packs can be quite expensive, because manufacturers want to lock consumers into their own tool ecosystem. Interfacing with them can be a pain too, due to the proprietary connectors. Common workarounds involve nails and tape, 3D printing, or simply gutting old tools. Charging is simply handled by plugging into the standard charger, with the batteries having the benefit of being easily hot-swappable by design. As they’re often already lying around, they can be a great way to test out an electric vehicle build before investing in a more suitable permanent battery solution.

Pros: Easily hot-swappable, you’ve already got some, rugged
Cons: Expensive, not particularly space efficient, proprietary connectors

Summary

We’re blessed to have more battery options now than ever before, and as capacities and power outputs continue to rise, we continue to see new and more innovative electric vehicles than ever before. By weighing the relevant factors, and choosing carefully, you can pick the optimum solution for the special vehicle in your life. Hopefully, you’ll find this guide useful to point you in the right direction with your own builds, and when you’re done, be sure to drop us a line!

43 thoughts on “Choosing The Right Battery For Your Electric Vehicle Build

  1. “however. It’s important to keep all the cells in a pack at the same voltage in order to avoid cells back-charging each other. This can cause damage to the pack,” is actually true for all battery types of batteries, be it lead acid ones, Lithium, or NiMH ones. If you have two or more cells in series, then balancing will extend the life of the battery.

    Now, lead acid batteries have been around for so long that it is just industry standard not to have cell balancing on them. Same for NiMH ones.

    Lithium cells are far from the only type in need of balancing.

    Not like a heavily unbalanced led acid pack has its own set of problems when charging. (Also, the smallest of the cells is usually the one that fails.)

    Now, it is debatable if cell balancing is truly needed if one stays sufficiently away from the outer limits of max/min charge, while also taking some care to ensure that the cells are reasonably close in capacity to start with.

    Though, a flying capacitor based cell balancing system could efficiently handle minor imbalances, though this would be load dependent.

    A balancing system that simply burns away the power from the highest charged cells is obviously not going to be as energy efficient, but at least it protects the cells from overcharging….

    1. NiMH and lead-acid self-balance to an extent, because if they are overcharged the extra charging is converted to heat, and if it is charged slowly enough in the final phase the battery is not damaged.

      Li-ions also convert extra charge beyond 4.20 V into heat, but a bit too fast.

    2. The obvious difference being that most of the other chemistries will tolerate a subtle overcharge, just burning the excess away as heat. You float a lead acid’s voltage slightly higher than would theoretically be needed for a full charge, and the cells that get full first will slowly drain off the excess while the others catch up.

      Lithium batteries with a large imbalance will just overcharge, and are very likely to catch fire eventually.

      Suggesting that cell balancing might be unneeded is pretty questionable without a lot of caveats. If you have good per-cell monitoring you could probably skip it for the most part, and only do a balance manually when required. Without monitoring, though, if a cell does have any sort of problem, and there’s not a per-cell LVC, or balancing shunt (which acts as a soft LVC, assuming the currents are reasonable), there’s potential to overcharge a cell and start a fire.

      1. There are two things that overcharging a wet cell lead-acid will do:
        1) Promote corrosion of the plates (this takes a LONG time to be noticeable though…)
        2) Boil off some electrolyte

        2) is easily fixable by putting water back in the battery. Which is why SOP for forklift batteries is to:
        Once a week, apply an “equalization” charge that is well above float voltage. This ensures that all cells are fully charged and also that the bubbling of the electrolyte ensures it’s mixed evenly and does not stratify.
        Monitor battery electrolyte levels. Most forklift batteries now have a built-in monitor that blinks red if the electrolyte gets low
        When the blinkenlight turns on, charge battery to full, add water, charge again. (You need to charge first because the electrolyte will expand when charging).

        As others have pointed out, doing this with li-ion = BOOM.

      2. “Suggesting that cell balancing might be unneeded is pretty questionable without a lot of caveats.”

        Yes it is. And why I am of the opinion that even lead acid battery packs should have cell balancing.

        Now the consequences of not leveling a lead acid pack is less severe then a lithium one. But that doesn’t mean that we can’t get better life expectancy out of the lead acid pack if we balance it.

        (And a flying cap based leveling system can also increase the packs capacity, since we can more efficiently drain all cells, while ensuring that as much of the energy as possible actually powers the end application. Restive based balancing systems doesn’t do this, since they just load the larger cells a bit more and burn that energy as heat. Now flying capacitor based balancing systems are though a bit limited when it comes to power… So not all that adequate for most vehicles.)

    3. This really is why I’m not terribly keen on permanently welding up or soldering together packs of cells. I have observed in dry cells, wet cells, NiCad and NiMh, the tendency of the positive end cell in a pack to discharge first, the negative end one to be discharged much less, perhaps only 50% sometimes, then others in approx ratio between the first and last. This is with all other things being equal, some more or less matched cells, no internal resistances way off in the sigmas. Then which cell dies first is kinda dependent on charging methodology. Fast charging, you might have the most negative cell die first, why? It’s done the least work! But it has also got the least charge, it’s depleted to 50% but might only get 10% by the time the charger kicks out, so it starts at 60%, goes down to 20%… doesn’t get full charge again… so eventually spends most of its time “dead-ish” so gets made more deaderer. However, normal rate slow charge, and typically left on that rate or float for a while afterwards, it comes up to 100% every charge, and being the least discharged is the healthiest. The least healthy then is the most positive one doing all the work, getting discharged flat every time. So first mortality is either the most positive end cell, from maxing its cycle life, or a random fail in the middle of the pack due to differences in IR or manufacturing. Middle cells will also fail more often if they are snuggly in the middle of a pack, and cannot dissipate heat as well as those on the ends, it’s heat related stress/wear.

      So, I prefer when possible to use decent holders, or make screw fastened connections, so I can rotate the batteries in a pack. I also try to give the packs long float charges as often as possible between quick charges. To me, the argument that welded packs are more reliable is kinda moot if they’re gonna die sooner from cells turning up their toes and pining for the fjords. The contact oxidation problem is much mitigated if you’re into it every few months to rotate the batteries, and the mechanical stability problem is easily solved by mounting precautions and strapping things down with tape if you have to. Heat shrink is cheap enough nowadays you can easily shrink the pack, or use a blow moulded PET bottle, and cut it off every change.

      1. Batteries don’t work that way. In a series string, there’s no difference in loading between the cells, whether at the positive or negative end.

        The mid pack heat build-up is actually the only real effect you mention.

          1. Well, I couldn’t explain why, since that’s just not how it works. I can only think of a couple causes of a consistent cell imbalance.

            Some bad BMS designs may be running off of the balance connections of only 1-2 cells, so in some cases if it’s allowed to sit for a long time in a low SOC you might see a tendency for certain cells to go flat earlier, but that’s a fairly specific circumstance, and if the balancing circuitry is working correctly, it should rarely be an issue. (just don’t run the pack down to 10% and leave it sit that way for a long time)

            Also, it’s possible that a bad balance circuit may actually imbalance the pack. If you’re doing all of your testing with the same BMS or balancing charger design, that may be the culprit.

            Other than that, your guess is as good as mine.

            With my anecdotal evidence against yours: I’ve looked at the cell voltages on my quadcopter batteries at end of charge lots of times, and have never noticed any consistent pattern to which cell is lowest. It’ll usually be consistent on a given pack, based on which cell is weakest, but there’s never been any apparent pattern between packs, nor can I think of any reason there should be.

      2. There is no physical way for the “positive end” of a series to discharge first, because it’s the same current that goes through every cell. If you have observed such an effect, it’s either because of heat distribution or observation bias.

        1. Well it was some dozen years ago someone first told me that swapping dry cells around when you’d “worn out” the batteries in it gave you an extra day or two use, and having that confirm on way too many occasions for chance I started measuring those and I’d get typically .850 V and 1.150 V on a pair of AAs. You know what though, this is pretty much always with electronic loads, they probably have dropout voltages 0.7 to 1.2 V or so at minimum, or whatever the cutoff of their SMPSU converter is, with a pure resistive load you’d be able to drain the cells to flat line zero and this would not be noticed most likely.

          Anyway, some conditions to this behaviour, has to be recently discharged, leave something sitting dead on shelf 6 months and it’s not going to show up, cells probably self discharged low enough that no effect will be observed. It’s not recovery effect either, since you can say have a remote go dead, swap cells around, continue using for a couple of days, or have remote go dead, stop using, forget to buy new batteries 3 days in a row, try swapping the cells in frustration and get 2 days about the same. Or at least you wouldn’t notice a large difference in time to deplete for second time from recovery.

          Maybe heating is part of it, I’m thinking that you don’t actually get the same voltage at all points in the pack so that’s more watts for same current, maybe this warms up the deader cell so its chemically more efficient or something.

          1. Your thinking on the different voltages at different points of the pack is incorrect. There’s no difference between the first and last one in a string, since there’s no common reference. All of the cells do the same current, based on the total series voltage, and the resistance of the load.

            For example, if you have a fully charged 2S lipo feeding into a load that draws 1A, it’ll be discharging at 8.4W, and each cell will be contributing 4.2W, since they’re at 4.2V, each. You don’t get 8.4V from the top battery, and 4.2 from the bottom one.

    1. Mostly overhyped, IMO.
      I had some for my bike before. They tend to be heavier than most of the lithium ion chemistries, and they seem to be more prone to balance issues in my experience.
      In theory, they’re safer, since they’re less prone to thermal runaway problems, but they still need proper battery management if you want them to have a decent lifespan.

      Also, anywhere that you have large amounts of stored energy and burnable plastics and electrolytes, there’s still the potential for fire.

      1. LiFe batteries also don’t like cold – they work, but they can’t be charged properly below freezing temperatures so they’re not suitable for car batteries. Regular lead-acids work as long as they’re not frozen solid, but the lithium cell’s internal resistance rises so high that the charging voltage overshoots the safety limits.

        1. I’m using them as they like heat.. Where I am it goes from about 2c at the lowest to about 40c ambient(And higher inside the packs).. Where most other lithium chemistry get upset and start to fail, these continue to work.

          1. Edit: Oh.. And I have about 15kWh(Going to be upgrading to 20) of them.. With propper BMI..
            In an Electric Car..
            Heavier, but safer and more resilient to deeper discharges and other abuse without major damage.

      2. I disagree.
        I am using selected but unbalanced A123 LiFePO4 battery packs as starter batteries for all of my (1000cc) motorbikes, directly charged by the alternators with no extra electronics whatsoever. They’ve been abused in any way you can imagine, but still hold their promise after 10 (?) years of service for the oldest pack. I don’t even charge them during north German winters while the engines will reliably start for the first spring ride. Not to mention the weight benefit over Pb…

  2. The lithium versions of lead acid batteries look like a pretty good bet for power to weight. They can cost a few pennies though. Even motorbike ones are surprisingly light weight in comparison to the car version. As for stacking lots of cells. There’s nothing to stop you charging them in a different configuration than you drain them. Even charging each cell one at a time and switching between them and then reconnecting them all again when they are all topped up. Could be good for something like wind or solar power where you can’t get enough current to charge them all at once.

  3. Those ebay e-bike packs. yeah.
    No problem to buy pack with 18650 with 4000mAh :-)
    Some chinese cells are maybe 3000mAh but with 0.2C etc.
    2000mAh is great value for those packs, per cell.

  4. I keep seeing the term “lithium polymer” used in the is article to refer to 18650 cells. 18650 cells predated lithium polymer chemistry and I doubt anyone manufactures an 18650 in lithium polymer. They are typically lithium Ion. Polymer versions are typically used when the battery needs to conform to a non-cylindrical shape.

    18650 cells became popular in notebook computers due to having the highest energy to weight ratio. Not sure if that is still true.

  5. It’s kind of important to pay attention to current ratings for 18650 cells as well. A lot of the higher energy cells in the 3000mAh+ range have pretty low current ratings even in high end brand-name cells, so you would need a few of them in parallel just so you’re not thrashing them. Stuff that’s intended to be used in a laptop with a couple hours of runtime only needs to output a couple amps, and many laptop or random salvage 18650 aren’t rated for any more than that. (if your cells only do 3A, you’re going to need >10 in paralllel for a modest bike motor, never mind something powerful.

  6. Buying random, high-energy-density battery packs on ebay scares me to death. There’s more than enough cases of poorly manufactured battery packs catching fire to make me wary of cheap packs from non-mainstream sellers and manufacturers. I am interested in doing something like DIY powerwall, but not sure where to source affordable, high quality cells.

    1. Alarmhookup (now batteryhookup) on ebay is a good source if you’re in North America. They salvage cells from new-old-stock equipment, the cells have been sitting around unused so they’re still in great condition. In some cases their cells are individually labelled with testing results.

      I bought from them multiple times and they’re my go-to source for cheap, genuine cells.
      https://batteryhookup.com/

  7. The C-ratings for RC packs are pretty much pure BS. Relatively speaking, a higher C rating pack of a given brand is likely capable of higher currents, but very few of them can actually reach their ratings for more than a couple seconds, even when they’re listed as “continuous”

  8. Just as you shouldn’t blindly use a RasPi for every computing problem, you shouldn’t blindly use lithium for every battery project. There’s a reason why lead-acid and nimh cells are still sold by the billions. Each chemistry has its advantages and disadvantages.

    If you want simple and cheap, and weight and range aren’t critical, lead-acids do fine. Millions of fork lifts and golf carts are using them every day.

    If you want long life and reliability, nicads or nimh are great. They will outlast lithiums by quite a bit, as long as they aren’t abused. I have 30-year-old nicads and 20-year-old nimh modules from early Toyota Priuses and scrapped GM EV-1s that still work great.

    Lithiums come in a bewildering number of sizes, shapes, and performances. If you throw together something without knowing what you’re doing, the results are likely to be fun, but short-lived, and end unpleasantly.

    More on balancing here: http://sunrise-ev.com/balancer.htm

    1. NiCads are no longer available to consumers in the EU due to the hazardous substance restriction limiting the amount of Cadmium in battery products to less than 0.002%. The only exemption is medical and safety equipment.

  9. I think the 21700 would be best energy density and high amp batteries are readily available molicel 21700p42a 4200mAh 35 amp CDR PULSE (<80°C) 40 AMP or if 10 amps are enough current capacity and want longer run time Samsung 50E 5000mAh 9.8AMP CDR BUT 3 extra mm diamater per cell adds up when talking about 40 calls. 4P10S

  10. so, question on capacity:

    how do I best determine how many amp hours I should build a pack for? I can know the motor/controller wattage, but that seems to give me numbers that suggest crazy large battery packs. I want to run 850-1kW on an e bike build and hopefully get 20-30 mile range between charges

    1. Rick, you use watt-hours per mile to estimate range. An electric bicycle uses 5-10 WH/mi. A car uses 200-300 WH/mile. Other vehicles fall somewhere in between, (determined by weight, speed, and aerodynamics).

      1. Electric bikes vary a lot more than that in energy use. I think the range you give is definitely too low for most of them. You might get that kind of range on one where you’re doing half of the work.

        I would estimate closer to 10wh/km (16WH/mi) for a typical one being run moderately for commuter duty around here. I guess there might be a lot less hills where you are though, so YMMV.

        Even small differences in the way you ride, and the current limiting on your controllers can make a massive difference to your energy consumption.

        riding around at 20km/h, you’ll probably use half the energy you would at 32km/h.

        riding my longtail cargo bike fairly fast, I use around .5Ah/km (15-20 wh/km) on my 10s lipo. It is a bit on the heavy side, not very aerodynamic, and I do have quite a lot of hills on my commute. That said, if I slow down to 25km/h, and go a little easier on it taking off from lights, I can probably bring it down near half that.

    2. what you will also need to consider is the peak discharge capability of the cells in the pack. I have been doing an ebike build and figured a 13S6P pack made up of reclaimed 2000mAH Cells would be adequate for my range requirements but they would not be able to deliver the peak currents required during acceleration. To cope with that I need to double my pack size ( I should have done the sums first and just went a smaller motor) My other option is to limit the power from the controller.

      Reclaiming cells BTW is a PITA need to charge and test each cell and match similar cells in the pack. Makes for a huge time investment increased if you go and build your own spot welder…..

    1. I finally got my Rad2Go scooter running. I went with SLA because of price and will be using it in wet FL. weather and off road! The SLA can handle a bit more heat as well when ambient is 95* then pulling my 200# around. I’m pushing a 24 V 26 amp motor at 36 V and it hauls butt for just having rear drum brakes, going to add a front brake soon! If you can find a Rad2go scooter grab it, they can hold like 300# and are built pretty good. I got a cheap motor controller for it and hoping it holds up, max temps I’ve seen on motor is like 120* and 110* on battery, MC was like 98-99* in 90* ambient temps!

  11. *sigh* ok here is a better breakdown

    Lead Acid
    Starting batteries
    Deep cycle batteries
    “Marine”/”RV”/”Golf cart”
    Forklift
    AGM

    Nickle (I dont know the techical differences on these)
    NiCd
    MiMh

    Lithium [what chemistry are we talking? NCA, LCO, NMC, LMO, LFP, LTO?]
    (lithium danger)
    LiPo Rc batteries high discharge for power applications prone to fire
    (lithium caution)
    LiIon various chemistrys encompases 18650 batteries
    (lithium safe)
    LiFePO4 lower power density but much safer and voltage makes it a drop in replacement for lead acid batteries
    (lithium exotic)
    im just thinking of LTO cells here, spendy, low power density, but crazy safe

    There are 2 classes of 18650 cells based on chemistry
    Power cells rated for ~10C+ discharge rates, used in Teslas, EVs, Tools, Vapes
    Storage cells rated for 1C discharge rates, used in Laptops, Lights, Other lower power applications

    Im making a portable power pack for an inverter and with storage cells i can count on 2.7w peak draw per cell (144w peak out of a 52 cell pack) i need to run a 300W inverter so im having to build 2 sets of batteries to be able to feed the inverter [although with a very good run time]

    with power cells starting at 18w peak draw per cell i only need 16 cells to reach the same peak power as 2; 52 cell batteries. [although with less runtime]

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