RC Car Lipo Batteries Differences

• 

  pegaxs on 29/12/2021 - 21:33

  +7

  C is the discharge rating. ie: how fast the battery can empty its energy out.

  mAh is the capacity or storage amount.

  S refers to how many cells are set up and in what configuration. S is Series, P is paralleled.

  • 

    jizmo on 29/12/2021 - 23:44

    yes but I think the dump rate is over a short period of time. Like a boost C= 40 @ 5 seconds if I can remember right

• 

  pjetson on 29/12/2021 - 22:14

  I think the thing to understand with almost all sellers is that their quoted battery capacities are basically fiction.

  • 

    brendanm on 29/12/2021 - 22:25

    Not really the case in the world of lipos.

  • 

    wombat81 on 29/12/2021 - 22:48

    If you buy random Chinese brands from banggood/Ali/eBay then yes, but if you buy reputable brands like ovonic, Turnigy etc their ratings are reliable.

    • 

      [Deactivated] on 30/12/2021 - 13:35

      I wouldn't say Turnigy are reliable. I've turned many Turnigy batteries into puffy bags of fun by mashing the throttle the first few times I've used them. Seems to be especially bad on their nanotech range.

  • 

    pjetson on 30/12/2021 - 08:11

    These sellers do not reveal the type of cells they use, so the specs are impossible to check without running tests on the actual packs. I would question why one pack is quoted at nearly twice the capacity of another, with the higher capacity pack being much cheaper. Sounds fishy to me.

    • 

      brendanm on 30/12/2021 - 08:58

      These sellers do not reveal the type of cells they use

      I think you are getting liion and lipo confused. These are pouch lipo batteries, not liion packs made up of 18650s or similar.

      • 

        pjetson on 30/12/2021 - 12:09

        Thanks for your concern, but I'm not confused. A cell is a single unit, and a battery is a collection of cells. These batteries are 3S, which means three cells in series.

        • 

          brendanm on 30/12/2021 - 16:26

          @pjetson: Lol, that's not what you meant at all. You said "the sellers do not reveal which type of cells they use".

          • 

            pjetson on 30/12/2021 - 18:23

            @brendanm: By type of cell, I clearly meant manufacturer and specs, so that their claims could be checked, which is what we are discussing.

            I'm sorry that you think you know more than me about what I meant. You seem to be trying hard to prove something, but it's not clear what it is.

            • 

              brendanm on 30/12/2021 - 20:14

              @pjetson: You didn't "clearly" mean anything. None of these packs ever have the manufacture of the actual pouches stated, it's probably Xinjiang hianginj lipo pouch happy light limited or similar. From my experience, from several hundred $ race packs, to HobbyKing packs, all reach their stated capacity. If you are running 1/10 scale, pretty much anything will do.

              I'm sorry that you think you know more than me about what I meant. You seem to be trying hard to prove something, but it's not clear what it is.

              You're telling the story?

    • 

      furyou on 30/12/2021 - 10:26

      +1

      Exactly. The ovonics is way higher spec than the 1st nxe, yet cheaper. Then way way cheaper than the nvision. It's more than 'brand markup'

• 

  jaybo on 30/12/2021 - 11:18

  the C rate is also linked to the capacity.

  a 40C, 4000mah pack charges/discharges at the same rate as a 20C, 8000mah pack (160 Amps, in both cases - 40 x 4Ah = 160 and 20x 8Ah = 160)

  for just bashing around - as long as the battery you choose can provide the Amps that your car/plane/boat/quad/whatever will draw (most brushless systems will have this listed somewhere) then just grab whatever… the quality differences between lipos aren't huge imho, outside of the risk of the pack or one of the cells being faulty.

  for racing with cars, there's some rules around requiring hard cases to avoid them getting punctured and catching fire (there used to be requirements for them to be approved by a specific governing body but i'm not sure if that's still the case)

  • 

    furyou on 30/12/2021 - 12:44

    That's interesting, never thought of it that way. I see esc rating not motor in A
    So 60A esc, then I only need a battery to provide 60A
    Then a 8000mah pack I can even use a 10C ?

    • 

      jaybo on 30/12/2021 - 13:06

      in theory - yep!

      double check that the ESC rating is peak and not average (this is more of a thing in cars… flying things generally have a much smoother current draw) and you probably want some degree of buffer, but you'd be hard pressed to find an 8Ah 10C pack anyway :D

      • 

        furyou on 30/12/2021 - 14:06

        I got the rh818 cobra, it's a cheapie so not sure how much you can trust it. But glad to know I can buy the cheapest battery at whatever size. Was going to look at 5000mah. They all seem to be at least 20C anyway.

    • 

      brendanm on 30/12/2021 - 20:18

      You want to match the esc to the motor, the motor is the thing drawing the current. The match the battery appropriately. A motor than can draw 80amps, will kill a 60amp esc, the esc is not a limiter.

• 

  tanksinatra on 30/12/2021 - 11:38

  What brands are known to work well after say a year?

  If you treat them badly none will. Lipos really depend on how you treat them. I've seen some die after <10 cycles.
  I've had bad experiences with Hobbyking brands (Zippy Compact, Turnigy, Turnigy Nano-tech) - most of them died pretty quick. The only one I'd recommend would be the Turnigy Graphene which still does ~40C discharge after three years.

  I'm currently trying the 4S Ovonic batteries. They perform well and seem to meet their rated capacity but it's too soon to tell.

  Maintaining Lipo batteries is a bit of an art-form. I'd recommend:
  - Never charge above 4.2v
  - Charge at 1C, never exceed 2C
  - Never exceed the discharge rating on the cell.
  - Don't go below 3.6v resting voltage.
  - Store at 3.8v.

  • 

    furyou on 30/12/2021 - 12:47

    I got these Infinity Power - Pro3 Battery Charger
    https://www.hobbyone.com.au/infinity-power-pro3-battery-char…

    I guess if I set up the specs and 1C then I'm fine for charging.
    How do you manage the rest? If you use the car halfway (not flat) how do you know what the battery is?

    When you say Store at 3.8v., does that mean every day, or only if I'm not using for a week+?
    And I assume that involves setting the charger to charge halfway?

    • 

      tanksinatra on 30/12/2021 - 13:40

      How do you manage the rest? If you use the car halfway (not flat) how do you know what the battery is?

      I have an on-screen display that shows me the voltage, power and mah drawn. It is also displayed on the screen of my controller.
      If you don't have that you can buy little buzzers on ebay that alarm after a certain voltage. Just plug them into the balance lead.

      Keep in mind that load voltages are not the same as resting voltages.

      When you say Store at 3.8v., does that mean every day, or only if I'm not using for a week+?

      Depends how vigilant you are. Ideally you want to minimize the time spent at 4.2v. I'd probably draw them down to storage voltage if I'm not using them for a week+.

• 

  wombat81 on 30/12/2021 - 11:51

  The key is to have a decent, dedicated lipo charger that balances cells and has a storage charge mode so that you can store them safely between uses.

  • 

    furyou on 30/12/2021 - 15:04

    I got Infinity Power - Pro3 Battery Charger https://www.hobbyone.com.au/infinity-power-pro3-battery-char…
    Not sure the lipo features yt, only used for nimh so far.