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  1. #1
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    Parallel with different mhA?

    Hi,

    I try to find on the forum my answers, but I didn't. With the parallel adapter, can we use 2 differents mhA?

    I have the original 1200mhA and another 1600mhA. Can I combine both to have 2800mhA or this can damage the battery?

    Thanks

  2. #2
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    You'll be fine in parallel
    When the stock 1200 starts losing power that's it
    Don't expect to go longer

  3. #3
    RC Turnbuckle Jr. mike-susieq1's Avatar
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    nope you cant because the 1200mah would die and over discharge before the 1600mah would leading to a fire/ or ruin your battery. its best to use 2 the same specs.
    DEU 8:18 ESV

  4. #4
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    When attaching two packs in parallel you create a single battery system... this means you basically create a single pack that has the capacity of both packs combined. One WILL NOT drain before the other, they will both drain at the same rate and deplete at the same time; assuming that the resistance in both packs is nearly identical.
    Whatever it is I just typed... could be wrong.

  5. #5
    RC Turnbuckle Jr. mike-susieq1's Avatar
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    I tried that running 1200 and 1600 so did my friend same terrain at that same time and the 1200 pack got real hot almost too hot too touch while the 1600 pack was warm only, when i tested the 1200 voltage was way lower than the 1600 pack was. pack was just about dead when trying in the car but the 1600 ran more. guess something was wrong with the packs then
    DEU 8:18 ESV

  6. #6
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    Could have been different discharge rates, and perhaps you were pulling too much from one of the batteries and they need to be the same cell-count!

    For instance, if you have a 3s 5000mah 20c battery in parallel with a 3s 1500 50c battery, it should be treated like a 3s 6500 20c. Hope that makes sense.

    Sounds to be like you either had a low discharge rate battery, OR mis-matched cells - that would make for extreme heat!

  7. #7
    RC Turnbuckle Jr. mike-susieq1's Avatar
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    thinking it may have had a bad cell because i think like 15 cycles later the battery gave out lol, the 1600 still working fine though it has signs of weaking though.
    Stock battery 1200 series 1 i got about 75-100 cycles only out of it at about 1-1.5amps which is a bit much at 1.5amp for that battery.
    DEU 8:18 ESV

  8. #8
    RC Turnbuckle Jr. jimbo74's Avatar
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    Quote Originally Posted by krallopian View Post
    Could have been different discharge rates, and perhaps you were pulling too much from one of the batteries and they need to be the same cell-count!

    For instance, if you have a 3s 5000mah 20c battery in parallel with a 3s 1500 50c battery, it should be treated like a 3s 6500 20c. Hope that makes sense.

    Sounds to be like you either had a low discharge rate battery, OR mis-matched cells - that would make for extreme heat!

    NEVER RUN LIPOS THAT ARE NOT IDENTICAL like that.... you are asking for major problems if you do

  9. #9
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    Quote Originally Posted by koolyce View Post
    Hi,

    I try to find on the forum my answers, but I didn't. With the parallel adapter, can we use 2 differents mhA?

    I have the original 1200mhA and another 1600mhA. Can I combine both to have 2800mhA or this can damage the battery?

    Thanks
    The only thing is as soon as the 1200mah battery losses power you should stop, cos the 1600mah is going to last a few mins longer.
    You don't want to be running much after the stock 1200 cos it's not ideal to over drain them
    1600mah is goin to last a few mins more so it'll be wise to use your judgement when you see the rc slowing down

  10. #10
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    Lots of incorrect info in this thread suggest most of you do a lot more reading before handing out advice

    Cheers
    Slash Platinum
    Xerun 150 / Tenshock SC401 3500kv

  11. #11
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    I'd say just don't do it. You really need to run identical pack together. I always heard the running non identical packs is asking for trouble. Save some worry and just run single packs till you can buy two packs of the same kind. Besides, a battery swap only takes like 20 seconds tops.
    Dye-no-mite Pow-er Go Fast, Wirrrrr Screeeech BOOM

  12. #12
    RC Turnbuckle Jr.
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    Stay with identical packs either with nimh or Lipo but I would upgrade to Lipo when you can

  13. #13
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    Quote Originally Posted by 50togo View Post
    Stay with identical packs either with nimh or Lipo but I would upgrade to Lipo when you can
    I would like, but I'm new and I don't know which model of lipo will fit and which charger I need. Also, I don't know how to charge it and it seems to me "dangerous" than Nimh.

  14. #14
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    Series - Cell numbers can be different but the capacity should ALWAYS be the same - 2s lipo 2200mah 3s 2200mah making it a 5s 2200mah
    Parallel - ALWAYS same cell numbers and capacity can be different just as long as the voltage left in the lipos are within 0.2v of each other. 2s 2200mah + 2s 2000mah making it a 2s 4200 mah lipo...
    HPI Vorza | Traxxas Summit | 1/16 Traxxas E-Revo

  15. #15
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    C ratings need to be the same for either configuration.
    Whatever it is I just typed... could be wrong.

  16. #16
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    If you can't get a definitive answer, I'd say just don't do it

  17. #17
    RC Turnbuckle Jr.
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    Quote Originally Posted by koolyce View Post
    I would like, but I'm new and I don't know which model of lipo will fit and which charger I need. Also, I don't know how to charge it and it seems to me "dangerous" than Nimh.
    here are some good 2 cell lipo batteries http://www.spcracing.com/index.php?productID=107 and check out an icharger for a good charger. following simple guidelines lipo batteries are fine

  18. #18
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    Quote Originally Posted by funnya1b2c3 View Post
    If you can't get a definitive answer, I'd say just don't do it
    The thing is, there is a definitive answer and you can get it. It is just that all the people who don't have sufficient education in the area of electricity and electronics are confusing the issue, supplying answers that are wrong because they just don't know any better.

  19. #19
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    Differing discharge rates only matter when you go above the lowest discharge capability.

    So again, a 3S 5000mah 20c and a 3s 2000mah 50c in parallel, can work together no problem, UNTIL You ask for more than 20c, then the problem arises. If you have a motor that wants 60amps constant, but your lowest battery discharge rate will not allow it, you have big problems.

    And so... if you don't understand what you're doing, it's best to just get two identical packs and run them in parallel. Get two Traxxas 2s 2200mah 25c batteries, and you'll be fine outputting up to 110 amps all day, more than any 1/16 can ask for imo.

  20. #20
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    Back OT;

    The series 1 will draw more current than it normally does when connected in parallel. The added amp draw is what made it heat up. The C-rating on 2/3a cells is not very high relatively.

    Quote Originally Posted by 1600mah 2/3a cell specs
    High capacity (1600 mAh) and high discharge rate (9C-12C) for super performance
    0111001101101001011001110000110100001010

  21. #21
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    All in all, just stick with the same packs. Some education in physics and electronics is needed to understand the concepts. It's high school physics at the least to understand...
    HPI Vorza | Traxxas Summit | 1/16 Traxxas E-Revo

  22. #22
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    Basic Ohms Law (V=IR)

    Those that do not understand it, should be running similar specced packs in parallel


    Cheers
    Last edited by crusey; 11-16-2012 at 05:57 PM.
    Slash Platinum
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