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  1. #1
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    Lipo. single or paralell

    My buddy has 2 2200 25c 2s packs and 2 1550 3s 25c packs. Can he run them 1 battery at a time, or do they need to be ran in parallel to boost the amp rating? How many amps does the mini VXL pull?
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  2. #2
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    they can be run individual but why not just drive it in parallel?
    keep your mouth closed and let your eyes listen

  3. #3
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    do you know how many amps the vxl draws?
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  4. #4
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    nope sorry but you can always google it
    keep your mouth closed and let your eyes listen

  5. #5
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    I have seen a thread from a long while ago where someone measured the current draw from the motor and it his 60 amps a few times.
    HPI Savage LOSI Mini/MicroT, MRC Traxxas Revo VXL

  6. #6
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    the 2s can provide 55 amps and the 3s can provide 39. so can they be ran by themselves?
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  7. #7
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    Quote Originally Posted by Brushless Moose
    the 2s can provide 55 amps and the 3s can provide 39. so can they be ran by themselves?
    yep by there selves and parallel are the same thing
    keep your mouth closed and let your eyes listen

  8. #8
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    no, if you run in parallel you boost your c rating.
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  9. #9
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    Quote Originally Posted by Brushless Moose
    no, if you run in parallel you boost your c rating.
    ????????? parallel is the exact same as single just more mAh
    keep your mouth closed and let your eyes listen

  10. #10
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    and by adding more mah, the continuous am rating of the packs go up.
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  11. #11
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    ..........
    Last edited by LowTEC; 07-24-2009 at 05:44 AM.
    3905,3708,7108
    5805,17/58,REM,VXL,1/8

  12. #12
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    Guys... Let's do some simple math to understand LiPos and C ratings:

    2 batteries here:
    #1: 2 packs - 2200 25c 2s (2S = 7.4v)
    #2: 2 packs - 1550 25c 3s (3S = 11.1v)

    1C represents the capacity of the battery
    ...so 1C = 2200mAH for that battery #1
    ...so 1C = 1500mAH for that battery #2

    Amps provided by batteries is a simple multiplication:
    #1: 25C x 2200mAH (or 2.2A) = 55 Amps @ 7.4V
    #2: 25C x 1550mAH (or 1.55A) = 38.75 Amps @ 11.1V

    Running them in parallel, doubles capacity (mAH):
    #1: 2x 25C x 2200mAH (or 2.2A) = 110 Amps @ 7.4V
    #2: 2x 25C x 1550mAH (or 1.55A) = 77.5 Amps @ 11.1V

    (Note: Peak Current: 326A / Continuous Current: 52A)
    This means ESC will only draw that much. You battery might provide more than enough Amps safely is what that mean... but you're not going to get more Amps out of it unless you go with another ESC. Since you're running in parallel, the Amps drawn from each battery is split in 1/2 (26A each max continuous)), meaning a cooler battery, safer draw, and less stress on batteries...

    Running them in series, doubles voltage!! (V):
    #1: 2x 25C x 2200mAH (or 2.2A) = 55 Amps @ 14.8V
    #2: 2x 25C x 1550mAH (or 1.55A) = 38.75 Amps @ 22.2V

    --> I think this is a big NO?!! Exceeds 14.4V spec !!!!!!!!!!!
    DO NOT RUN LiPo's in Series!!!


    SPECS of ESC:
    http://www.traxxas.com/products/elec...7108_specs.htm

    Batteries can be overkill... don't fry your ESC.

    Keep Specs in mind when getting batteries.
    Last edited by mombojombo; 07-24-2009 at 10:13 AM.

  13. #13
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    he has no intentions of running them in a series. he is worried that the 39 amps cont. will not be enought and may harm the pack. (55 for the 2s pak.) That is why I am asking, do the packs need to be ran in parallel to boost the c rating, or is 39 cont. enough for the tiny ESC. (55 for 2s)?
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  14. #14
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    Quote Originally Posted by Brushless Moose
    he has no intentions of running them in a series. he is worried that the 39 amps cont. will not be enought and may harm the pack. (55 for the 2s pak.) That is why I am asking, do the packs need to be ran in parallel to boost the c rating, or is 39 cont. enough for the tiny ESC. (55 for 2s)?
    If you run in parallel, you double the Amp capacity and rating.

    Running them in parallel, doubles capacity (mAH):
    #1: 2x 25C x 2200mAH (or 2.2A) = 110 Amps @ 7.4V
    #2: 2x 25C x 1550mAH (or 1.55A) = 77.5 Amps @ 11.1V

    ESC will only draw 52A from both cells when run in parallel.
    So each cell will only draw 26A... way below the capability of the batteries.
    Hence, running in parallel will work for either cells safely and you have a nice cool battery that's not stressed much at all (i.e. cool battery).
    Last edited by mombojombo; 07-24-2009 at 10:52 AM.

  15. #15
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    Quote Originally Posted by Brushless Moose
    . . . do the packs need to be ran in parallel to boost the c rating. . .
    I think this is where the confusion sets in. The c rating of a pack does not and can not change. Runninng the batteries in parallel does not increase the c rating, it increases the available capacity. Available output amperage is battery capacity in mAh, divided by 1,000 and multiplied by the pack's c rating.

    Your question is valid, though. You do want to make sure that the available amperage is high enough that you don't over stress the packs. As long as the pack (or packs) are not getting too warm by the time you hit the Lipo safety, you should be ok. I usually go as conservitive as possible, just to be sure, so I always run two packs in parallel. I have four of the Reedy 2s 1800mAh 20c packs, so that is 36 amps constant. With only one pack, the thing will still do a backflip from a dead stop, and it doesn't get warm at all, but I just like having two in the truck.

  16. #16
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    so I was right the whole time haha
    keep your mouth closed and let your eyes listen

  17. #17
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    Yep, you'll double your run time. 2 2200 should get you over a 40 min average run time.

  18. #18
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    Cainam nailed it. i meant it doubled the amp output of the packs.
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  19. #19
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    WOW!!!! A thread where everybody was right, and everbody is happy!!!

    \o/ CHEERS WILDLY!!!!!

    Doughnuts and pizza for everyone!!!

    Now, what toppings do we get. . . ?

  20. #20
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    pepperoni and black olives. mmmmmmm

    on my truck I am running two 3s lipos in parallel.. for amazing current on demand and good run times..

  21. #21
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    so, running them single is ok?
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  22. #22
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    this is like pulling teeth! LOL
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  23. #23
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    Quote Originally Posted by Brushless Moose
    so, running them single is ok?
    yes its ok! lol
    keep your mouth closed and let your eyes listen

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