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  1. #1
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    Battery Size Limitations?

    I am thinking about getting 2 Venom 9.6V 5000mAh 8-Cell Hump Pack NiMH Batteries for my E-Maxx Brush-less. I do not want to go the LiPo route and was curious of what everyone thought about these batteries or other recommendations.

  2. #2
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    Any particular reason you do not want to go the LiPo route?
    Always get a 2nd Opinion!

  3. #3
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Brushless power is going to be hard on a NiMh battery... they probably will not stand up to the abuse for long.

    As far as the size goes... if you use some other form of hold down, only length and width really hold you back.
    Whatever it is I just typed... could be wrong.

  4. #4
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    Mugs - I am unsure if the risk's out-weigh the ability they have of burning my house down in case of failure. I know they should be fine, especially if I keep them in a steel box while charging, and the ability of them going bad if drained while in use, which kills them dead. I guess I am going the safe route. Less I have to worry about.

    Jimmie Meutron - Yeah I figured I would need a different setup to fit the double piggy-backed batteries. I just wasnt sure if I could go higher then 8.4v sense they are so rare. But I guess so long I don't exceed the 22v(?) capacity it?

  5. #5
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Right... just don't exceed the voltage rating of the ESC.

    I am in no way trying to talk you into LiPo, but LiPo fires only happen when you seriously abuse the pack. As long as some general rules and guidelines are followed, there is absolutely no risk involved with LiPo.
    Whatever it is I just typed... could be wrong.

  6. #6
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    Ah I see I did not realise the ESC would have a different power voltage rating. Thank you for the peice of info!

    No no your fine, I have not totaly ruled out LiPo, just for now I will wait. Maybe they will find a way to rid that small, um, flaw?

    Big Ooops!! Just realized I spelt your name wrong in the previous post. I do apologies.

  7. #7
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    The "flaw" is a part of the chemistry... even NiMh can explode if mistreated.

    No apology needed.... but it is accepted.
    Whatever it is I just typed... could be wrong.

  8. #8
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    Very true. I am sure I will convert, but for now, I am going to try the 9.6v 5000Mah and see how it goes.

    I did read somewhere it has equal power to a 4s LiPo...

  9. #9
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    its almost equal to lipo 4s but dont last as long. nihm batts drop its volts in few speed passes and start to show of slowing down.
    humay has left the building, peace.

  10. #10
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Am I missing something??

    4S LiPo = 16.8v fully charged.
    So how does 9.6v compare??

    EDIT:
    NM... read the entire thread again. When I read "try the 9.6v" I took it as one battery, not two.
    Also, an 8 cell NiMh will top out at around 12.8v. So if you are going to use them in series, be sure that the ESC will handle 25.6v!
    Last edited by JimmyNeutron; 10-03-2012 at 10:35 PM.
    Whatever it is I just typed... could be wrong.

  11. #11
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    Oh wow, I had no idea. It was just what I read. I haven't done any extensive research by any means yet.
    Find the droids you were looking for.

  12. #12
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    Well, in theory your first response is correct, I would have to get 2 9.6v to equal 1 4s LiPo, but wouldn't I need 2 4s Lipo's for the brushless?
    Find the droids you were looking for.

  13. #13
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    There are not many systems that will handle 8S!
    If you want to run 4S voltage, getting two 2S batteries and running them in series would give you about the same run time; only cheaper... usually. I say usually because in most cases, two 2S batteries are going to be cheaper than 2 4S batteries when you are trying to match up to similar capacities.

    Since that part was confusing for even me, let me give an example:

    2S 5000mAh batteries in series = 4S 5000mAh ... quick cost search: about $15 each
    4S 2500mAh batteries in parallel = 4S 5000mAh ... quick cost search: about $25 each
    Whatever it is I just typed... could be wrong.

  14. #14
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    Ok, so for the E-Max Momba Brushless I would only need 1 LiPo battery, not 2?
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  15. #15
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    I think you could use a single LiPo... but I believe the minimum suggested voltage is 4S or equivalent. Because of the way Traxxas wired the ESC from factory, you would need to solder up a jumper or change the wiring on the ESC.
    Running a single battery will also throw off weight balance and handling.

    In my explanation above, two batteries were used...
    running in "parallel" and "series" includes a minimum of two batteries.
    Whatever it is I just typed... could be wrong.

  16. #16
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    So get this, I just checked the Traxxas website, and they have a chart for the E-Maxx Momba Monster Brushless Edition (which I have) and this is what it says, "65mph & beyond - Twin 3S LiPo = 22.2V Max" So that means I can use twin 9.6V NiMh ?
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  17. #17
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    Find the droids you were looking for.

  18. #18
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Input voltage (cells): 18 NiCad/NiMH 6s LiPo (max: 25.2 volts)

    You would only be using 16 cells of NiMh with two of the batteries mentioned in series.
    Whatever it is I just typed... could be wrong.

  19. #19
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    I don't get it, i think i'm reading it wrong.
    Find the droids you were looking for.

  20. #20
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    The packs you say you want to use in post #1 are 8 cell packs.
    In order to get enough voltage to move your RC properly you will need 2 of these packs.
    When used in series, battery packs will give you double the voltage.... which is double the cell count.
    This would make your batteries for your RC have 16 cells of NiMh.
    The ESC is rated for up to 18 cells of NiMh.
    Whatever it is I just typed... could be wrong.

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