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  1. #1
    RC Enthusiast
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    Question dual batteries and pinion gear

    Hey All,

    probably a newb question - i just picked up a 1/16 e-revo vxl and a second nimh battery (7.2V, 1200mah). I have a series and a parallel battery adaptor. My plan was to run the batteries in series to get extra power/speed. I noticed a sticker saying that the pinion gear must be installed if running dual battery packs but then in the manual it suggest only using the pinion gear when speed runs are your goal and not to do too much hard acceleration etc.

    What I'm wondering
    - how risky is it to run dual nimh (7.2V) batteries in series without the high speed pinion gear?
    - if I do run dual batteries in series and think i might be doing hard accelerating and braking is it better to have the high speed pinion gear installed or not?
    - if I run a single 3s lipo (or two 3s lipos in parallel) would I need the high speed pinion gear then as well? same problems with accelerating / braking?

    Thanks for any and all help and advice.

  2. #2
    RC Turnbuckle Jr.
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    it is risky running even in series with the speed pinion! (23t) so i would not run it with the 28! running in series is pretty hard on it but can be done . if you don't have a temp gun pick one up and keep an eye on the temps
    the more voltage creates more heat so even with 3 cell lipo gear down
    Last edited by 50togo; 10-25-2012 at 10:56 AM.

  3. #3
    RC Racer
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    Well, stock out-of-the-box you have an 28T pinion and 50T spur.
    That's too high of a gear ratio for anything other than 2S LiPo and 7.2V NiMH.

    The "High Speed" pinion is 23T, so that would raise your final gear ratio - equals less strain on your motor and ESC, but also less top speed and more torque.
    However, running 3S or NiMH in series will greatly make up for "less top speed" and will launch the car as a missile nonetheless with 23/50.

    If you go with 28/50 on 3S/Series NiMH, your motor/ESC will just heat up FAST.
    Greetz, JEREMY.

    RCblog.nl Summit●ERevo2●X-MAXX

  4. #4
    RC Competitor
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    We run a 28/50 set up with 7.2 in series w/o heat issues many times. But, you can't put a lot of strain on the motor causing it to suck up amps and get hot. We've done 28/45 set ups with smaller tires. Watch your temps for sure--about every minute twice, then 5 minutes twice, then 10 minutes or so until you're sure you don't have a heat issue when pushing the envelope. A higher speed ratio(like 28/45) puts strain on the motor when accelerating hard, for example.

  5. #5
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    The manual actually states that running stock packs in series should only be done on smooth surfaces for short periods of time.

    • The High Speed dual-battery battery and gearing
    configuration is for high-speed running on smooth
    surfaces only. Avoid repetitive hard acceleration to prevent
    overstressing the motor, speed control and batteries.
    • Failure to install the appropriate gearing can cause failure
    of the motor, speed control and batteries when running the
    model on 12 NiMH cells. See the gearing chart on page 24 for
    more information about properly gearing your model.
    • Make certain both batteries are fully charged before
    installing them in your model. Installing a fully charged pack
    and a partially discharged pack may lead to overdischarging
    and damage to the partially discharged battery.
    • Do not mix batteries of different brands, chemistries or
    capacities. Only genuine Traxxas batteries are approved for
    dual-battery use in this model.
    • Stop running your model and allow it to cool if the speed
    control’s thermal overload protection activates or if the
    motor temperature exceeds 200 F.
    Whatever it is I just typed... could be wrong.

  6. #6
    RC Competitor
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    Quote Originally Posted by Jimmie Neutron View Post
    The manual actually states that running stock packs in series should only be done on smooth surfaces for short periods of time.

    • The High Speed dual-battery battery and gearing
    configuration is for high-speed running on smooth
    surfaces only. Avoid repetitive hard acceleration to prevent
    overstressing the motor, speed control and batteries.
    • Failure to install the appropriate gearing can cause failure
    of the motor, speed control and batteries when running the
    model on 12 NiMH cells. See the gearing chart on page 24 for
    more information about properly gearing your model.
    • Make certain both batteries are fully charged before
    installing them in your model. Installing a fully charged pack
    and a partially discharged pack may lead to overdischarging
    and damage to the partially discharged battery.
    • Do not mix batteries of different brands, chemistries or
    capacities. Only genuine Traxxas batteries are approved for
    dual-battery use in this model.
    • Stop running your model and allow it to cool if the speed
    control’s thermal overload protection activates or if the
    motor temperature exceeds 200 F.
    I know, I know--but it's just not as fun--LOL vs blowing the tires off(literally) every now and then. I would say about 70% of our running is done at 14.4V, pushing both trucks hard, until they get hot of course.

  7. #7
    RC Turnbuckle Jr.
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    maybe time to upgrade to a better esc like the mmp and neu 1110 1/y motor!

  8. #8
    RC Enthusiast
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    Thanks for all the advice guys - can I just check - if I'm running 2s lipos in parallel would I be ok to leave the stock pinion and spur?
    I guess I'm really asking - what's the most i can squeeze out of her without changing the pinion :-)

  9. #9
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Yes, but check temps.
    The extended run time can lead to excessive heat build up.
    Whatever it is I just typed... could be wrong.

  10. #10
    RC Enthusiast
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    ahh ok great! thanks mate.

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