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Thread: Question Guys,

  1. #1
    RC Racer
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    Question Guys,

    Hey,

    So I have been loving my Summit, most amazing RC car there is, best of all, I have been racing my friends nitro trucks: TMaxx, Muggy etc... and have destroyed them off road. In fact, I went off road with my buddy tonight who own a new T-Maxx, and I was able to go up everything several times, and he almost made it up once. Sad thing is, he was working on his T-Maxx (nitro) half the time just trying to keep it running, putting gas in it, flipping it right side up etc.. I LOVE THIS Summit!!! Nothing has been able to compare to it.

    My question is, tonight, after running it strong, all the sudden there was a drastic change in power and speed, it slowed to a bear minimum. Then eventually the motor stopped all together, though the lights stayed on and steering was working just fine. So, I thought to myself, I guess the batteries are dying, normal behavior. Odd thing was, I didn't hear my lva going off in my EVX-2. Well, I carried it into the garage, and was curious to see what the voltage was on my Onyx charger for the batteries. One battery showed 6.58 volts, and the other one showed 7.45 volts.

    I know I am ignorant on this subject, learning as I go, but how does this work? I may have voltage but I have run through all my mah? Or am I wrong? Should the truck still run considering I have so much voltage?

    I took the shell off the truck, and my EVX-2 was blinking red, not solid green like it usually is with the Lipo batteries in it. By the way, for those that dont know, I am running spc's 8000mah lipo batteries.

    Any help would be greatly appreciated.

  2. #2
    RC Competitor
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    sounds like the batterys are done and need to be recharged.

  3. #3
    RC Turnbuckle Jr. Wolfslash16's Avatar
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    My guess would be the motor, but I'm not sure. Just what it sounds like to me. I don't have lipos.
    Sl2sh Slayer Summit Sl4sh Teton/Rally T-Maxx Pnde

  4. #4
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    Your pushing the one lipo pretty close to low voltage. What is your LVA set at? My cheapo ebay ones are factory set at 3.0v. Boo 3.0v! SHould be set to 3.2 or 3.4v.

    Does your summit have the low voltage cutoff? It will say lipo or lva somewhere on the esc. If so, the summit low voltage cutoff is probably set higher, stopping the fun sooner when the lower battery dipped lower. Its not a bad thing, baby your lipos and they will reward you with many more charges.

    If it does not have the lvc, the lights will start to dim before power dies fully.

  5. #5
    RC Turnbuckle Jr. Cameron's Avatar
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    Good to know I'm not the only one who has a summit that will kill 1 battery faster than the other.

    But that 1 at 6.5 is getting pretty darn low.
    (RAH) (AH) + [ROMA (1+MA)] + (GA) + (OOH)(LA)

  6. #6
    RC Turnbuckle Jr. pavmentsurfer's Avatar
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    I think the EVX2s built in LVA is set at around 3.4 volts per cell or 6.8 volts per pack. Many LVA's come set at 3.0 volts per cell... some with the digital readout are adjustable. Some with no readout are NOT adjustable and are pre-set to 3.0... which means your EVX2 LVA will kick in before your alarms do.

    What your describing is the LVA on your ESC kicking in. Its a 2 stage system. First it limits the throttle to %50 to let you know the batteries are done, but it still allows you to get the truck back to you. Then after a few minutes it goes into level 2 which shuts the power down completely.

    Just charge your packs back up and go destroy some more Tmaxx's.

    Also, the reason one battery is lower than the other is because one side powers the BEC. Basically, one pack pwoers the radio and servos, the other doesnt. So the BEC side will always be lower than the non BEC side. If your using an alarm you need to make sure its always on the BEC side. Usually the one with the little red tag hanging off the wires.
    Last edited by pavmentsurfer; 12-18-2012 at 08:26 PM.
    Pede, Summit,
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  7. #7
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    Quote Originally Posted by cris View Post
    sounds like the batterys are done and need to be recharged.
    Oh ok, even though the voltage was still good?

    Sent from my DROID RAZR using Tapatalk 2

  8. #8
    RC Turnbuckle Jr. pavmentsurfer's Avatar
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    Technically the pack was dead. Lipos have a resting voltage and once you stop running them the voltage will always rebound back up a few tenths of a MAH. So if your packs are sitting at 3.3 or 3.4 volts per cell they probably ended at 3.1 or 3.2 volts per cell when you stopped running. Which really is lower than it should be.
    Pede, Summit,
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  9. #9
    RC Turnbuckle Jr. Cameron's Avatar
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    Quote Originally Posted by pavmentsurfer View Post
    I think the EVX2s built in LVA is set at around 3.4 volts per cell or 6.8 volts per pack. Many LVA's come set at 3.0 volts per cell... some with the digital readout are adjustable. Some with no readout are NOT adjustable and are pre-set to 3.0... which means your EVX2 LVA will kick in before your alarms do.

    What your describing is the LVA on your ESC kicking in. Its a 2 stage system. First it limits the throttle to %50 to let you know the batteries are done, but it still allows you to get the truck back to you. Then after a few minutes it goes into level 2 which shuts the power down completely.

    Just charge your packs back up and go destroy some more Tmaxx's.

    Also, the reason one battery is lower than the other is because one side powers the BEC. Basically, one pack pwoers the radio and servos, the other doesnt. So the BEC side will always be lower than the non BEC side. If your using an alarm you need to make sure its always on the BEC side. Usually the one with the little red tag hanging off the wires.
    Does the EvX2 LVA monitor each individual lipo for low voltage or does it average? between all 4 cells? There is always a big difference between my lipos when i take them out, im kinda worried that it is going to dump one battery too far till it kicks in.
    (RAH) (AH) + [ROMA (1+MA)] + (GA) + (OOH)(LA)

  10. #10
    RC Turnbuckle Jr. jamann's Avatar
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    Quote Originally Posted by his grace View Post
    Oh ok, even though the voltage was still good?

    Sent from my DROID RAZR using Tapatalk 2
    Yes the voltage comes back up when not under load.are these the batts that were over charged on Nimh mode?
    If so that would explain the cells being out of balance,they may be slightly damaged.keep a close eye on that pack if it is


    Sent using lipo power
    Mountains cant stop me
    they have tried

  11. #11
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    Quote Originally Posted by jamann View Post
    Yes the voltage comes back up when not under load.are these the batts that were over charged on Nimh mode?
    If so that would explain the cells being out of balance,they may be slightly damaged.keep a close eye on that pack if it is


    Sent using lipo power
    Yes these are those batteries lol. This beast still runs like a scalded ape with them.

    I have also come to this conclusion, does one battery run the lights and steering and all other servos? And one battery run the motor? Because the bec motor is always higher charged compared to the non bec.

    Sent from my DROID RAZR using Tapatalk 2

  12. #12
    RC Turnbuckle Jr. Cameron's Avatar
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    ^ yep see Pav's post above. #6
    (RAH) (AH) + [ROMA (1+MA)] + (GA) + (OOH)(LA)

  13. #13
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    Quote Originally Posted by Cameron View Post
    Does the EvX2 LVA monitor each individual lipo for low voltage or does it average? between all 4 cells? There is always a big difference between my lipos when i take them out, im kinda worried that it is going to dump one battery too far till it kicks in.

    Good question
    Sent from my DROID RAZR using Tapatalk 2

  14. #14
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    Quote Originally Posted by pavmentsurfer View Post
    Technically the pack was dead. Lipos have a resting voltage and once you stop running them the voltage will always rebound back up a few tenths of a MAH. So if your packs are sitting at 3.3 or 3.4 volts per cell they probably ended at 3.1 or 3.2 volts per cell when you stopped running. Which really is lower than it should be.
    Pav you always come through, thank you and i owe you an adult drink.

    Sent from my DROID RAZR using Tapatalk 2

  15. #15
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    If you haven't done so already I recommend keeping a battery log and note down how many charges it's taken. Mark your batts and alternate the usages on either sides. Record any abnormalities (btw Onyx 245 can give erratic readings, jiggle the cables if needed).

    It's an extra step but batteries ain't cheap and it's good to know it's history.

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