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  1. #1
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    Unhappy 7 cell nimh now 6 cell :( are 4000 lipos ok ?

    Never had luck with nimh but we wont go with my electristar story with Nimh.

    well they strike again, with the Summit.

    I noticed i was running slower in 2nd. so after doing a watt meter check . one battery was only putting out 4amps the other was something like 28 amps and 220watts . so then i called tech , they said its either the batt or the ESC . so then i tried swapping batt connections. same thing. so that ruled out the ESC. at least now i know what this thing pulls on each lead (well if battery's are working .

    Tried to cycle the bad battery. even tried auto charge . same lower peak voltage . should be peaking around 10.7 but this one only gets around 9.8 . thinking its dead already. I took the skin off and tested each cell. all around 1.4 (just off charger ). but the one cell at the end was 0.01volts. Crap.

    i soldered on leads to that one. and have tried to revive . but its dead. even tried Reflex method with one of my chargers .

    LIPO time. Nimh sucks .

    How are two 4000 mah 2s on summit ?

    also does anyone know how to connect a single 4s ?

    I have one for my jet that fits in the stock housing of the summit its only 2650 but its a 40 c .

    not worth shipping batt back to traxxas (still under 30 day) , besides i did surgery so ill bet they wont except. no biggy. i now have a 6 cell 3000 pack LOL.

    Thanks

    it does not pay to be nice to nimh battery's never saw more then 130F , and never charged over 3amps . they just suck

  2. #2
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    with stock batteries the run time was annoying, charge it up for an hour and get 15 minutes... so I got myself some 9000mah lipo's and I haven't been able to drain them out completely yet because my hands turn to ice so fast, I recomened getting somthing with a real high mah rating becauase the more run time the better
    anything can be fixed with duct tape and zip ties

  3. #3
    RC Turnbuckle Jr.
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    Quote Originally Posted by VonGearStripper View Post
    Never had luck with nimh but we wont go with my electristar story with Nimh.

    well they strike again, with the Summit.

    I noticed i was running slower in 2nd. so after doing a watt meter check . one battery was only putting out 4amps the other was something like 28 amps and 220watts . so then i called tech , they said its either the batt or the ESC . so then i tried swapping batt connections. same thing. so that ruled out the ESC. at least now i know what this thing pulls on each lead (well if battery's are working .

    Tried to cycle the bad battery. even tried auto charge . same lower peak voltage . should be peaking around 10.7 but this one only gets around 9.8 . thinking its dead already. I took the skin off and tested each cell. all around 1.4 (just off charger ). but the one cell at the end was 0.01volts. Crap.

    i soldered on leads to that one. and have tried to revive . but its dead. even tried Reflex method with one of my chargers .

    LIPO time. Nimh sucks .

    How are two 4000 mah 2s on summit ?

    also does anyone know how to connect a single 4s ?

    I have one for my jet that fits in the stock housing of the summit its only 2650 but its a 40 c .

    not worth shipping batt back to traxxas (still under 30 day) , besides i did surgery so ill bet they wont except. no biggy. i now have a 6 cell 3000 pack LOL.

    Thanks

    it does not pay to be nice to nimh battery's never saw more then 130F , and never charged over 3amps . they just suck
    How many cycles did you have on the Nimh packs before you noticed the drop in peformance?

  4. #4
    Marshal Dadx2mj's Avatar
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    I also wonder how many cycles were on the packs and how far you discharged them on those cycles. Did you run the truck until it would not move or did you stop has soon as you saw it starting to slow down?
    BlindMan Racing
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  5. #5
    RC Turnbuckle Jr.
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    also does anyone know how to connect a single 4s ?
    I do



    Given the choice 2x 2s would be better really, saves rewiring the esc, but if you already have a 4s pack ( minimum of 20c 4000mah, even thats pushing it a bit ) then its simple enough to just follow that diagram and stick a jumper on the unused plug and wire up a 4s LVC device ( or use one that plugs into the lipo's balance plug- buzzer type lvc alarm ).

    Edit: dont bother using your little 4s pack, its way too small for use in a 13lb MT. Go buy a pair of 4500-5000mah 25-30c 2s lipos for best results.

    Last edited by ArmyofDarkness; 12-21-2010 at 11:26 AM.
    Keeping the Mods busy is my specialty...

  6. #6
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    Cycles I would guess is about 25 times now . thats in 17 days . as far as running them down. it always had more then enough power to still run in either gear . I would see lights dim to much at around 3/4 or 5/8 throttle. I mostly played with it at night so I needed the lights to see were i was going. when only crawling around in first it was harder tell. but i would shift to 2nd once and awhile and give it punch , to see were power was.

    I think i started noticing power lag about 3 days ago , then again maybe i was getting use to its speed in 2nd gear. but a day ago what caught my attention was the fact one battry would not peak as high as other . and then what got me bummed out was when i tested the truck with watt meter . and what made me sick was when traxxas suggested to send back the batterys and the ESC. NO way man! i want to run my summit LOL. so had to find exactly what was wrong.

    the other battery is fine, and after pulling the one bad cell last night and going to 6 cell . that pack is alive again.
    in fact just about to test watts today , to really see how that pack is working.

    i think for fun ill send Traxxas the one bad cell . since its useless for me. Maybe it will help them , who knows.

    the chargers used on these battery's are a Hyperion 1210i , Triton 2 , and a ICE (all i use Temp probs, since i mostly use lipos on my aircraft). I used the ICE to do that Reflex charge to wake up dead cell. but no go with this one, that cell has no response.


    meanwhile i ordered 2 Car 2s lipos 4000 mah 30c, all the bigger car ones were out of stock.
    by car i mean Hard case type. also 40c puppys out as well. oh well these should get me going again, until i can grab monsters later.

    Thanks for Input and Help. now i gotta see how my 13 cell monster works with the watt meter now. ill keep yah posted. and post the full info. Ok Burn out time

  7. #7
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    UPDATE: Topped Battery's for testing . good battery 10.80 volts 7 cell hottest cell 80F (was charged last night , this only a top off)

    bad battery 6 cell (bad cell removed) 9.2 volt hottest cell 68F

    ok now the watt runs , this is down on smooth concrete , slippery clutch is about 3/4 turn , all stock , with stock tires.
    2nd gear slammed full throttle . 3 times to warm up battery's a little .

    on 4th run these are the readings .
    good battery hooked to BEC side 201.5 watts 25.16 amps 8.01 volts peak 7 cell 85F Temp after runs hottest cell.
    bad battery hooked to non bec side 35.6 watts 5.16 amps 6.94 volts peak 6 cell 74F Temp after runs hottest cell.

    I can see temperature has allot to do with numbers . yesterday i was getting 220 watts but battery was much warmer at 100F
    at any rate even after removing one cell , i am still getting low numbers from that one pack. . OH well gotta wait for the lipos to come in.

    unless there is away i can run that 4s pack i have. but it dawned on me i would probably have to run a external BEC and un hook the traxxas bec power. since i cant shove 4s into the Traxxas one. Bummer cant play . Heli time again

    Hope info helps someone with battery troubles.

  8. #8
    RC Turnbuckle Jr.
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    There is a very good chance the pack was over-discharged. This is very easy to do and once done it permanently damages one or more cells in the pack. Just like with LiPo, Nimh should not be over-discharged. As soon as you notice the truck slowing, STOP. Allow the packs to completely cool down, then charge and run again.

  9. #9
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    Thanks Army of Darkness for info on 4s and recommend lipo capacity.
    i gather some how that LVC circuit is allowing the BEC side of Traxxas esc to not get to many volts.
    I would think one needs a BEC that can take the 4s voltage. anyway . great info. should have dawned on me to just bridge the other battery lead. LOL just like converting a electristar .

    Gee I hope the the 2 2s 4000mah 30c's will be enough .

  10. #10
    RC Turnbuckle Jr.
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    For good reasons Army of Darkness can sometimes be conservative on the LiPo requirements he posts and I am not going to question that overall, however I will say any good, accurately rated, 5000mAh/20C LiPo packs will be more than adequate for a stock Summit. I have operated my Summit on two, 2800mAh/20C/2S packs with absolutely no problems at all. In fact the little 2800mah packs were barely warm after running them hard until the power dropped. That being said, 4000mah/30C packs will do just fine.

  11. #11
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    Thanks Jakey. Now I dont feel like i wasted some money . Wooo

    Much appreciated.

  12. #12
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    You CAN NOT run an EVX2 on a single 4S lipo. The motor circuit runs on 4S .... but the BEC circuit requires 2S input or it will be overloaded. It can be done if you add an external BEC that can operate on 4S input.

    I make tap adapters and power harnesses.

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