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  1. #1
    RC poster
    Join Date
    Mar 2010
    Posts
    4

    LiPo Battery HELP!

    I keep killing my LiPo batteries (they just stop working).

    I have the E-Maxx Brushless truck and i am running this battery from *********.

    Spec.
    Capacity: 5000mAh
    Voltage: 2S1P / 2 Cell / 7.4v
    Discharge: 20C Constant / 30C Burst
    Weight: 272g (including wire, plug & case)
    Dimensions: 135x45x22mm
    Balance Plug: JST-XH
    Discharge plug: 4mm Bullet-connector

    I have the Onyx 230 charger and a balancer that i hook the battery up to charge. After a full charge and the balance says the battery is balanced i hook up my batteries to my truck. Start it up and run with it. I have killed 4 batteries out of 6 so far. I got 10 feet with 1 battery and my truck stopped dead in its tracks. I later realized that just 1 of the batteries were dead. I could not get a reading from the plug or the charge plug on the battery. I just figured this to be a bad battery. I had another set that i had used a couple of times and it did the same thing .... Now i am starting to get the feeling that i am doing something wrong, I just cant figure it out. I took a reading from this battery and it would not give me a volt reading from the plug that goes to the truck but i could get a reading from the balance plug and i could also hook it up to the charger and it would recognize a battery.

    I posted this on the ********* forum and someone said i got the wron batteries, that the constant amps are to low for this MMM.

    Has anyone experienced this before or know what i am doing wrong?

    Please help and thank you!

    Keith,

    Semperfi

  2. #2
    RC Racer
    Join Date
    Dec 2009
    Location
    Germany
    Posts
    205
    your batts are to week, you need at least lipos with a countinous C rate of 30!, at 5000mAh, because your MMM sucks a lot of power: up to 150 A

    5000mAh x 20C = 100A
    5000mAh x 30C = 150 A
    5000mAh x 40C = 200A
    E-Maxx, MMM, 4S - 6S, Akula :-)

  3. #3
    RC Competitor
    Join Date
    Mar 2010
    Posts
    56
    I've been running a 5000mah 20c 2s lipo in my emaxx since I've had it. No problems here.
    WHere's your lvc at? Are you over discharging?

  4. #4
    RC Racer
    Join Date
    Dec 2009
    Location
    Germany
    Posts
    205
    maybe you are a careful driver
    E-Maxx, MMM, 4S - 6S, Akula :-)

  5. #5
    RC Qualifier
    Join Date
    Mar 2008
    Location
    Alberta Canada
    Posts
    820
    Your batteries are NOT TOO WEAK. I run 4000mah 25C batteries and there is no problem. The math makes mine capable of the same output as yours (100 amps), and I'm in my second year running them.
    Do not believe the soothsayers that tell you they are too weak.

    I'd be more inclined to think your problems are a loose connection. Maybe it's the plug on the battery, or internally maybe one of the solder joints have come undone.
    IF your batteries were too weak, you would still get a voltage reading from them, albeit low, you'd get something. If they go from full charge to zero like that, then it's gotta be a fault or connection fault.
    You are unique just like everyone else

  6. #6
    RC Champion
    Join Date
    Aug 2003
    Posts
    2,261
    Given the info listed here there's a connection problem on the main leads.
    4s Pede, 6S Maxx, 3S Rusty, 6S slash

  7. #7
    RC Qualifier
    Join Date
    Feb 2010
    Posts
    261
    Try it with a NIMH battery and play with the wires, you have something loose with the wires, if you short this out it won't cost as much as Lipo's.

    Check all connections, to the Motor to the ESC to the battery leads etc....

  8. #8
    RC poster
    Join Date
    Mar 2010
    Posts
    4
    Here is a picture of where the connection was being interupted (the red arrows). My buddy added the white wire to act as a bridge between where the solder was (melting away?).
    Last edited by Semperfi1974; 04-25-2010 at 01:19 PM.

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