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  1. #1
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    Leaving nimh battery empty?

    Im new to all of this and I searched for the answer but couldn't find it. Maybe its a dumb question. Haha. I want to know if its ok to leave my battery ( 7 cell 8.4 v 3000mah nimh id) drained? I just ran my rustler. Now instead of charging the battery after it cools can I wait to charge it say 24 hours? I know its probably not fully discharged since before I took out the battery I could still use the steering but the truck wouldnt move. It should be fine to leave it like this right? If so how long is safe?

  2. #2
    RC Qualifier Panamon Creel's Avatar
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    Not a problem with leaving a NiMH battery at a low charge rate for extended periods of time.

  3. #3
    RC Turnbuckle Jr.
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    Leaving a Nimh pack empty or near empty for storage is a BIG problem as the cells will self-discharge to a point low enough to cause irreversible damage. Never, ever allow Nimh packs to over-discharge!!!!!!!!!!!!!!!!!!!!!!!!!!

  4. #4
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    Ok cool. How long can I leave a 7 cell nimh 3000mah battery discharged ( the state its in after a full run before I charge ) ?

  5. #5
    Marshal ksb51rl's Avatar
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    OP seems to be asking about charge state. PC seems to be answering about charge rate, and is correct with the proviso that the "low charge rate" may be as low as C/300.

    Quote Originally Posted by Kingdad85 View Post
    Ok cool. How long can I leave a 7 cell nimh 3000mah battery discharged ( the state its in after a full run before I charge ) ?
    Depends how low you discharge it. Best practice is to charge it immediately.
    Alt-248 on the number pad =

  6. #6
    RC Turnbuckle Jr.
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    Yeah, I missed the charge rate comment in PC's post. My bad.

  7. #7
    Marshal ksb51rl's Avatar
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    Quote Originally Posted by Kingdad85 View Post
    I know its probably not fully discharged since before I took out the battery I could still use the steering but the truck wouldnt move. It should be fine to leave it like this right? If so how long is safe?
    Quote Originally Posted by Jakey View Post
    Yeah, I missed the charge rate comment in PC's post. My bad.
    Your advice was right on, but stopped short of telling the OP that if the truck won't move, he's discharged the battery too far.
    Alt-248 on the number pad =

  8. #8
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    Yea ive been discharging too much. So when should I stop the vehicle? When the truck slows down?

  9. #9
    Marshal ksb51rl's Avatar
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    That would be my suggestion.
    Alt-248 on the number pad =

  10. #10
    RC Qualifier Panamon Creel's Avatar
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    Stop when you find that the acceleration gets sluggish to avoid having the battery heat up too much which is detrimental to them.

  11. #11
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    I stop the truck today once it slowed down. Let the battery cool for a couple hours now im charging again. I think I should get a new charger, the ine that came with my truck charges at 4 amps which I heard isnt so great for the battery, plus the battery is super hot after charging. Plus side is it only takes 50 minutes to charge ��

  12. #12
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    I have a pack with low usage on it and I've tried 2 chargers on it with no results. I'm assuming this pack is dead forever.

  13. #13
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    but I have also heard you need to drain the battery and not leave it charged just laying around... or is it ok to leave it laying around charged just DON'T charge it again till you drain it?? Guess the only down side to that is when your ready to use it it may not have much of a charge left but you got to drain it before charging it correct??

  14. #14
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    i have 3 out of my 4 packs gone bad now. one of them being a lipo pack. this does not make me happy as this whole setup is only about 4 months old. im using a 2970 traxxas charger. the LED lights just keep flashing. today one of my cells in my pack got so hot it melted the heat shrink.

  15. #15
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    Changing at 4 amps is bad. I really need to get a new charger. Better yet go lipo and charger

  16. #16
    RC Qualifier Panamon Creel's Avatar
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    Quote Originally Posted by n2mini View Post
    but I have also heard you need to drain the battery and not leave it charged just laying around... or is it ok to leave it laying around charged just DON'T charge it again till you drain it?? Guess the only down side to that is when your ready to use it it may not have much of a charge left but you got to drain it before charging it correct??
    LiPo batteries are the ones that you should not store for extended periods of time at full charge which reduces their useful life and get destroyed if discharged too low or left stored at too low of a charge. NiMH are not so sensitive to the charge level but during longer storage they should be cycled every couple of weeks to avoid internal crystal build up which causes a much higher self discharge rate. A neglected NiMH cell with internal crystal build up that won't hold a charge anymore can often be revived by a low rate deep discharge down to 0.4-0.5V per Cell which dissolves those build up crystals. High heat is something that causes significant decrease of useful life with a NiMH battery.

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