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  1. #1
    RC Enthusiast
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    fairly new 8 cell, but I think it's trashed.

    Hi everyone, this is my first post, and I'm just trying to figure out why my 4 week old battery is already trashed (or at least I think it is).

    We run a Rustler VXL, and last month I ordered an 8 cell, 9.6V 5000mah battery. I've been charging it with a Duratrax fast charger which attaches to a car battery, and then charges the 8 cell. The charger is rated at 4.0 amps.

    I think I've read that using a fast charger on your RC car battery will kill it faster than using a slow charger, but I thought the 4 amp charger with the 5000 mah battery would be just fine. At least that's how the instructions that came with the charger made it sound.

    Everything was great for about 50 charges and runs over the last 4 weeks, but now the battery is clearly very weak compared to how it was when it was new.

    Have I been abusing my battery by using the fast charger, even though it's 5000mah? Does it even matter what the mah number is when using a fast vs. a slow charger?

    Any other words of wisdom, other than "go lipo"? (I'm probably going to do that anyway).

    Thanks.
    Last edited by staledog; 05-04-2013 at 05:49 PM.

  2. #2
    RC Turnbuckle Jr. Jimmie Neutron's Avatar
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    How have you been storing it?
    What were the temps of the battery after charging?
    What were the temps of the battery after running?
    Does your charger have the capability to cycle the battery?
    Do you run your RC until it stops moving?
    Do you run your RC until it slows?
    Is the charger a timed charger or a peak sensing charger?
    Whatever it is I just said... I could be wrong.

  3. #3
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    Quote Originally Posted by Jimmie Neutron View Post
    How have you been storing it?
    What were the temps of the battery after charging?
    What were the temps of the battery after running?
    Does your charger have the capability to cycle the battery?
    Do you run your RC until it stops moving?
    Do you run your RC until it slows?
    Is the charger a timed charger or a peak sensing charger?
    I have not done anything "special" to store it. I just usually put a full charge on it after it cools down following a run, and then sometimes "top it off" with another charge before we use the car again a few days later.

    Specific temps I don't know, but when it was new, the battery would be very warm after a charge, now it barely gets warm.

    After a run, same thing. Actually it would get fairly hot after a run when it was new, not now.

    The charger does not cycle the battery, it just charges it as described below.

    The charger is a peak charger, there is a solid red light on the charger while it is charging, and then a flashing red light when the charge is complete.

    We usually run the car until it is going pretty slow and then quit, but not until the car is at a dead stop.


    I knew lipos were more complicated, I did not realize there was this much involved with nimh batteries too.

  4. #4
    RC Turnbuckle Jr. Jimmie Neutron's Avatar
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    Cycling might help... but the pack may be worn out too. Not all chargers are created equal, so to speak. Some treat the cells very well while charging, some do not... I am not sure of that particular charger's habits.
    Whatever it is I just said... I could be wrong.

  5. #5
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    Quote Originally Posted by Jimmie Neutron View Post
    Cycling might help... but the pack may be worn out too. Not all chargers are created equal, so to speak. Some treat the cells very well while charging, some do not... I am not sure of that particular charger's habits.
    Thanks, I've had that charger a few years but I seem to remember it not costing too much...I know you pretty much get what you pay for. The battery is only about 4 weeks old, so maybe the charger is the problem. This sounds like a good opportunity to just make the jump to lipo.

  6. #6
    RC Competitor
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    Exclamation should fix

    once and a while charge at 1.5. (no matter the mha i charge at 3.0) i use a duratrax charger that great and does lipo. link:http://www.amainhobbies.com/product_...-5A-3S-40W-x-2

  7. #7
    RC Champion
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    Those chargers are not really ment for the higher mah batteries. At best you are only getting 1/2 charge. Had a similar charger and after it said it was charged I hooked it to my hitech charger and was able to put another 3000 mah in a 5000 battery

  8. #8
    RC Champion
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    Quote Originally Posted by gilrc10 View Post
    once and a while charge at 1.5. (no matter the mha i charge at 3.0) i use a duratrax charger that great and does lipo. link:http://www.amainhobbies.com/product_...-5A-3S-40W-x-2
    I've this charger and it doesn't hv storage mod on it ,
    1 Rusty VXL

  9. #9
    RC Turnbuckle Jr. Jimmie Neutron's Avatar
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    Correct.
    And I consider storage to be a required feature for a charger.
    Whatever it is I just said... I could be wrong.

  10. #10
    RC Racer
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    Put it on the slow charger for a day it will be brand new.

  11. #11
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    hmmm... mines the same but i only got ONE good run out of it

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