3800 mah?

[neweuser]

I have two 8 cell ib3800's. when i cahrge them, they only go up to 2000 even though i set it for 3800 mah. what's the deal? then when i start them over from that point, they take a full charge of 3800?:026:

[MetalMan]

How warm do they get the first time? Your charger might just be false peaking, which charger do you use? As long as they don't get too hot to touch at the end of the charge they should be fine.

[Serum]

Perhaps you have got some imbalance in your pack.

Check to see if any cells of the pack stay cold.

I had the same issues with my 3800's.

[neweuser]

they are staying cool to the touch. the second charge i give them they get a nice warm feeling. i tested all the cells and they are all taking the same charge. i don't get this. i've never had a problem with them like this. My other ones i got from mike are fine. these i got from cheapbattpacks.com. they are brand new! MRC 977 charger.
Serum: what did you do to cure it?

[Sylvester]

Try running your truck till it dies. Let it cool for 10 minutes and try running again - your batteries might not be fully run down.

[phidailo]

I have the same problem as well with the 977 charger. I increased the threshold by 5-10 mv and seems to work fine now. Don't increase too much as it will overcharge

[Mike.L]

what i dont like doing is changing the Mv setting mutch. Me and dom had the same problem with our batteries not charging to full compasity.

Try to fully dis-charge your batteries till your truck slows down dramaticly.

[neweuser]

I have ran my truck to dead. all my truck did was jerk. So, let the batts cool, and put them on the charger, and same thing! I'lltry adjusting my threshhold and keep an eye on them. My other 8cells don't do this though. about to send them back and say to send new ones! thanks guys. will let you know tonight!

[neweuser]

Ok. So i drained the batts totally down. then charged them. still no full charge. One will take 2200, the other about 1910. put them on a second time again, the one that takes 2200 took another 2300 mah. the other won't go past 455 mah now. i discharged them and tried to recharge, same thing. Would this be the charger or batteries? It's like my charger is false peaking or something?

[Sylvester]

Do you have any other batteries to see if the charger is false peaking? It sounds like your batteries, i would send them back from wherever you got them from.

[neweuser]

that is the next step, sending them back. I have another set and will try those again and see what happens.

[BrianG]

Originally Posted by neweuser

that is the next step, sending them back. I have another set and will try those again and see what happens.

Generally, a suitably NiMH battery when charged will start out at ~1.1v on hookup to the charger, increases relatively quickly to about 1.25ish V, then increases slowly to about 1.3v, then increase realtively quickly again to about 1.35 to 1.4v. At the end, the batteries will start to get warm and the voltage will drop a little. Once the voltage drops from the max by the preset value, charging stops. Watch the charge cycle and see if you can watch these stages happen. Or, try to increase your delta V to about 0.04 or 0.05v to help prevent false peaking. If the delat V is too small, any small thing (like slight resistance in the connectors) can cause it to peak.

[neweuser]

Funny that you say that. i took one pack with one of my adaptors, to try to charge one at a time, and it took a full charge. i used the other adaptor on the other battery and it did not take a full charge. Hmmmm, adaptor problem maybe? I gonna discharge all the packs tonight (may take awhile), then try and charge them all with the one adaptor, that may be my problem.
Brian: so what you are saying is that it may not be a bad charger or bad battery, just the v peaking is very sensative? It could be the new packs too though, there are many variables here that i still need to test. Any opinions that have not been mentioned would be appreciated. the bash is coming up quick, i'd hate to have a truck built that can't have power! that would suck!!!!!

[BrianG]

Originally Posted by neweuser

...Brian: so what you are saying is that it may not be a bad charger or bad battery, just the v peaking is very sensative?...

Exactly. If the battery voltage doesn't drop a little at the end of the charge and the charger peaks anyway, it could mean the deltaV is too low, the charger is bad (probably not since you can charge other packs), or something wacky with the battery. You have to watch carefully at the charging voltage though to see the voltage rise to a point and then back down a little. I'd set the deltaV to something like .05v. Just make sure to watch battery temperatures, the higher the allowed deltaV, the more chance you can have of overcharging. Stop when the battery gets warm.

[neweuser]

Thanks BrianG!