AEG battery draining too fast? Bad battery, or is it something else?

[Mynock]

Hey guys. Question:

I have a G&P 9.6V 2200 mAh Ni-Mh crane stock battery, which I charge with a BOL basic charger (usually on a 1.5-2.0 AMP setting). I use this with my G&G M4, which has a reinforced AIM gearbox (downgraded to M125 spring from an M130 that originally came inside it) and a stock G&G motor. No fuse in the wiring.

Today I charged the battery up from practically zero after a few months of idle storage; I know it was dead, because the motor would not even think of turning over.

Anyway, I noticed that it took less than 10 minutes until the trickle charge light came on, signaling that the battery was charged, and thought this odd, because I don't recall it ever taking such a short time to charge before.

Nonetheless, I connected the battery to the gun ... only to have it die on me in mere seconds of burst dry-firing. And I mean seconds. Probably not even 300 rounds. It maintained high ROF for the first 130-300 rounds (when in full auto intervals, with a few alternating periods of semi-fire), then started to slow down, and finally choked.

When I unplugged the battery from the gun, I noticed that only about 3 out of the 8 cells were warm, while the others remained room temperature.

I am not a gamer, so I can't really say that I've experienced this battery lasting for "this" long under "such and such" conditions during a game, or compare battery/gun combinations etc. All I know is that I am pretty sure that a battery should not die after 300 shots. I am going to charge it up again and test it out one more time.

Ideally, how many shots should I be able to get with this type of setup on full charge in semi-auto? What about if mostly in full-auto?

What are the odds that my battery is toast? Does it maybe need to be cycled/discharged (which, being NiMh I didn't think it would)? Also, given the gearbox setup in this gun, and assuming the battery is good, can there be any non-battery-related causes for the fast drain? Perhaps the charger is faulty? Any ideas/tips would be much appreciated.

[HKGhost]

some of the cells could be dead and not holding a charge anymore. Use a multimeter to see how many volts the battery holds. if it's less than 9.6, then it's dead.

[theguy]

Was the gun firing with its normal rate of fire?

If everything seemed like it normally does then you should still have all 9.6 volts.

Also, if it really was that only 3 cells were still good, that would mean your battery would only be outputting 3.6 volts. I would be amazed if a 3.6 volt battery could pull a M125 spring.


Regardless, I would say your battery is probably cooked, storing them with no change for long periods like that is a bad idea.

[yuhaoyang]

dead battery.
if you have a voltmeter/multimeter to check, do it.
But it's almost certainly a dead battery.

[ThunderCactus]

It's likely the G&P battery has died, it's an unfortunate truth that 1/5 G&P battery packs contain bad cells. My friend had the misfortune of finding 3 in a row lol

[BobbyDangerous]

I had the same issue then I charged it with a bd charger and it works again

[THe_Silencer]

Try cycling the battery a few times and charge it a .5 amps.

[Kos-Mos]

You overdrained the battery.

If you let the voltage drop under 0.9v/cell (7.2v for a 8 cells pack), the cell chemistry start to consume itselft to give some power.

That is an irreversible thing and you toasted your pack. Cycling it might let it hold 1000mAh, but it will never come back. Just buy a new one.

[ThunderCactus]

That's certainly possible. NiMH batteries lose their charge over time.
Like a car battery, if you leave it dead too long, it never holds a charge again

But there are 2 things that can happen if you overdrain a battery, 1; as stated above, and 2; if you charge it right away, it actually reverses polarity

[Mynock]

Thanks guys. I cycled the battery and charged it using a low amp setting. Tried again and the results seemed much better. I was able to get a good 600 shots out of it without a noticeable drop in ROF before i had to stop because the wife came home. A few hours later I squeezed off a few hundred shots more on the same charge before the ROF started to drop.

Once again, thanks for everyone's help!