Battery changing polarity?

rud0g · #1 01-30-2003, 12:33 AM

Hey everybody,

I have a nice little Blue Toyota Bb clone with yellow flames, and 2 batteries in the chassis.

I regularly get 30 minute run times.

However yesterday after charging, (I use a 4xAA pack for 2.5minutes to charge) I could only run about five minutes.

I charged again and got the same result, so then I pulled everything apart and started poking around with my meter.

The second battery flipped polarity!

(And YES I do know which ends are normally positive + negatvie)

It will not take a charge any more, even accounting for the flipped polarity, it only reads about .95 volts and 0 milliampsDC.

I have plenty of batteries, but it takes a long time to match batteries for voltage/current/drain/charge characteristics and I don't really feel like doing that again.

Anyone know if the Battery is repairable?

eman1 · #2 01-30-2003, 05:51 AM

nope, its shot.

Namuna · #3 01-30-2003, 08:48 AM

Sounds like that battery went into the negative when discharging (I'm going on theory here, but it makes some sense)...Which could explain that flipped polarity.

You probably could salvage that battery, but you'd have to seperate that flipped battery and then run it through several FULL charge/discharge cycles (WHILE monitoring the voltage to MAKE SURE you're working in the positive again) to MAYBE get it working right again.

You COULD salvage, but is it worth the $3-$5 you paid for that battery?

hogjowlz · #4 01-30-2003, 09:20 AM

thats strange.

eman1 · #5 01-30-2003, 11:25 AM

it happens on batteries like the 7.2volt ones for larger scale(1/10) if they arent matched. While you are running, the weaker cell(s) could reverse polarity while the other cells are still discharging. That is why people use matched packs for the larger scale, maybe that would help in this case also.
I see that you tried matching them, maybe it isnt worth the effort of matching the batteries??