Batboard

Okay, I'm scratching my head here...

The battery for my ASTRO Saber worked like a charm in the past. It didn't get used much, but held a nice long charge. (It is an aftermarket, no manufacturer listed, but "EB4595" is the model number, 1800 mAh.) Nothing but great performance.

I went to charge it, and couldn't remember which was positive and which was negative, so I pulled out the multimeter. And this is where things got confusing. Across the top terminals of the battery, where they connect to the radio, I'm get 6.73V.

Across the bottom terminals, where the radio should charge, I'm getting 4.60V. No I'm not on drugs, and yes, I checked twice. (Actually, thrice.)

Is this, err, common? Is the battery shot as I'm imagining? Is there harm in trying to charge it? (As in, will it blow up in my face? Should I try charging through the top terminals instead?) The battery's in fine shape, and is even pretty new, which is what has me confused. I could see it being total junk and never working, and I could see it going funky after years and years of daily use, but after maybe 30 charges, suddenly displaying different voltages at different terminals?

I can't speak for the battery charger terminals, but, the saber battery should have 7.5volts nominal voltage... it will be more when fully charged, and less when depleted. your reading isn't bad if it hasn't been charged in a long time.

If you have a maha or other charger, charge it from the top. I don't see that as causing any harm.

Josh wrote:If you have a maha or other charger, charge it from the top.

Precisely what I've got! It just seemed really odd that I'd be getting (very) different voltages depending on where I measured. It didn't seem that there should be any variation, much less several Volts.

There is a blocking diode to prevent battery voltage from being present at the charge terminals, otherwise you could short circuit the battery across those terminals accidently. There is a thermistor to measure battery temp that may be high resistance coupled to the battery + therefore your odd voltage reading on one of the charge terminals.

Chris
N9LLO