SLA Battery Charging? Answered
Quick question about charging SLA Batteries, I haven't really dealt with battery charging too much in the past. I have two 12v 5Ah SLA batteries, in series, and I have built an under/over voltage protection circuit for each of them, but while charging I noticed that testing voltages across each battery, they are different, however, as soon as I remove the charger and test them as is, they have the exact same voltage (+/-0.05 volts, they are very close). Is this just because the charger is hooked up, or should I be worried at all about that?
I am charging them to 14.75 volts each, or would like to, they say they should be charged to 14.5 to 15v right on the front of them. While charging they both climb, but one climbs faster and stops once the voltmeter reads 15.2v across it. 0.2v over the rated value really doesn't seem to be of major concern, I just find it odd the different voltmeter readings across the batteries are different while the charger is connected and identical when its not. Does it have something to do with charging them in series? I did read that you really can't measure batteries while charging, you have to disconnect the charger first, but any insight would be appreciated.