Thread: New Battery Maintenance

It was a thought. The symptoms sound like water a battery that is low on water does.

Originally Posted by Kevin22

They typically do not stay in "prime" condition for very long.

You should never charge a SLA (sealed lead acid) battery of that type at more than 2A, 1A is optimal. Your charger is probably a smart charger, they throw 13.5-13.8V at it to start and once the battery is 75% charged they drop to 13V to finish it, then when it is at "full" they drop down to 12.5V to maintain it or they go into a "top off" mode where they raise the voltage to 14V for 5-10 seconds then lower it to 12.5V for a minute and repeat to get the last bit of charge into it. A fully charged prime condition SLA battery is 12.7V resting (taken 2 hours after you remove from charger).

If your charger is still hooked up when you are testing this battery, yeah it could say 12.5-12.7V because that is what your charger is outputting to maintain the battery.

I test SLA batteries all the time, just did yesterday morning. They will test at 12.6-12.7V fully charged, but once you put a load on it the voltage will drop like any battery. Dropping to 12.3-12.5V while a load is on it is normal, if it drops below 12V and is supposedly "charged" then you have issues. If you hook up your fishfinder and the voltage drops to 12.3V, that can be normal. just unhook it and wait an hour and test again, it should have bounced back to 12.6-12.7V. A "bad" battery will continue to drop voltage to 10V or less in a matter of minutes with a decent load on it, you can usually watch the voltage go down 0.01v a second on a multimeter.

A battery fresh off the charger will have what is called a surface charge, could be up to 14.6V depending on your chargers output. Putting a load on it for 10 minutes then letting the battery sit idle for 2 hours will let you see the true charge of it.

Thanks so much! Super informative. My charger is pretty old school- the graphics look 90s or early aughts to me- so who knows what kind of technology it's got going. I'll try to get a pic up. In the mean time, I'll stick with 2A charging.