Thread: Duracell AGM

The battery is probably charged based on the voltage you are seeing, so likely either your charger indication is wrong or it has a time interval it waits before calling the battery charged.

There's no way for the charger to know what the state of charge of the battery is until it is nearly completely charged. The 13.1V the charger is providing now is safe long-term for the battery, so I'd leave it on at least another 24 hours, then unplug the charger and measure battery voltage after it sits all day or overnight. Full charge voltage for that battery is 12.80V.

Originally Posted by CatFan

The battery is probably charged based on the voltage you are seeing, so likely either your charger indication is wrong or it has a time interval it waits before calling the battery charged.

There's no way for the charger to know what the state of charge of the battery is until it is nearly completely charged. The 13.1V the charger is providing now is safe long-term for the battery, so I'd leave it on at least another 24 hours, then unplug the charger and measure battery voltage after it sits all day or overnight. Full charge voltage for that battery is 12.80V.

I was hoping you would respond CatFan.
The charging percentage indicator was working Saturday morning and yesterday when I plugged up to another charged battery (wet cell/standard), which is why I am puzzled.
I left it charging last night, so I'll unplug tonight and check voltage the following day and see where I'm at.

Got home yesterday and charger was showing 25%, so left it plugged up and changed to 2 amp setting.
Checked this morning and it showed 100% charged. I don't fully understand the AGM technology, but I assume the battery was drained pretty good or I should have left at 2 amps originally?

10A would be the way to go. 2A would take close to a week to fully charge a battery. You 100% can't trust any charge percentage indicator. You can't know unless you know what kind of battery is hooked up. At 12.8V, a Deka is 100% charged, but an Odyssey is only at 97% charge at that voltage and an Optima only about 80%.

Great info, Glad I found this post. I just upgraded both of my boat batteries to these (from Sam's Club). Great warranty. Set them on the trickle charger and tested once done and 12.8v. Good to head to the lake

I run 2 - 29's and after 6/8hrs of fishing, they charge overnight at 6 amps. I use a onboard charger. The more you use them, the quicker they will charge, it seems.

I have a schumer Charger, sounds like the one you are describing. I notices it will get stuck at a certain voltage, say 65 percent, then I will need to go out and cycle the voltage charge button and it seems to cause it to start charging above 65 percent or whatever it was stuck on, not sure why, but I read on-line other folks having the same issue with the Schumer Charger.

I think the charging issue I was having was because the charger was cutting in and out. Thats why it was taking longer than it should. Eventually, the charger stopped working completely. No fan noise or anything. It was @5-6 years old, so I bought another one. No more issues.