AGM charger amps

[SC Maintenance]

If its under 13.7V its not charging. The over voltage has to be at least 1V higher than the battery voltage to get current to flow into the battery at all - which if the battery is almost charged, would be in the 13.6 - 13.7V range - that's to get any current to flow at all.

 

[SubLGT]

I just connected a new “Viking” charger with a digital display. It slowly climbs. Then quickly falls. Does it again. Now it’s just been hanging out at 13.5....

It should climb to 14.4V during the initial bulk phase of charging, then stay around 14.4V during the absorption phase for 0.5 to 4 hours, then rapidly drop to the float voltage of 13.2-13.4V

BU-403: Charging Lead Acid

BU meta description needed...

batteryuniversity.com

 

[SHOZ]

AGM chargers are a rip off. My 2/6A 40 year old charger does just fine with them. My company developed the AGM battery and we originally used the old resistance stuff and light bulbs back in the 70s for charging the industrial sized ones.

Final battery voltage is dependent on the gravity of the electrolyte. High SP gravity will give you a higher voltage. AGMs typically are in the 1.300 SP range while a normal lead acid is 1.250-1.275 SP when fully charged.

 

[LeakySeals]

It should climb to 14.4V during the initial bulk phase of charging, then stay around 14.4V during the absorption phase for 0.5 to 4 hours, then rapidly drop to the float voltage of 13.2-13.4V

BU-403: Charging Lead Acid

BU meta description needed...

batteryuniversity.com

That’s what it was doing. After less than an hour the red back light went out which means it’s in maintenance mode. I guess it was figuring out if the battery need to charge, determined that it didn’t and stopped.

 

[jeffy876]

You can easily charge too fast, you can't easily charge too slow. Not unless you're charging at like 12mA. Anything over 0.1A will charge it just as well as anything else, it'll just take longer.

Now it’s just been hanging out at 13.5. Is that what I couldn’t see with my idiot chargers?

That's it going to float voltage and topping off the last 5-10% of the battery. That's good, you want it to be there for several hours.