Charging AGM Batteries
I was looking for info on trying to charge, recharge AGM Batteries. If a convenional automatic charger is set to the deep cycle 2 amp setting, will this over charge the AGM Battery? Constructive comme...
Forum Discussion
I have only done the 458AH bank with the 100amper, but--
The time it takes to get to Vabs depends on the charging rate (charging amps vs bank capacity.) Lower charging rate means you go to a higher SOC before reaching Vabs and tapering starts.
It is all fairly proportional though, so we can estimate that for a 740AH bank using 100amps initial charging and a 14.8ish Vabs.
That would be a 100/740 = 13.5% charging rate, quite low, so expect a long time in bulk and reaching Vabs at a higher sort of SOC. My ugly graph says that would be about at 83% SOC (same as a 30amper on a 220AH bank)
So 50-83 is 33% of 740 = 244AH so at 100amps that would take 2.44 hours. Amps would then taper for however long you want.
It takes about 50 minutes with my four 6s to get to Vabs at about 73% SOC using 100/458= 22% charging rate. About 2.2 hours to do a 50-90.
If you had two of those 100ampers and got 200amps that would be 200/740 = 27% charging rate. Same time as using a 60amper on 220. Ugly graph says about 45 minutes to Vabs at about 70% SOC.
(have a spare thermistor or avoid hot restarts! :) )
That showroom charger has the variable voltage as an option, otherwise it is just a straight three or four stage converter with fixed voltages and charging profile. I think Randy can get them or else he makes them himself in his shop, but you would have to be clear about which options you want--has an on/off switch (silly-just plug or unplug) the voltmeter on top option (handy when twiddling the voltage pot knob), and the external voltage pot knob option. Carrying handle is nice for when using it as a portable charger, but not if installing it as a deck-mount, where it adds height.
The time it takes to get to Vabs depends on the charging rate (charging amps vs bank capacity.) Lower charging rate means you go to a higher SOC before reaching Vabs and tapering starts.
It is all fairly proportional though, so we can estimate that for a 740AH bank using 100amps initial charging and a 14.8ish Vabs.
That would be a 100/740 = 13.5% charging rate, quite low, so expect a long time in bulk and reaching Vabs at a higher sort of SOC. My ugly graph says that would be about at 83% SOC (same as a 30amper on a 220AH bank)
So 50-83 is 33% of 740 = 244AH so at 100amps that would take 2.44 hours. Amps would then taper for however long you want.
It takes about 50 minutes with my four 6s to get to Vabs at about 73% SOC using 100/458= 22% charging rate. About 2.2 hours to do a 50-90.
If you had two of those 100ampers and got 200amps that would be 200/740 = 27% charging rate. Same time as using a 60amper on 220. Ugly graph says about 45 minutes to Vabs at about 70% SOC.
(have a spare thermistor or avoid hot restarts! :) )
That showroom charger has the variable voltage as an option, otherwise it is just a straight three or four stage converter with fixed voltages and charging profile. I think Randy can get them or else he makes them himself in his shop, but you would have to be clear about which options you want--has an on/off switch (silly-just plug or unplug) the voltmeter on top option (handy when twiddling the voltage pot knob), and the external voltage pot knob option. Carrying handle is nice for when using it as a portable charger, but not if installing it as a deck-mount, where it adds height.
