acceptance charging rate AGM batteries
Hi all, It is generally thought that acceptance rate for a flooded deep cycle battery is about 12.5 amps per 100 amp-hours of capacity once the bank is at 85% state of charge. I know that accept...
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I think the question is complex, so my answer was incomplete.
The 12.5a at 85% per 100AH marker needs to have a voltage specified, but of course that battery voltage would still be rising on the way to a higher charger voltage (Vabs) going through 85%.
I use this type of marker to judge when to shut off the generator at about 90% SOC doing 50-90s. My rule of thumb is 5 amps per battery, so I watch the Trimetric amps (or Vector charger amps read out) and for four batts that is 20amps. That was for 14.4ish and I now charge at 14.8, so in fact I could stop sooner at some higher amps now.
So the question is, for an AGM, what is the marker for doing that same thing? You need to specify the charger Vabs, and then ask what would the amps be at 85% for a 100AH AGM, assuming the charging amps is higher than what the marker amps would be.
Eg, in that 12.5a per 100AH case, a 10 amp charger would go past 85% before amps tapered, so you would only see that at 85 if you used say a 15 amp charger or higher.
I don't know if that would be higher or lower amps than 12.5 for an AGM. It might relate to the higher resting voltages per SOC of an AGM.
With no AH counter, which would make it a lot easier, you could run a few trials and note the resting voltage after different marker amp amounts. This would give you a rule of thumb amps amount to stop the generator recharge at near your desired SOC. (50-80, 50-90, etc)
The 12.5a at 85% per 100AH marker needs to have a voltage specified, but of course that battery voltage would still be rising on the way to a higher charger voltage (Vabs) going through 85%.
I use this type of marker to judge when to shut off the generator at about 90% SOC doing 50-90s. My rule of thumb is 5 amps per battery, so I watch the Trimetric amps (or Vector charger amps read out) and for four batts that is 20amps. That was for 14.4ish and I now charge at 14.8, so in fact I could stop sooner at some higher amps now.
So the question is, for an AGM, what is the marker for doing that same thing? You need to specify the charger Vabs, and then ask what would the amps be at 85% for a 100AH AGM, assuming the charging amps is higher than what the marker amps would be.
Eg, in that 12.5a per 100AH case, a 10 amp charger would go past 85% before amps tapered, so you would only see that at 85 if you used say a 15 amp charger or higher.
I don't know if that would be higher or lower amps than 12.5 for an AGM. It might relate to the higher resting voltages per SOC of an AGM.
With no AH counter, which would make it a lot easier, you could run a few trials and note the resting voltage after different marker amp amounts. This would give you a rule of thumb amps amount to stop the generator recharge at near your desired SOC. (50-80, 50-90, etc)
