Charging GC2 with Rogue MPPT Solar
Charging a pair of USB2000 golf carts with the Rogue MPPT 3048. US battery says the absorb voltage should be 14.7V (for 2 GC2 in series) held for 2-3 hrs, with charge terminated by max time or when...
Forum Discussion
It should be noted that the OP has only a pair of 6s. This means his charging rate is higher (charging amps/battery capacity) so he will reach Vabs at a lower SOC than if he had a bigger battery bank.
This has implications for how to get the rest of the SOC done. Also for any given daily AH usage, his morning will start at a lower SOC and he will be doing deeper cycles than if he had four 6s. IMO there is a difference between deep and shallow cycles for how much voltage it takes to put the sulfate back into solution to get to 100% SOC.
IMO this makes it more likely he will need to keep that voltage high all day. In my case, the shallow cycles and lower charging rate makes the SOC by the time the batts do get to 14.8 quite high so there isn't much left to do to get to 100%. This is likely why I can get there at 14.4 given time to do it.
This last observation is supported by noting I can still get there when now I have recently gone back to a six-battery bank. The charging rate is even lower on the bigger bank, the cycles are more shallow, and the SOC by the time it gets to 14.8 is higher.
BTW, another "tell" besides the SG baseline indicating the batts are close to 100% is how the Trimetric AH counter goes over zero to positive numbers. With my set-up it goes together that unless the AH counter is in positive territory 8-12 AH "over" the SG will not be to baseline. I speculate you could use that indicator with AGMs since there is no SG.
(I reset the AH counter back to zero from "over" at dusk when that happens)
This has implications for how to get the rest of the SOC done. Also for any given daily AH usage, his morning will start at a lower SOC and he will be doing deeper cycles than if he had four 6s. IMO there is a difference between deep and shallow cycles for how much voltage it takes to put the sulfate back into solution to get to 100% SOC.
IMO this makes it more likely he will need to keep that voltage high all day. In my case, the shallow cycles and lower charging rate makes the SOC by the time the batts do get to 14.8 quite high so there isn't much left to do to get to 100%. This is likely why I can get there at 14.4 given time to do it.
This last observation is supported by noting I can still get there when now I have recently gone back to a six-battery bank. The charging rate is even lower on the bigger bank, the cycles are more shallow, and the SOC by the time it gets to 14.8 is higher.
BTW, another "tell" besides the SG baseline indicating the batts are close to 100% is how the Trimetric AH counter goes over zero to positive numbers. With my set-up it goes together that unless the AH counter is in positive territory 8-12 AH "over" the SG will not be to baseline. I speculate you could use that indicator with AGMs since there is no SG.
(I reset the AH counter back to zero from "over" at dusk when that happens)
