OP wants to do 50-90s. A 60 amper on a 220AH bank does constant 60 and reaches Vabs at about 70% SOC and amps will then taper for the Absorption Stage.
So your gen will slow down then as amps taper and you can't use that as a marker for when to stop the recharge. You have to keep going until you get to 90% SOC.
45Amps on 220AH will do Bulk at 45 and reach Vabs at about 76%SOC and amps then taper with the gen then slowing down.
Even so the 60 amper will do the 50-90 in less time because it was doing 60 instead of 45 for the 50-70 and then its amps taper but from a higher level for the 70-76. They are equal in time for the 76-90 but the 60 holds its shorter time overall.
It must be time to inflict my ugly graph on everyone again! :)
