Originally Posted by Mheitner
Solar panels for onboard battery winter storage I have four size 74 liquid cell batteries that are connected in series on my Mainship 30 and would like to attach a solar panel and controller to preserve the batteries with a trickle through the long winter storage season. Obviously a novice, I would like to know if I use a single solar panel (what size?) and a single controller (what size). Do I then just clip one cable to the positive post of battery #1 and the second cable to the negative post on battery #4?
#1 Charge to 100% SOC in the late fall / EQ if possible
#2 Physically disconnect all batteries from the vessel
#3 Disconnect each battery from any other batteries
#4 Come back in the spring and reverse the process
We've seen far too many banks ruined by unattended charging including batteries left with solar charging. In cold weather the self discharge rate is almost nil.
Winter Battery Storage & Self Discharge Characteristics