Originally Posted by CMS
Solar is never going to hurt anything and can only help. What will help more is if you can pause loads long enough to allow your solar to charge the bank to 100% SOC, and do so more than once per week. Partial state of charge cycles for more than a week really cut into cycle life.
The more frequently you can get back to 100% SOC the better off you are. If you can't get to absorption voltage daily, and hold it there, you really only have a few choices;
#1 Buy batteries more often
#2 Reduce your loads/consumption and be more efficient
#3 Increase the size of the PV array
#4 Extend your morning engine run/dino fuels charging duration
If you ever want to get back to 100%, even if it is just every third day, your sun up PV energy output needs to exceed day time loads, plus used loads overnight by the amount you need to restore + charge inefficiency....
CMS: Thanks for that. That is pretty much what I am doing already. We seldom go below 80% SOC overnight, and usually just to 90% SOC. On a sunny day we can get to 100% by late afternoon. But the voltage doesn't get much above 13.5 and often less than that.