Minor solar controller may help
I have been watching our Blue Sky Solar Pro Remote to see ho it behaves in various conditions, on and off shore power.
Off of shore power it behaves as always, with the only known glitch being that it rebulks if the voltage drops below float voltage. This happens too often in cloudy conditions, and can have the controller in absorption on full batteries when it should be in float. Newer models are supposed to move the rebulk down to 12.8v, which will be much better.
When on shore power, with the shore charger in float on full batteries, you would expect the solar to also be in float, except for maybe a charge cycle first thing, which would go to float very quickly. What appears to be going on is that minor variations in voltage caused by things going on and off (like the frig), trigger the solar to go into rebulk, back out awhile later, etc over and over. It can actually hang at voltage between float and absorption under weaker sun, which is undesirable.
The cure appears to be, on our setup, just reducing the solar float voltage to .1 volt below the shore charger float setting. Once done, the solar just sat in float like it should.
It is also desirable to have the same temp compensation slope for both, so the maintain that .1v difference over temp changes.
I can't say if other brands beyond Blue Sky do the same, but they may. I think it may make sense for the shore settings to all be .1 volt higher than the solar, so the shore charger has the full control when in use.
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