Can you use the load side of a solar charger controller to charge batteries ? i have a steca pr 30-30 charging 5 105amp agm batteries to my off grid caravan in the woods ,in mid Devon. And i have lots of 12 volt re-chargeable things to charge. I if i charge straight from the battery bank i do not know what s.o.c. is. Will it harm charge controller? Do i need to add a diode to stop back feed .