Having some trouble with my 75/15 controller and I think I may be best off resetting it to defaults before meddling any more with it. It has worked without issue for a couple of years with a 75W panel connected to a small leisure battery. The battery is also connected/switched to the starter battery via a marine battery relay so that when the motor runs, both batteries are charged. This will also tie the two batteries together for the solar charger to fill. It used to be that the solar panel on a summer day would charge both batteries to 13.7V.
What happened this week is the charge controller shut down the load circuit and I had to reset it by disconnecting/reconnecting the circuits. This happened two days in a row. The jumper was on pins 2 and 3, but I never did anything with it. I left all the other settings alone and it just worked™. I didn't think to verify the battery's charge before I reconnected the controller. That might have been useful to tell if the controller turned off the load based on a low charge.
I have since removed the jumper, removed the largest load (a 12V fridge) and set the load to Always On. But I am still seeing low inflow from the charge controller to the battery, less than 13V, really a trickle compared to what I am used to seeing. By this time of day, the combiner relay would have closed and the two batteries would be getting charged at 13.5+, rather than just one at 12.75V. The panel is showing about 15V and 2+ amps so nowhere near it's potential either.
It seems like I have a low charging problem, now that I lay this all out. But how do I reset the controller to all the defaults so I can remove some of the variables?