Regulater for a solar battery charger?

You have asked a tough question.

Battery charging is done by constant current, by constant voltage, by temperature, and by pulses. Any of these are appropriate, under certain conditions.

Some batteries respond well to constant voltage ... they reach their float voltage and the current drops off accordingly.

Some respond well to constant current with a time cut-off or a voltage/temperature sensor to trigger the cut-off point.

Some chargers measure the battery temperature and use an algorithm to end charge and then enter into trickle charge.

Some chargers use delta V/I to measure the dynamic resistance and act accordingly.

Some chargers use V/delta I to measure the dynamic resistance and act accordingly.

Not trying to blow you away, but this is not a simple subject.

would it be simpler if he indicated what type of battery he plans to use?

would it be simpler if he indicated what type of battery he plans to use? I hope so. I've been told the batteries they use on golf carts are best for storage with a solar system. I had thought those deep cycle marine batteries but people on the RV group said the golf cart batteries are better

I think you want the most amp-hours/dollar, and golf cart batteries have lots of AH and not too many $$. I used to drive the Boy Scout bus and those bus batteries are big ol boogers, Get a couple of those dudes and you'll be all set.