I have an small trailer with 200w of solar panels and two 6v deep cycle lead-acid golf cart batteries. The controller I have is Renogy Wanderer 30A, described as capable of separate bulk, absorption and float charges and apparently is programmed to float at a fixed charge at 13.6v after the batteries are fully charged.
The float is not adjustable on this controller. I note that when in float, the amperage going to the batteries at 13.6v is very low, typically less than 1 amp.
My other trailer has a converter which charges at 13.2v float, which I believe is a sign of a good multistage charging system that does not overcharge the batteries.
Is this solar controller overcharging my batteries in float? Or is the low amperage at 13.6v a safe float?
For all standard Lead Acid batteries, the nominal float voltage is 13.5 give or take a few tenths. The original poster has no problems.....its a non issue.
Ed - on the Central Oregon coast 2018 Winnebago Fuse 23A Scion xA toad
Look up the manufacturer's recommended float voltage range for your batteries. Compare that to what you controller is doing. Anything else is nothing but guessing.