How many times have we heard of some hi voltage from an automotive charger killing any of our electronics, except maybe some cheap led lite that should never have been bought in the 1st place.
I also have a Schumacher charger that goes over 16 volts on most any battery I stick it on. But it has not caused any problem. Why ? Probably because it is an automotive charger made for vehicles whose electronics that can handle some 16+ volts now and then,....maybe forever. If they were to fry electronics, don't you think there would have been a recall on them ? DUH!!
I will add that I have had 2 cheap defective solar controllers pump out 17+ volts for who knows how long before I noticed it. And it hasn't hurt any control boards, or anything else that I know of.
The answer to the OP question (read his lips) is keep doing what you are doing !! Automotive smart chargers mommies didn't raise no dummies !