How can I protect control boards from over DC voltage

I equalized today and while I didn't use the disconnect switch, I did pull the fuses for the heater and refer and turned off all lighting.

My solar equalizes at 15.5 out of the controller. I see 15.3 at a 12 volt outlet near the distribution panel. The refer is farther away so it would probably be 15.1 or 15.2. I never neasured at this point. The service manual says never exceed voltage for refer is 15.4 and I recently had a control board failure. I always use the disconnect when I equalize but I may have forgotten when I equalized in November. I had a Board failure in mid December.

If your thinking of the fridge control board
Yes..you could use a DROK buck
Just pay closer attention to the control limits
There are minimum and maximum limit

It seems to be in the 2v range
Meaning you can't make 13v down to 12v or 20v down to 12v
in other words there is minimum voltage drop and a max voltage drop
Depending on which one you get

getting the buck/boost board might be the best bet

put the board in the fridge compartment
With no other loads

I would not try it with the furnace and A/C controls

Just how high are you equalizing? Anything that runs on "12v" should be good at 15v, especially "automotive" stuff like an RV uses. 12v nominal is more like 13.2+ most of the time, 14.4v some of the time, and well, like you equalizing, a bit higher too

I wouldn't go putting buck regulators on all your dc loads, despite what ebay / amazon claims, a buck regulator is seldom a one size fits all power supply. they generally need to be matched to the load. DROK's el-cheapo multi-turn trim pots does not count as matching the smps to the load.

If you're truly concerned about your converter failing, replace it with a quality unit, one that has integrated over-voltage protection.

just my 5 cents as an armchair electrical engineer

I would experiment with one somehow... The BUCK BOOST type regulators are known to emit alot of RFI SIGNALS in the VHF/UHF radio/TV signals... The low wattage ones used with some of the power regulators for some of my LED LIGHTING has caused me alot of problems with my HDTV, WX RADIO, Ham Radios, etc...

The higher DC CURRENT BUCK BOOST circuits may be an even bigger RFI SIGNAL problem...

This is my experience using the BUCK BOOST circuits at any rate... Using high current INVERTERs also gives me similar RFI problems with their built-in buck boost circuits.

Roy Ken