Another work around would be to move the AC power to the Inverter. The AC is 4 amps and would work, I doubt the step inverter would cause an issue on my 15 G?
I like the idea of having an emergency option (maybe install a second receptacle in the fridge's bay) for using the inverter. Though it's likely to add another 20% to the battery load from going through the conversion, and thus make the alternator work harder when driving, it does provide a couple of advantages:
1) You can run the fridge for a short time (in a pinch) off the house batteries while parked without shore power or porpane.
2) You can run the fridge while driving if your DC mode has failed - and avoid propane on the drive. I've occasionally gotten a propane failed on my fridge while driving in very high wind, and I think it's simply due to the flame being blown out or failing to start due to turbulence up through those vent panels. So, even though the propane consumption by the fridge is very low, I dislike using it while driving.
I would still want to apply some sort of fix to the 12v mode or at least remove the fuse to eliminate the heating in case the fridge does try to run in that mode - otherwise the PCB could eventually destroy itself. I think it's a several hundred dollar board.
...I also had a bad therm switch ( mounted on the right top of the heat fins. ) my cooling fan did not work, now works correctly. The heat could have caused an issue?...
The therm switch is designed to take that heat, but it's a pretty simple thing and they do fail.
...I don't like the cover on the PCb. I wish it had a heat sink...
Unless you will never drive in bad weather, dusty/windy conditions or high humidity, I'd leave that cover in place. The actual heat generated by a properly working board is easily dissipated through that enclosure, and though the board is conformal coated to guard against the elements, it's never a good idea to unnecessarily expose sensitive electronics.
It is actually not necessary to remove the fuse. Doubling up all the +12 high current traces going in and out of the relay with 12 gauge wire will solve the issue. The heat generated between points A and B is due to the inadequacy of the single sided trace carrying +12V into the 12 volt relay. That is why it gets hot. It is also why the fuse gets "burned" on that side. Beefing up the traces keeps this heat from occuring and also allows the heat generated by the small voltage drop in the fuse to dissapate.
I agree and disagree. Per my original post, I believe that the problematic portion of the heat is caused by the poor spade connectors that were used to socket the fuse and the resistance of the connection that is made to the fuse by the spades. So the fuse can remain as long
as the spades are replaced with a better quality item. Yes, all things equal, single-sided routing will cause more heating, but that SS trace is also a bit wider than the double sided traces. The 30F rise that I measured is in the CENTER of the U-shaped trace, not below it where the fuse is, and is in no way enough to cause discoloration of the PCB. My fuse was burned on both sides - yes the left side moreso, probably due to an additional 20F on that side. Given relatively heat-free fuse connections (or no fuse at all), I think the board will do fine as designed, though both you and I would have put more copper in that path had we designed the it.