This is why I posted as much information as I did regarding my failure.

Good analogy Jim, however, I still question exactly what did happen(?)

Was it the charger that messed-up the rest of the system -or- the freaking-out, failing battery?

The water heater board fried only minutes after I goosed the brakes. This was BEFORE I got home and plugged-in to shore power, thus, it seems prudent to assume that the battery caused a DC spike to the Water Heater and not the converter / charger.

As soon as I exited off the highway to finish the last 1 mile to my home, the 12vdc fan on my tranny cooler kicked-in. This is not uncommon when coming-off of high speeds, to low speed stop and start driving.

When I pulled into the driveway, I heard the fan wind-up in speed [as-if a higher voltage had been applied to it], then it stopped-dead.

I found the 30 amp fuse blown leading to this fan.

This, too, was prior to plugging into shore power.

-And- none of the 3 - 25amp fuses on the PD 9270 blew during this event, but, it is my understanding that these fuses are to protect from a reverse polarity situation ...not sure if they provide any other protection.


So, back to your original post Neil, I, too, still have the same question...

A better understanding of how the system works would seem to lead to an answer to what could be used to achieve this goal and where to place-it in the line.

It also seems strange that none of the DC breakers tripped during this event.

If a person were to install a main breaker, what amperage would it be? There are also large in-line fuses that should probably work for this application.


Would be great to know if all of this could have been prevented.