mike-s wrote:
In addition to the individual circuit fuses, there are "reverse protection fuses" (Littlefuse type 257) in the converter panel, did you replace those?
I'm apprehensive about this "reverse protection fuses". If anything that could be used effectively for this purpose it would be a diode. There could be a bit of penalty in terms of loss (when using diode) as current flows through the silicon wafer, but I don't see this as critical when you are running sewage pump, or operating gas stove solenoid valve. Laboratory or life-saving apparatus perhaps would make sense.
But I will keep an open mind as we strut along this course.
OP indicated (contrary to what you said)that he did not get power from the pedestal. Hooking up the battery however gets some result. Plugging in to pedestal did not show any charging activity. With the battery hooked up by itself everything seems kosher.
Plugging in a battery in reverse could have serious consequences especially with all this high tech stuff that we have. By applying a reverse polarity to the charger/converter, the most vulnerable component is the charge sentry board. The only thing that protects this component is an ACB (automatic circuit breaker) mostly rated 15A. Because of the small components of the circuit board, the 15A CB would not serve a whole lot, something will smoke before the CB gets into action. This is merely for short circuit protection. It will reset by itself when the short is removed. You will find this in switching transformers in household PCs.
Possible cause of not getting an output from converter, hence unable to charge the battery is a failed sentry board. It doesn't matter what brand you have but the principles remain the same industry-wide.
When you energize the converter a signal from the sentry is sent to trigger the gate of an SCR to go ahead and charge the battery. As soon as the battery had reached a fully charged state, the sentry would send pulses to SCR to taper the conduction state thereby switching to low charging condition.
As I said, this card is easily exposed to reverse polarity, the instant you connect the battery the wrong way. Electrolytic capacitors in the sentry will not tolerate this error. Although smaller sizes can hold for a second, larger ones can not. They will explode, but they are made that way. . . you can tell with the slit on the case to allow them to explode. One reason to wear Hollywood style protective glasses when working around these things. (LOL)
However, the above doesn't explain why the blown 15A fuse at the
at the 12V load center. One plausible explanation is: you could have all or most of your appliances turned on when you applied the reversed voltage. A lot of this newer gadgets have reverse polarity protection diodes, some call them drain diodes. These diodes minimize the spike in the DC supply line when an inductive load is turned off and on. Magnet coils like relays are big culprits.
Drain diodes allow this decaying magnetic flux from the inductive coil to drain harmlessly. . . an unneeded energy. Shorted case of a diode could be seen as short circuit.
Lastly, all comments made here have their own merit one way or another. I don't want OP to come telling me (or others) that he followed everything he found here and yet no discernible improvement came about or even caused more damage.
The final say on what course you need to pursue is a decision by you and you alone. We are just trying our best to lead you to a possible solution.
Good Luck