12V DC system shutdown

[Old-Biscuit]

Originally Posted by okmunky

Oh (expletive deleted)! I just did and the 12V including the converter went dead. Back to searching for a fuse.

I was afraid of that
Converter dead..that is only because NO 120VAC In

Issue is NO 12VDC from battery
Find battery POS Cable....follow it to the In-line fuse (Or DC Circuit Breaker)
They are usually close to battery

[twinboat]

The converter powers the RV 12 volt system from it, directly to the fuse panel.

Between all of that is a battery disconnect solenoid/relay and a fuse/breaker, which will be near the battery.

Converters don't need breakers because they are limited to what ever current they are built for. No need for a 60 amp fuse on a 50 amp converter.
The fuses on most converters are to protect it from reverse polarity.

Batteries have thousands of amps in them. That's what melts a wrench. They need breakers, so a short near the fuse panel doesn't melt the wire back to the battery.

[Ndrorder]

Another form or RV circuit breaker shown in the link. This one is auto-resetting which you don't have. The ones that don't auto-reset look the same, but have a little button that pops out when it trips. Push the button back in to reset.


https://www.amazon.com/Bussmann-CBC-...RG7HR2MENXEJ25

[okmunky]

Batteries are at 13.99 V. Converter lights are on when plugged into shore power. Here is all that. I’ve found so far. I am looking for cardboard so I can go under the rig.

The last picture is the guide for the wiring behind it. See second pic. Notice there is none of the resets that are shown on that panel.

[JHinman]

I had a similar problem recently. I had been making some minor modifications when the DC system died. I re-checked everything and could not find the problem.

It turned out to be corrosion at the negative battery cable Connection to the battery. It was pure coincidence that that particular failure occurred as I was doing some unrelated things to the electrical system.

That is such a common problem that it should be one of the first things checked.

[Ndrorder]

To troubleshoot requires a hand held volt meter.


1. Disconnect shore line and turn off the generator.
2. Measure voltage at the batteries for reference. Needs to be more than 12 VDC.
3. Measure voltage between center bolt labeled Coach Bat and ground (little screws in the lower right corner). Should be same or close to battery voltage. If not, check the voltage into and out of the disconnect switch (first picture). Will require removing disconnect from the wall to get to the wires in the back. Measure relative to ground, not between the two connections. Should be battery voltage on each lug of the switch. If not, switch may be defective.

4. Measure voltage between lower lugs of breakers (gray little boxes in the middle) and ground. Should be same or close to battery voltage. If not, look for button on side to reset the breaker. If no button, good bet that the breaker is bad.
5. Measure DC voltage into the converter. Should be same or close to battery voltage. If not, check the 2 30 Amp reverse polarity fuses in the converter.


Good luck.

[twinboat]

Nothing under the copper bars, where I marked with blue lines.

[okmunky]

No, those are bolted to something solid.

[Bob_C]

Next trip to Yuma, stop by Walmart or Harbor Freight for a meter....best I can do at this point....why are changing the converter?

[Old-Biscuit]

Originally Posted by okmunky

No, those are bolted to something solid.

twinboat has marked the 2 DC circuit breakers
According to the diagram the closest to fuse board is CONVERTER and the other one is for INVERTER

Both show MANUAL Rest button on end of breakers
They are small buttons and with your set up ---hard to reach
No small buttons then they would be Auto Reset Styles

Check voltage on both studs (voltmeter probe on studs and other probe on ground)
Upper one should be HOT
Lower one should be HOT if the DC Circuit Breaker is reset/good breaker

Far left on fuse board next to that White wire (ground) is a K1 Relay....in photo looks like case is damaged

Also that Blue 15A fuse top row--right side--doesn't look like it is properly inserted in fuse clips

[okmunky]

I know it’s hard to see in the picture with all the wires but my coach does not have inverter and converter resets in that panel.

That fuse was missed placed but I did that after the DC quit, to check to see if it was blown. I have fixed it. The damage to that little black box (at K1) I did trying to to remove it from the panel after it quit

[Old-Biscuit]

the 2 devices twinboat marked with the blue lines ARE DC Circuit Breakers and according to that fuse diagram you posted they ARE for converter and inverter


the dc circuit breakers are those gray boxes with the 2 studs
Upper buss bar is attached to one of the DC CB studs
Lower angled connections are attached to the other stud
DC is HOT to upper buss bar
With DC CB CLOSED...bottom stud is HOT to converter and inverter

Voltmeter...test both studs for DC Voltage
Red probe of voltmeter on stud...black probe on DC Ground
If DC CBs work......DC on both sides

[okmunky]

Originally Posted by Old-Biscuit

the 2 devices twinboat marked with the blue lines ARE DC Circuit Breakers and according to that fuse diagram you posted they ARE for converter and inverter

Those are missing in that panel. It came without them.

I'm thinking the problem is with the panel at the foot of the bed that has AC breakers and DC fuses for stuff that my RV actually has in it. I'll take photos of it, front and back, and post them tomorrow morning. The charger/controller plugs into the back side of that panel.

I know I had a mouse in there when the old charger/converter started failing. There may be some chewed wires. There is now steel wool in the hole that rodent was using. Why doesn’t the factory seal stuff better?

[Old-Biscuit]

Originally Posted by okmunky

Those are missing in that panel. It came without them.

I'm thinking the problem is with the panel at the foot of the bed that has AC breakers and DC fuses for stuff that my RV actually has in it. I'll take photos of it, front and back, and post them tomorrow morning. The charger/controller plugs into the back side of that panel.

I know I had a mouse in there when the old charger/converter started failing. There may be some chewed wires. There is now steel wool in the hole that rodent was using. Why doesn’t the factory seal stuff better?

So the pictures posted were NOT yours???

No wonder thread went sideways


Mouse/chewed wires.....big problem
Definitely need to access the charger section and check it out