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Superbee Jim · 03-26-2017, 07:49 AM

Is that done by the inverter? At the end of a day driving, if I check the voltage of both start and house battery banks, and if both banks have the same voltage, that would be great, but if the house bank isn't being charge, that is why I was thinking a jumper wire or a solinoid would solve having to run the gen when I stop for the day.

Kiawah · 03-26-2017, 07:50 AM

See my chart. A magnum performs three functions, a converter, an inverter, and a transfer switch. Your fault code indicates that there is some power coming back from the subpanel and output circuits.......into the output of the transfer switch. If you told me you were rewiring something in your circuit breaker box, I could understand how you might get that fault code.

If you have a ME3112, then your wiring would be slightly different than my MS2000 shown, in that you would have a 3 wire 240v in, and a 3 wire 240v out. I don't know all the devices you might have in your coach on the inverter, but it might be possible that a 240 volt device (like some older dryers were installed in coaches), has lost it's ground and backfeeding some power from leg A to leg B.

It is possible that the Magnum got confused during the switching off/on/off/on, and a hard reset should have resolved that.

It is possible that the Magnum is now defective.

What I would recommend to try is that you shut off the output of the transfer switch to the circuit breaker box. This would eliminate any possibility of a downstream circuit actually backfeeding into the transfer switch output. I'd then do another hard reset. At that point I would only turn on the converter, and see if the converter piece of the Magnum will start charging the batteries back up. That would give you 12v power, but you wouldn't have power to any of your circuits normally powered by the inverter.

Note that if your house batteries are too low in voltage, the Magnum converter will not charge them and you will have to get power into them by either an external battery charger, or running the engine alternator for couple hours. Once the voltage is up beyond the Low Cutout voltage, IF the converter is still good it should begin to charge the batteries.

If your converter works, the next thing I would try is to turn off the circuit breakers of all of the devices in the subpanel, and then turn on the subpanel master breaker. Make sure the inverter doesn't fault. Then one by one, start flipping the breakers in your subpanel, on those circuits normally fed by the inverter. See if you can determine which circuit is causing the fault.

The first chart depicts how shorepower feeds the circuits in the subpanel. Power comes into the main circuit breaker box, goes out to the inverter, thru the transfer switch, and then into the subpanel box. From there a number of circuits have power.

The second chart depicts how the inverter feeds the circuits in the subpanel 12v power feeds the inverter, and the inverter feeds the transfer switch, sending power to the subpanel box and it's circuits.

The third chart depicts how the house batteries are charged. Power from shore goes to the main circuit breaker box, out to the converter, and then to the batteries.

What I'm trying to get you to test, is to eliminate the possibility of power going out to the subpanel circuits, which eliminates the possibility of power coming back in as well (the indicated fault code). Hopefully the converter piece will work and charge the house batteries.

If you still fault code without anything connected to the transfer switch output, and after a hard inverter reset, then I'd suspect your Magnum is bad.

Kiawah · 03-26-2017, 08:37 AM

Quote:

For myself, Is it OK to jumper a big enough wire from the positive wire on the start battery to the positive on the house battery's while driving during the day, then disconnect it when done driving for the day rather than having to run the gen for a couple hours in the night to charge up the house battery's?

Superbee Jim,
You should probably have opened your own thread, as you don't want responses to your problem, mixed up with Band Aid 06. That would have to be a big cable, as you can get 300-400 amps current flow when connecting 2 battery banks together. Your alternator would be able to put out approx 160 amps itself. Check for a blown fuse on either end of the existing charge solenoid line, see my chart, or a bad solenoid (or what device your coach uses to achieve same thing). You can check with a voltmeter whether the power is getting thru, by measuring the voltage on both sides of each item (while the engine is running, the solenoid should be engaged).

Superbee Jim · 03-26-2017, 03:56 PM

Thanks, will start a new one

Band Aid 06 · 03-26-2017, 07:38 PM

Thanks for your advice. I will let you know if I have any luck. Which batteries supply current to the coach DC lights and outlets ? Chassis or house or both.

Dutch Star Don · 03-26-2017, 08:11 PM

"Band Aid 06".....You have a large 12 volt positive battery cable (red) that goes from the inverter to the battery bank. There is a large buss fuse mounted inline somewhere on the cable to protect the battery bank. If it's blown, it could be giving you the reading that you're getting. They often have a rubber cover of them.

Kiawah · 03-26-2017, 10:14 PM

Band Aid,

If it's the fuse that Don is suggesting is giving that misleading fault code, the fuse installed in the Tiffin is in your house battery bay. Look on the panel on the right of the batteries, just above the house battery disconnect switch. There is a fuse under a plastic cover. That's easy enough to get to and check to see if it's blown.

The left side of the fuse is connected to the battery buss, the right side is connected to a thick cable that goes off to the Magnum in the next bay.