Community Forums

Scott98 · 10-20-2021, 04:44 PM

Quote:

Originally Posted by geordi

Is the plug on the end of your shore cord able to be serviced? Before pulling it apart, you can use an ohm meter on the pins and on the other end at the transfer switch to see if there's a crossed connection. You should read good connection / near-zero ohms between the ground pin and green wire, the neutral (opposite the ground) and the white, and then either of the side pins and the black or red wires.

Then check for ANYTHING other than infinite resistance between each of the pins and all the others. If the meter flutters at all, you have a problem.

Not sure why your circuits are labeled "charge 1 and charge 2".... Are those the direct lines from the transfer switch / incoming power?

Regarding the male plug end, no, not serviceable. Coach side is the marine twist lock and never gets removed.
Will get the meter back out and work on the cord.
Thanks

RichardE · 10-20-2021, 05:39 PM

Hmmmm, I would hang my voltmeter on the input terminals to the MS2812. I can set mine to record max voltage. Then repeat the drill. It would help to know if the voltage is real OR something is amiss in the 2812. I was taught to try to cut electrical problems in half. If the voltage is real, then start back to XFER switch and test with meter again, then to cord.

You said you took the Hughes out of the circuit with had the same results. Just checking, to be sure the Hughes isn’t seeing something on initial startup and boosting the volts.

RichardE · 10-20-2021, 05:43 PM

Oh yeah.

The coach could have been prewired for two inverters, hence the two breakers.

paul65k · 10-20-2021, 05:56 PM

Have you called Magnum??
They have very good tech support and they can walk you through some troubleshooting steps

Archer2 · 10-20-2021, 06:27 PM

Now you have really gotten my attention. I don’t think anyone has asked yet so first, is this something that has just started or has it always done it?
Second what kind of coach is it make/model/year?
The two circuit breakers also make me wonder what is going on with those. Do you have 2 inverter/chargers?
Have you tried leaving the Charger 1 breaker off and just turn the charger 2 breaker on while monitoring everything just as you described? I am wondering whether for some reason, if it is true that you only have One charger, is the Charger 1 connected between the generator and the charger?
The other thing you said that makes me curious is while you had shore power to the vehicle when you turned on Charger 1 nothing happened and you read 0 VAC at the Magnum input. But when you turned on Charger 2 as soon as the built-in time delay that the Magnum waits after it sees shore power expired and the internal transfer switch switched from inverter out to shore power pass thru it instantly went from showing 118 to showing 184 and then it shut everything down. What that tells me is that when the shore power is connected through the Magnum transfer switch is when something funky on the inverter output is being connected and somehow disrupting a neutral circuit or causing a ground loop. Try killing the inverter OUTPUT breaker, connect up shore power and watch the Magnum input voltage. This is a really weird problem.

twinboat · 10-20-2021, 07:42 PM

Do you have a cord real ?

That's another point of connections.

Scott98 · 10-20-2021, 09:22 PM

Quote:

Originally Posted by Archer2

Now you have really gotten my attention. I don’t think anyone has asked yet so first, is this something that has just started or has it always done it?

Second what kind of coach is it make/model/year?

The two circuit breakers also make me wonder what is going on with those. Do you have 2 inverter/chargers?

Have you tried leaving the Charger 1 breaker off and just turn the charger 2 breaker on while monitoring everything just as you described? I am wondering whether for some reason, if it is true that you only have One charger, is the Charger 1 connected between the generator and the charger?

The other thing you said that makes me curious is while you had shore power to the vehicle when you turned on Charger 1 nothing happened and you read 0 VAC at the Magnum input. But when you turned on Charger 2 as soon as the built-in time delay that the Magnum waits after it sees shore power expired and the internal transfer switch switched from inverter out to shore power pass thru it instantly went from showing 118 to showing 184 and then it shut everything down. What that tells me is that when the shore power is connected through the Magnum transfer switch is when something funky on the inverter output is being connected and somehow disrupting a neutral circuit or causing a ground loop. Try killing the inverter OUTPUT breaker, connect up shore power and watch the Magnum input voltage. This is a really weird problem.

First happened in May of this year, one time only and then good. Started acting up about 2 weeks ago, three different parks.

Coach is a 2019 American Coach, Dream 45A. High end Coach with zero previous issues. Not my first Coach, or my first rodeo with Charger/Inverters and/or transfer switches. I’ve installed both in previous RV’s. I’m stumped on this one as well.

Coach has one Magnum Inverter. Both 30 amp breakers are wired at the main panel.

I did try leaving breaker #1 off and turning on just breaker #2 and I got the same results.

Travel day tomorrow so won’t be able to do further testing until late tomorrow afternoon.

Scott98 · 10-20-2021, 09:24 PM

Quote:

Originally Posted by twinboat

Do you have a cord real ?

That's another point of connections.

It does have a power cord reel. Cord just passes thru the reel and enters the Coach via the female, marine, twist lock connection.

Archer2 · 10-20-2021, 10:26 PM

Can you connect shore power but kill the Inverter output breaker in the Inverter sub-panel so there is no load on the output and see if the charger will stay on (I know that makes the inverter worthless but that’s not important now). If the charger stays on with shore power, then begin to turn the individual inverted loads breakers in the inverter sub-panel (microwave, entertainment center, refrigerator, etc) one at a time while continuing to monitor that the charger stays on. You may find that one of the loads will cause the input voltage to appear to go high and the charger will shut down. At least that will tell you that your problem is with the input circuit of the Magnum or in the load side.
Am I understanding that it is the case that when you connect to shore power that you cannot run your inverted loads like the TV unless you kill the inverter input breaker and allow the inverter to run supplying the AC instead of the shore power being passed-thru?

153stars · 10-21-2021, 07:51 AM

I and others mentioned owners have lost the brushes/contacts at slip rings in cord reel. The pics I have seen of one DIY repaired I was not impressed with just spring brass used to create brushes on reel ,at least of that brand reel. I'm surprised issues with the don't come up more often.
If marine plug to reel it could be bypassed. Or swapped to marine cord to test. Maybe you borrow one to run a test. Home depot has some butt connector lugs that match the amp rating to bypass reel.
The neutral contacts in ATS could also be an issue I replace one of my relays/contactor but it was small mechanical issue and could feel that it didn't pull in right. After replacing it. I had old one operating as it should in 5 minutes.

Scott98 · 10-21-2021, 05:45 PM

Quote:

Originally Posted by Archer2

Can you connect shore power but kill the Inverter output breaker in the Inverter sub-panel so there is no load on the output and see if the charger will stay on (I know that makes the inverter worthless but that’s not important now). If the charger stays on with shore power, then begin to turn the individual inverted loads breakers in the inverter sub-panel (microwave, entertainment center, refrigerator, etc) one at a time while continuing to monitor that the charger stays on. You may find that one of the loads will cause the input voltage to appear to go high and the charger will shut down. At least that will tell you that your problem is with the input circuit of the Magnum or in the load side.
Am I understanding that it is the case that when you connect to shore power that you cannot run your inverted loads like the TV unless you kill the inverter input breaker and allow the inverter to run supplying the AC instead of the shore power being passed-thru?

Drove the Coach 275 miles today, inverter on and running with no issues. Arrived, plugged in, everything fired up, passthru showing on the Vega monitor, Charger showed Float. Stayed that way again for about 3 minutes, then they both went out. Shutoff power at the pedestal, shutoff batt disconnects, waited 30 seconds, then turned everything back on. It all came online, difference is, I disabled the inverter on the Vega monitor. Charger stayed on, in float, and has continued to run for the past 3 hours with no issues. In coming power is present in all circuits, inverter and non inverter (washer/dryer/AC). Vega monitor shows that the inverter is disabled.

Archer2 · 10-21-2021, 08:17 PM

That would normally indicate that there is something faulty inside the inverter that is not forcing the inverter into standby and it is continuing to output power (out of phase) in parallel with the incoming shore power and that might explain it. But how can it operate reliably when on generator power? I am stumped. Please post a new thread when you figure out what is going on.

RichardE · 10-25-2021, 02:17 PM

Very unique problem, would love to know what the root cause was.

Archer2 · 10-26-2021, 09:59 PM

I know this is a kind of old thread but since it is unresolved as far as I know I figured I would take one more shot. I did some more research and this is what I think is going on.
This Magnum Inverter/Charger has two transfer switches internally. The main one does the switching that connects shore power to the A/C out “hot” connections but the second one is used to switch the neutral/ground from bonded when in Standby mode (shore power attached) to floating when in “Inverting” mode. I believe this relay or it’s controlling electronics is defective and not switching. So when on shore power the Neutral from the pedestal is allowed to float and so the internal protection circuits in the inverter shut everything down. I think the generator doesn’t have the same problem because it’s neutral and chassis ground are bonded at the generator and the generator ground is the same as the inverter ground (both grounds are the coach frame).
So I believe the problem is not going to be found in any of the shore power wiring I think the problem is that the Magnum needs a new A/C board.