‘14 Palazzo inverter bay devices - problem...

[TurnerFam]

I have a new issue that started yesterday...

after some travel, I stopped and set up for the night, only on the Inverter... pretty normal and everything worked fine, until...

an hour or so later I lost all power, at least inverter powered items like the sat receiver ... which was the tip off to a problem. Went and looked at the inverter panel - the first time I’ve ever seen it just BLANK - nothing.
Strange, yes... went out and reset the inverter. Then the inverter panel was back on, but showed the inverter as OFF... only DC 12.4 Volts showing.
I pushed the inverter to ON, but it only ‘flickered’ ON and immediately went back off, and I noticed my lights flickered at the same time. What?
I pushed it on again, and this time not only did it immediately go back off, but all the 12v lights with it... then the screen went totally blank again.

I tried to push the ‘Use’ switch by the door - nothing.
I went out and reset the two BUSS Fuse breakers in the battery bay, tried the ‘Use’ switch again, and lights came back on(?)...

I called Magnum and they suggested that removing the top ‘phone type cable’ from the side of the inverter would probably override the issue, temporarily, since it is the tie in with the ‘Use/Store’ 12v disconnect switch. That worked - but an hour later, it all went dead again.

Today, I called Thor - who said it was probably the 12v disconnect ‘coil’ going bad, as it would work for a while, then not.
Sounds reasonable.... especially as on the generator or shore power, the inverter stays ‘on’, passing thru power.

Let know if you have any other ideas, and make sure the correct ‘device’ is what I’m looking at replacing(the first two pictures)... AND any ideas of what the other items are/do in the inverter bay(the other pictures)

[JamieGeek]

Should be easy to check on the coil if you have a voltmeter handy (check if you still have 12V coming out of the coil when you lose power, or check the 12v input to the inverter when its dead).

[TurnerFam]

I'll check that before I replace it, just as the Thor after-hours tech suggested, and also try to research what these other devices are that aren't found or explained in any of the original paperwork, or electrical schematics from Thor.

What they DO show on the schematic, at the general area of the inverter bay, is a list of 4 fuses, each of which has a size and description of it's usage: (pic shown below)

5a fuse - Inverter cut off
15a fuse - B.I.R.D / Battery Disc / Radio mem
30a fuse - Bunk lift power
5a fuse - Inverter fan power

[TurnerFam]

it looks more like this 'salesman's' switch controls the 'RV CUSTOM PRODUCTS' latching relay, in the bottom photo. The information online shows that this is a momentary switched device that is a 12v Battery Disconnect, making use of an internal magnet to 'open'(STORE), or 'close'(USE) the internal contacts.

It sounds like either the physical switch is failing, or the device itself is not holding the contact. I've noticed that while on the engine Alternator, with it's charging to the battery bank, I have no problem keeping the Inverter ON...and inverting. It's only when the coach is sitting idle, off-grid, that the Inverter goes OFF after a while of inverting, even though the battery levels have only fallen to 12.4 or so, no where near the LBCO setting of 11.5. Also, the LBCO generally gives you a 'FAULT' and RED Light if it has cut off the inverter due to low battery levels, then automatically comes back online once the battery levels have reached back to 12.5.
In my situation, the inverter goes OFF, though there is no fault or warning or alert, and will not come back ON, without the Alternator in play, or on generator or shore power.

I can't say for sure that this device is part of the issue, because I don't necessarily lose all 12v items when the Inverter goes OFF, but I've tried to reset the Inverter several times, and I've lost ALL 12v power on several of those occasions, almost as if the Inverter's 'restart' is somehow impacting the whole 12v system. (?)

[TurnerFam]

one is a White Rodgers
the other is a Trombetta

[TurnerFam]

today I performed a test - off-grid, with no alternator, shore, or gen power...

the batteries where at 12.6volts
the inverter was 'off'
12v disconnect was 'off'

A) Load test
- 12v disconnect on, lights now working
- Inverter to 'ON', everything looks normal, Inverter is 'inverting', with little to no load

- I opened the fridge, and the light came on - still inverting, no issues
- I THEN turned the fridge controller up, the compressor came on, the 12v lights flicker in the living room, and the Inverter IMMEDIATELY went OFF - not normal.

- I turned the fridge back off
- I then turned the Inverter back to 'ON', and it went back to inverting
- I opened the fridge and turned the controller up, and the Inverter AGAIN went off
-- but this time, the Inverter also gave a FAULT: Internal NTC Fault, and a red light
-- the manual says that this is an internal temperature spike fault, and to rest the inverter by holding the inverter's button on the unit for over 15 seconds, then it should clear when the inverter is again turned back ON
-- the reset worked, and turning the Inverting back on at the Magnum panel worked fine - the Inverter was now ON again...

B) I decided then to perform a 'minimum' Load test, without a microwave or fridge compressor involved - but more smaller and 'electronic' 120v loads.
- with the inverter still ON, I turned on the main TV - everything continued fine.
- added a table-top fan, fine.
- added the radio, and 120v sound bar and bass box, still works fine, still inverting.
- added another couple of 120v fans, and the rear TV satellite receiver, all still fine.

- now, I decided to add another 'larger' load - a small vacuum. Nope, 12v lights flickered again, and it kicked the inverter OFF...


These two tests seem to identify an issue that I believe is related to the 'amperage' draw for devices that have compressors or similar motors, such as the microwave, fridge, and vacuum. While this 'could' be a fault within the Magnum inverter, I'm also wondering if it 'could' be a result of a failing '12v D.C. cont. coil' - which may be designed to handle the 'surge' of amps when a device is turned on thru the 12v systems, which also leads to the Inverter.
I may be way off on the usage of the 12v dc cont coil, otherwise the WhiteRodgers or Trombetta devices, but it seems plausible that either of these 'failing' could result in them working fine for smaller loads, but not for the spike of larger ones, as the 'flicker', or quick loss of 12v power, may make the inverter think that there is none, causing it to go offline.

I'll be conversing with Magnum tomorrow, to get their feedback and ideas. While I'd rather more easily change out a d.c. coil, it may be one of those Magnum internal issues - not such an easy change out.

[JamieGeek]

The lights could also be flickering because turning on a larger load causes the inverter to "hit" the battery hard for an instant until the inverter faults (which would indicate the inverter).

I would think that if the solenoid was bad it would cut out completely and cause the inverter to reset. However, if the solenoid is somehow compromised such that its providing some resistance (e.g. one of the connections melted or something causing a small contact surface area) a higher current draw would lower the voltage provided to the inverter causing that to wig out (although I would suspect you'd get some "low voltage" fault on the inverter in that case).

[Beau388]

I am not familiar with the Magnum inverter but on my Xantrex XM1000 when it faults the inverter displays the reason for the fault on the inverter panel. It does sound like low battery voltage under load. If you know the battery battery bank is supplying sufficient wattage, I would check the battery cable lug crimps, corrosion at cable ends and the tightness of the 12 volt connections. Look at the circuit breaker and fuse connections especially.

[TurnerFam]

I spoke with both Thor and Magnum today.

Thor thought that the idea of a 12v D.C. WhiteRodgers or Trombetta coil going bad might be a cause for the Inverter losing power/cutting off, although trying to get an explanation of 'what' these coils are installed for is not readily known, at least no by the phone tech. He sent over some 'harness wiring' diagrams, but they really don't show the devices, or any explanation. Replacing a $50 to $75 coil is not a big deal, but why if you don't need to, or figuring out 'which' of the two might be the one.

Magnum seemed to think that the symptoms certainly give the impression that the Inverter is losing 12v input, and therefore shutting 'OFF'. Since it will power back ON immediately thereafter rules out a Buss breaker or fuse.
The interjection of the 'flickering' of 12v lights also makes it seem as it a lose of 12v power, even if just for a moment', might be the problem.
Now, the first idea was that the battery bank might not be holding up to a 'sudden large draw' and dipping down enough that the Inverter thinks that it's either lost all 12v power, or it has dropped enough to trip the LBCO, even if just for a moment, and even if the battery levels show at levels that would never cause it, otherwise, and even if the Inverter didn't show a 'Fault'.
I don't really think that this is plausible, as the panel has never shown the battery levels below 12.5 or so, EVEN with many 120v items in play, while the inverter is working. The 'OFF' action happens so quickly, that the panel does not show any 'lower' voltage number, even if so.

I am still leaning toward a bad 12v d.c. coil, but 'which' one is the question.

I've been told to apply a voltmeter, on the DCV setting, to both sides of the 'inputs' of the coil. I'm not a voltmeter experienced user, and probably don't have it set correctly, or know what 'response' to really be looking for. Or, should it be set to 'ohms' to measure the correct resistance that the coil is needing to handle?

Maybe someone can walk me thru the process. I imagine you want to measure this when the inverter is OFF, and when it's ON, as well as the moment 'when' you apply the larger draw?

[TurnerFam]

Originally Posted by Beau388

I am not familiar with the Magnum inverter but on my Xantrex XM1000 when it faults the inverter displays the reason for the fault on the inverter panel. It does sound like low battery voltage under load. If you know the battery battery bank is supplying sufficient wattage, I would check the battery cable lug crimps, corrosion at cable ends and the tightness of the 12 volt connections. Look at the circuit breaker and fuse connections especially.

exactly, as this is what I told Magnum - I 'normally' see a 'FAULT' and some explanation or Fault Code wording - but in these situations I'm not seeing any other than 'OFF' and the current DC Volts reading, just as if someone reached up to the panel and pressed OFF.
This leads me to believe that it is losing all 12v power, even for just an instance, which cuts it to OFF mode.j
Batteries? Possible. I will check the voltage readings for each, and also the tightness of the connections, and possibly try to read the volts WHEN I apply the large load on the inverter and it cuts off. We'll see.

[javelin]

Just happened to look in this forum area and noted your inverter failure situation. Thought I would add my 25cents worth (may not even be worth that though).
Since I am not familiar with your coach DC configuration this is just my “off the cuff winging it” comments .......and see what happens:


Typical inverter 12VDC feeders I thought would be wired directly off the coach battery via a suitably sized inverter fuse and conductors, depending on inverter size etc. (i.e. 200 Amps+ fuse probably). So if that is true there should be no inverter DC feed current even passing through any set of relay contacts (latching or otherwise). If for example, the inverter was connected on the coach load side of the RV Custom latching relay......that latching relay would have to be rated for the load current of the normal coach DC loads plus the inverter. Not to say the relays can’t be rated for those load currents, but I would “speculate” the inverter is a direct tie off the coach batteries with its own fuse for protection and disconnection if required for service. So my “guess” (Similar to a few previous folks) is your coach batteries; clean/tighten the terminations of the inverter connections on the coach battery and at the inverter also.


Regarding the volt meter testing of relay contacts.....you would put the meter + lead on the contact connected to the +12VDC coach battery and the negative meter lead on the other load side contact of the relay under test (most digital meters will automatically read negative too if the wires are reversed). Close the relay under some test load and the measured voltage should ideally be zero for a short circuit formed by the closed relay contacts. You could use an ohmmeter to measure contact resistance too, but only on dead circuits. The voltage reading is easier and safer for the meter. Maybe that was only worth a nickel?

[TurnerFam]

its probably a couple of short cells in one of the batteries, but also look at this battery wiring diagram Thor just sent over - there is an ‘ISO RELAY’ connected to the battery bank and inverter via the Inverter FUSE....
but they can’t teally explain ‘why’ it’s there...

what say you?

[javelin]

Well, when I first saw your picture of the battery bay wiring I thought OMG I would hate to trace something in there......the diagram is much better.

The DC current feeding the inverter takes the shortest route from the batteries. So the ground side is obvious......and the +12v side of the inverter passes through the inverter fuse and goes directly to the +12v coach battery terminal. So that is the path to be checking for bad connections IMO. The double termination on the inverter fuse just ties the +12v coach battery to the rest of the coach loads.

[javelin]

I forgot to mention that the iso relay is your emergency start relay or what I call the "interconnect" relay on RV Custom Product BCC schematics. It ties the coach and chassis batteries together. Note that the +12V coach battery passes directly to the RV Custom latching relay through an 80 amp breaker to feed your "normal" coach loads.

[TurnerFam]

thanks, that info is valuable in trying to track down this 'issue'...

I know I have a 'momentary' Use/Store doorside switch, which should be controlling the RV CUSTOM PRODUCTS device, to shut off 12v power to the coach and the inverter.

I also have the dash AUX switch, which is a press-and-hold type switch to combine the House and Chassis battery banks. I suppose this goes thru the 80amp Buss Breaker and the WhiteRodgers 12v coil(?), which also has it's own separate 30amp inline FUSE attached, and PURPLE and WHITE secondary wires.(see below)

I'm still not sure about what the Trombetta 12v coil is for, as it's not even shown on this diagram... it sits above the other coil, under a large loom of wirings, and is very hard to see or get to, with maybe GREEN and BLACK secondary wires.
It's also covered in dirt/grime, although the WhiteRodgers coil is perfectly clean(?)(see below)

[JamieGeek]

I bet the trombetta is the "chassis battery disc" on the diagram.

I'd also bet that the white rogers is the "ISO RLY" on the diagram. (Note that the "ISO RLY" item shows one of the leads with "red tape" on it--does one of the wires to either have red tape on it?)

[TurnerFam]

good try, but the Chassis Battery Disconnect is a large manual ROTARY switch mounted on the wall in the battery bay... and it's wire shows as only 12" from the battery bank, not nearly enough to reach back into the Inverter bay when the Trombetta coil is mounted.

[TurnerFam]

I'll look at these closer today, as the 'tape' going to each of these wired devices, and the 'length' of each wire, should be good clues to identify and compare with this diagram.

[javelin]

Good morning. It might help to look at the generic schematic of the Intellitec battery charge control system and compare that to what you actually have on your coach. Since my coach uses the RV Custom BCC I don’t know which of your pictures is the “interconnect” relay (which connects/disconnects coach and chassis batteries under control of the BIRD); and which is the chassis battery disconnect. If you compare the Thor schematic, the Intellitec schematic and what you actually have on your coach you should be able to resolve which relay does what job. Once you do that mark them for future or draw yourself a diagram. I wonder if the Trombetta is actually your interconnect relay?


Just to clarify, the RV Custom latching relay will disconnect the coach batteries from the coach fuse panel (and probably your converter), but the inverter basically is always connected to the coach batteries (according to your Thor schematic) unless you pull the inverter fuse or disconnect coach battery ground or +12V cables. The intent I think is that the inverter high current needs comes from the battery string and not the converter through the RV Custom latching relay.....although that 50-100 Amp converter output would supplement inverter draw off the batteries......maybe why you said you had no issue when on shore power etc.

[TurnerFam]

thanks, I'll look over this...

and to clarify, I don't have a Converter, since the Inverter/Charger performs the same functions...
and my doorside Use/Store switch DOES remove 12v from the Inverter, turning it OFF,
which is identical to the problem I am experiencing(though, WITHOUT using the switch!)