Magnum Inverter/Charger

[ernest917]

OK folks.... arrived at new CG few hours ago... COE park so I only have 30 amp power....

Plugged in coach..... having issues with inverter showing a fault “Tfmr Overtemp” and shut off ..... apparently after it cools it will then turn back on.... cycle has been containing.....

Normally, unit shows abt 34 amp of bulk charge and then goes to absorb then float - now showing 49-50 amps and stays at 50 amp...

Any ideas?????

[btritschler1437]

Did you change the shore power from 50 amp to 30 amp?

[ernest917]

It’s set up to do that automatically...

FYI: got up this AM, and everything’s back to normal - it’s currently in “float” mode and seems to be behaving itself....

[formerFR]

Originally Posted by ernest917

OK folks.... arrived at new CG few hours ago... COE park so I only have 30 amp power....

Many COE parks also have full hookups and 50amp service, just sayin...


having issues with inverter showing a fault “Tfmr Overtemp” and shut off .....

had this happen with my Magnum last year - this is the 'TRANSFORMER OVERHEATING' message. The transformer is large and heavy and has two different FANS(simple computer type fans) that are designed to help cool it. It's quite possible that one or both have seized up and not providing the cool down it needs. While you came off the road and 'plugged in' before it happened, it may well be that it's just coincidental and may have started doing this even if you hadn't. While the temps fell overnight, the 'overheating' issue went away, as well as due to it is only 'passing thru' power, and not actually 'inverting' while you are plugged in.

Magnum Customer Service, via email or call, is good about helping out....

enjoy ! : )

[btritschler1437]

Per the manual. "This fault message is displayed when the TCO (temperature cut-out) opens and causes the inverter to shut down to protect the internal power transformer from damage. When the TCO has cooled down, the inverter will automatically restart and resume operation.

Remedy: If the fault continues to occur, disconnect all the inverter's AC output wires and reset the inverter. If this fault does not clear after doing a reset, the inverter may require service.

[formerFR]

I had these symptoms, at first, then started getting a 'FET OVERLOAD', kicking OFF the inverter. Eventually had to replace the unit at INVERTER SERVICE CENTER< White House, TN...who did a great job, in a matter of an hour or so.

[ernest917]

Got the manual..... read those pages....

Also as a frequent user of COE parks I’m aware that some have FHU with 50 amp....

This one doesn’t.....

Matter does seem to have corrected itself..... been good all day.....

[ernest917]

Well problem is reoccurring occasionally so I called Magnum tech support.....

First issue was instead of the preferred 14.6V I’m showing 11.2V up to 13.3V.... In addition, instead of a normal 34amps I initially (upon plugging in) I’m showing 51amps.... Once bulk charging finally gets to “float charging” I’m at 13.3V and 17amps....

Issue three - tech had me unplug shore power and then turn inverter on.... showed nothing on monitor screen and wouldn’t turn on....

Tech then stated that “your batteries are dead”

Great......

Second issue -

[formerFR]

you may simply have a bad cell, or cells, in one of more of the batteries....mine had this issue, or similar issue, as the Inverter would continue to get 'knocked off' everytime I simply used the microwave, or even later just when the fridge's compressor kicked on...

after a lot of aggravation and searching, thinking that it could not be the batteries since they showed fine when charging, and even measured 12.8 with my voltmeter, I finally got out the 'ol specific gravity reading tube and found that two of the 4th battery cells were reading 'very low'....
what was happening was that when the Inverter would 'demand' the voltage/output of the battery bank when the fridge or microwave was on, the sudden 'rush' of amps drew down the suspect battery/cells to the point they could not supply a 12v output, and the Inverter is designed to 'shut off' when this happens, basically thinking that you have cut off it's power.

I removed the battery, reconditioned it(drained, refilled with distilled water, ran thru several full charge cycles, drained, filled with new battery fluid, ran thru several full charges), and the battery was then back up to par. I reinstalled it, and then the Inverter had no more issues.


Batteries are fickle, even when it 'looks' like everything is kosher.