Inverter "Locked up" Requiring Reset after loss of power

[robertj1961]

Charging the batteries today on a 110 volt line and set the amperage on the Mastervolt Combi accordingly (15 volts). The line I was using was GFCI protected and after charging for about 15 minutes normally the GFCI tripped.
We have the 200ah lithium batteries and there is not a dedicated yellow manual disconnect switch like some have that I have been able to find. Many of the Thor Vans have the yellow breakers that can be used to disconnect the batteries but ours does not. The mastervolt "combi" display was stilll showing absorption charging after the power "kicked off". Tried to reset the system by disconnecting the battery switch but this does not disconnect the inverter from the batteries.
Finally after much frustration called Mastervolt Technical support. Can not say enough good about "James" who is a tech there and stayed on the phone with me over one hour until the problem was resolved. Solution was to remove the positive lead from the inverter and then reconnect. All working normally again now. Seems that Thor should have installed a way to "turn off" or disconnect the inverter/charger. The switch on the inverter/charger does not turn the unit off. Only function is to turn the inverter part of the charger/inverter but does not completely shut down the unit so only way to remove it completely from power was to disconnect the battery.

[16ACE27]

Good info to know. Thanks for posting your experience.

[fourthgear]

Ya , thanks , just how did you connect to a MasterVolt & talk to someone ?

The Yellow Switch you refer to is called BSR Battery Safety Relay , its to protect the LI batteries , but can isolate the LI batteries if needed ( all 12 VDC. ) .

I have had issues with the ATS when switching to SP , They replaced the ATS back in May & have had only one issue since & the only way to reset the Inverter was that yellow BSR. The MasterVolt 3000 with 400AH system, in my case, would show it had 120VAC in , charging & in Absorption mode for battery charging but , no AC Voltage in the Coach , not from the LI Batteries or from SP , even though both were available, but not to the 120VAC Breaker Panel , it seemed to me the inverter , which has a auto switch over to SP when detected , was stuck , as you say , but not getting any SP to it , but if that was the case , why would the Inverter switch to SP pass through , if it was not there & stay stuck there if SP shut off . It doesn't show on the electrical schematics I have from Thor , but wondering if there is a communication from the ATS to the Inverter , inverter manual reads the Inverter automatically senses when SP is available & switches internally to bypass the Inverter for SP AC .

I could not get to speak to anyone or find a number that wasn't for a installer for their product & they referred me to contact Master Volt , I gave up , it seems the ATS & my system is working , but think there is an issue with the auto transfer with in the Inverter & if it does happen again , I will take some readings to see exactly what has Voltage & where .If I have any more issues with it , I will not be going back to the Dealer , heck ,by the time I get in for a appointment the warranty will be over

[robertj1961]

I was fortunate to get the right guy. Was on hold for over 30 minutes. Their technical service number is 800 307 6702. The guy who answered said he is supposed to have a case number from Thor before assisting but since it was late Friday would help me. He actually stayed on the phone with me 1 hour 20 minute until the problem was solved so really happy with their customer service and would be a mastervolt customer if for no other reason! He seems to understand how frustrating it can be getting service with dealers etc.
He was surprised my van did not have the yellow BSR switch and said it should have one somewhere for safety reasons to disconnect totally the batteries.
We discovered the simplest method to remove the power in my case from the batteries was to just disconnect the positive lead to the inverter. This is accomplished by removing the cover to the inverter by removing the two small phillips head screws, and then using a small socket wrench to loosen the screw to the positive battery cable. Keep in mind if anyone does this the wire is "hot" but according to the tech guy not a dangerous amount of amps/voltage but one should still use caution.
Not sure if the transfer switch contributed to the problem but in any case removing power from the inverter solved the problem. I have access to a 50 amp plug I used for the class A and will use that in the future to power the van for charging or other purposes. The 110 amp that I was plugged to at the time was on a GFCI circuit and when it kicked out is when the problem occurred.
I am now researching how to add a BSR switch or something similar that would work so if anyone has ideas please advise? Seems that Thor should have added this to all of these or at least had some method to remove totally power from the inverter. Turning the master battery switch still leaves power (from the batteries) to the inverter for some reason.

[fourthgear]

Not a big deal to install one , but not sure how that would effect your warranty , I think Thor skimmed on them with the 100 & 200 AH LI Systems or they were supply problems .

So you plan on getting an adaptor for 50 to 30 Amp system , good to have any way when camping , never know when a place may only have 50 AMP plug ins .

Ya , I got familiar with the Inverter & systems from the first day I purchased the RV , didn't have a choice , read all I could about them & to me it all came down to the Inverter , but GRV Changing out the ATS has been working , but the one time it locked 120VAC out last month tells me there may be more to it .

Does your Inverter have indicator lights on top ?

[robertj1961]

I have the lights on mine like yours but you can not see them unless removing panels on the top of the bed on the driver's side. That would be a good way to monitor if you could see them...
I have used the 50 amp with adapter already and it works fine. The one time I used the 110 closer to my house for convenience is when I had the problem but won't do it again. Should not have been a problem according to Mastervolt. I adjusted maximum amps down to "10" on the "combi" display but still popped the GFCI breaker for some reason. I have a refrigerator on the same 110 circuit so suspect that may have contributed to it.
It is possible that the problem will re-occur on the 50 amp plug but only time will tell I suppose.
Good point on the warranty however and don't want to give Thor an excuse to deny if I have future problems. Mastervolt guy seemed to think it important to have a disconnect somewhere for safety reasons so you would think Thor would have installed.

[sthursto]

"Charging the batteries today on a 110 volt line and set the amperage on the Mastervolt Combi accordingly (15 volts). The line I was using was GFCI protected and after charging for about 15 minutes normally the GFCI tripped."

Not sure, but I think you are saying you were running a 110 line (15volts) to the RV to give it power to use the converter side of the inverter/converter to charge the batteries. TIP: using a larger bigger gauge extension cord makes a big difference in getting the most power to the RV without loss down the line or some heating thus it reduces the chance of tripping the GFCI.

I can run from a GFCI outlet in my garage to the RV at the curb without tripping the home breaker so long as I use a heavy duty extension cord.

Hope that helps folks.

[robertj1961]

Thanks for the tip and totally agree. The cord has to be up to the task! I had it on a very heavy gauge cord that I had purchased some time ago for a 5th wheel so don't believe that was the issue but agree could have been. For some reason, that particular GFCI has tripped before during storms etc and have replaced it but still seems like it is having problems.

[EA37TS]

Originally Posted by robertj1961

Thanks for the tip and totally agree. The cord has to be up to the task! I had it on a very heavy gauge cord that I had purchased some time ago for a 5th wheel so don't believe that was the issue but agree could have been. For some reason, that particular GFCI has tripped before during storms etc and have replaced it but still seems like it is having problems.

There are many RVs that don’t like to be plugged into a GFCI circuit. Hundreds of posts regarding this issue on this and other RvV forums.

[robertj1961]

Originally Posted by EA37TS

There are many RVs that don’t like to be plugged into a GFCI circuit. Hundreds of posts regarding this issue on this and other RvV forums.

Could be but have used them before on three different RV's and first time to have a problem.

[fourthgear]

Originally Posted by robertj1961

Could be but have used them before on three different RV's and first time to have a problem.

GFI's do have a service life & tripping for no reason is one clue it could need replacing .

[robertj1961]

Originally Posted by fourthgear

GFI's do have a service life & tripping for no reason is one clue it could need replacing .

Good Point. I replaced it within the last six months thinking the same thing. I have a garage refrigerator on the same circuit and now suspect it could be the problem. I have decided just to not use that location again to power the van because don't want to go through the hassle of disconnecting power to the inverter again if the GFCI trips. Hard to believe Thor didn't provide a better way to remove power to the inverter and may call them just to make sure.

[fourthgear]

Originally Posted by robertj1961

Good Point. I replaced it within the last six months thinking the same thing. I have a garage refrigerator on the same circuit and now suspect it could be the problem. I have decided just to not use that location again to power the van because don't want to go through the hassle of disconnecting power to the inverter again if the GFCI trips. Hard to believe Thor didn't provide a better way to remove power to the inverter and may call them just to make sure.

I would be interested to hear what Thor has to say about it , seems to be a safety component .

inrush current from from a refrigerator Compressor starting can play with GFI's & trip them . The more expensive panel circuit breakers seem to handle it better .
It's sometimes difficult to trace what is tripping an GFI Receptacle & it may not even be a GF. A dedicated Circuit should be used for SP for the RV , as you have mentioned .

[sthursto]

Could you just disconnect the inverter at the battery instead of at the hard to reach inverter? Seems like disconnection one wire would do the trick to reset it.

Just a thought
Scott

[robertj1961]

Originally Posted by sthursto

Could you just disconnect the inverter at the battery instead of at the hard to reach inverter? Seems like disconnection one wire would do the trick to reset it.

Just a thought
Scott

That was my first though also but the batteries are mounted in front of the rear axel on the outside and underneath the van with more difficult access and would require more "gymnastics" than just disconnecting the positive lead to the inverter itself but thanks for the thought.
"Hoping" this is not an ongoing problem and haven't had the problem occur since not using that outlet on "that" GFCI. I am using a GFCI outlet on a 110 to charge batteries at another residence from time to time but have not had any issues there but the GFCI has not tripped there either.
I agree that the "dedicated" line would be the preferred location but don't always have that option at our other residence.

[robertj1961]

Called Thor Customer Service center to find out if there was a way to disconnect the inverter/charger from power that I was not aware of. Ended up not being much help (big surprise). After providing my vin number, was advised that the inverter could be removed from power using the switch on the inverter.
I explained that I had spoken with Mastervolt who confirmed the function of the switch is only to turn the inverter function "off" but had no effect on charging or turning the unit "off". Representative told me "well it's their inverter so I guess that's how it works...My thought at this point was well Thor installed it and I guess Thor does not know (or care) how it works...

When I inquired about the yellow disconnect switch that mine does not have, she advised me that even if I had those customers should never "touch them" unless to reset in the event of a problem.

I asked if I installed a switch to disconnect power to the inverter could it effect warranty? She said she was not responsible for that department and only a "service center" could determine that.

The good news is that I have plugged into a 110v GFCI outlet at a different location several times now without any problems whatsoever.

Will probably add a switch when I get some time to disconnect the power to the inverter at some point. Mastervolt technician seemed to think there "should" be a way to disconnect battery power from the van/inverter for safety reasons but obvious Thor apparently didn't think it important.

[RonRM]

Nice summary.

Makes perfect sense 'no way to disco the batteries for safety'...plays right into Thor's 'Safety Third, Profits First' slogan.

Did the MasterVolt guy say it mattered if removing the positive lead or negative lead mattered?

If you can get away with removing the negative lead, then putting in a disco switch at the shunt, between the two negative cables and the shunt, (providing those cables are home runs to the battery posts -needs verification) would serve both purposes...disco the batteries for storage/safety and reset the MasterVolt from time to time.

I'm surprised he went with the positive lead, that is super dangerous...if you had touched any frame grounded metal...you would weld the wrench/socket with all 200amps from the batteries. Safer to remove the negative first as it's directly grounded to the chassis...no sparks if you touch metal with the wrench on metal.

Attached - a clip from the Thor owners site for a 2023 20L 200amp Relion schematics

Ron

[16ACE27]

Originally Posted by RonRM

Nice summary.

Makes perfect sense 'no way to disco the batteries for safety'...plays right into Thor's 'Safety Third, Profits First' slogan.

Did the MasterVolt guy say it mattered if removing the positive lead or negative lead mattered?

If you can get away with removing the negative lead, then putting in a disco switch at the shunt, between the two negative cables and the shunt, (providing those cables are home runs to the battery posts -needs verification) would serve both purposes...disco the batteries for storage/safety and reset the MasterVolt from time to time.

I'm surprised he went with the positive lead, that is super dangerous...if you had touched any frame grounded metal...you would weld the wrench/socket with all 200amps from the batteries. Safer to remove the negative first as it's directly grounded to the chassis...no sparks if you touch metal with the wrench on metal.

Attached - a clip from the Thor owners site for a 2023 20L 200amp Relion schematics

Ron

Fits right in with the mindset that the positive lead is what really supplies the "juice".

[robertj1961]

The mastervolt technician advised me to disconnect the positive terminal when it would have been just as easy to disconnect the negative. I asked him about the safety of that and he said it was DC and not dangerous but to be aware I would be holding a "hot" wire and not touch metal with the wrench (or wire). I could be too trusting but took his word for it on being safe. He said if I hit metal I may see sparks but it would not be dangerous. When I loosened the screw holding the positive terminal, I noticed a light spark at the terminal when somewhat loose and then the inverter fan came on and appeared to reset the inverter. I actually never had to completely remove the screw or terminal. I think when I loosened the screw I lost the connection momentarily enough to reset it. He told me that was what I needed to do for the reset. After that all was working normally again.

I replaced a Magnum Energy (2800 watt) on a motor home I had a few years ago and remember that the instructions for the install said "it is important to hook up the positive cable last". Did not have any problems with that installation but of course had the batteries disconnected when doing that. The manual for that device however did instruct removing the positive terminal and reconnecting for a reset.

I admit that electronics are not my "specialty" but just wanted to get this problem resolved and was fortunate the Mastervolt technician was willing to help. He admitted the proper procedure would have been to contact Thor but was lucky to get someone on the phone with some appreciation for the customer service. This guy actually spent well over an hour on the phone with me on a Friday afternoon so can't say enough good about Mastervolt customer service.

We all probably know a phone call to Thor would have resulted in being referred to a "service center" to wait a month for an appointment for a 30 minute "fix".

Reading a little "after the fact" confirmed the dangers of AC current compared to DC. As little as 25 volts AC can be dangerous from what I have read but feel free to share information if I am wrong.

At some point, want to add a switch in case this happens again. The way it is wired and set up now thanks to "Thor", it is going to be a real "pain" to disconnect power from the batteries themselves to install a switch. The batteries are hard to get to and remove from what it looks like. Hopefully someone better with the electrical side of this can provide a simpler way to install a switch because don't really want to disconnect the "hot" positive cable to the inverter again unless absolutely necessary!

[16ACE27]

Not dangerous? Tell that to the guy that shorted the wrench from the positive terminal to ground and it welded in place drawing maximum current from the battery bank until the batteries overheated and exploded.

That Maservolt technician needs to pull his head out of the lab and into the real world environment.