Inverter issue

[DonnaB]

I'm posting the info below in the hopes that it will help someone else if you have similar issues. This is an article that Don wrote for the Newmar Fulltimers Traveling Times newsletter. This was an account of actual issues we had in October of this year and the resolution. So any of you who haven't yet....check your inverter wiring :-)




While traveling down Skyline Drive in Virginia this year we had a problem with the charging system on our coach. While on generator (boondocking) all of the sudden the generator engine speed dropped dramatically, and our amperage usage went down to zero. Now we still showed power available on the EMS display but the EMS was also showing 0 amps and the Magnum remote display showed a flickering red fault light with no charge function and with the inverter providing power to the coach.

Driving to the next overnight spot, the solar panels as well as the BIRD/alternator recharged the batteries. We parked at a campground with 50A power and I made the incorrect assumption that the charging issue was only from the generator. Wrong! In the early AM I discovered our battery level at 11.3 and all that power from the park was unused. Turning off the inverter allowed the batteries to recover enough to bring in the slides and off to repair we went.

First stop, Tom Johnson’s RV Center in Charlotte, NC. First thing the service order desk person asked, “Did you buy your unit from us?” That was a hint. They informed us that they had over 70 “actual” customers stacked at their repair facility and couldn’t help us for at least 2 weeks if not longer. Guess since I didn’t buy from them I wasn’t an “actual” customer. They wouldn’t/couldn’t even help to determine if the trouble was relay switch, inverter or other. Basically, I should have planned my problems to meet their schedule.

Camping World in North Charleston, SC agreed to see me the next morning at 8:00AM (very insistent about the time) only to find that CW schedules a team meeting on that day every week for a couple of hours, so no one that knows anything could help. Store mgr. tried but couldn’t log into the computer so had to take notes. I asked to make sure service notified me as soon as possible when they received the pictures I emailed of the problem just to make sure they had all the correct info etc. and never heard a word. I called them back, again, they advised they did receive the pictures, but had done nothing so far. I told them to forget the service request and I would take care of it myself.

Now for the point of this story….

Being somewhat OCD in nature, I decided to really delve into the problem to see what I could come up with. Upon opening up the plate on the inverter where the 120v AC is terminated I discovered the terminal strip for that connection was melted into two pieces adjacent to the screw where the ground to the pedestal was located. The wire insulation also was also melted. Taking that as a hint to what the problem could be, I called Magnum and they gave me a part number but told me that I would need to find an authorized service center to get that part or service. Magnum gave me the name and number of the closest center to my location at the time:

Inverter Service Center
102 SCT Dr.
White House, TN. 37188
(615) 285-0611
Email: Inverter Service Center

When I called, PJ Gonzales answered, said he had the part (used) but that he would send it to me if I wanted. He took my mailing address, and shipped it out that day, I received it the next day. My cost, $0.00. That is correct, zero. All he asked was to keep them in mind if I ever needed inverter troubles fixed in the future.

The terminal strip was the problem and was easy to replace. The melted terminal strip and wire was due to a loose connection on the terminal strip where Newmar connected the 120v service feed. While I was removing the terminal strip, ALL of the other wires connected by Newmar fell off of the terminal strip. Our coach is over 4yrs old so it is not unreasonable to assume that vibration and other factors are the reasons for those wires to be loose.

My suggestion for all is to spend the 10 minutes it takes to check those connections on the inverter and just make sure they are tight to avoid any potential problems. It is not too far from reality to speculate the heat caused by that loose connection could have caused much more damage than just melted terminal strip including starting a fire. I have set up an annual schedule for me to inspect and tighten those wires in the future.

Just as an added note about repairing an inverter. Most places that I talked to do not repair the inverter but ship it out to have the work done. Due to the excellent service I received, I would recommend Inverter Service Center to everyone.

[ottffss]

This - loose Magnum inveter 120v feed line terminal screws - is not a particularly "rare" issue and was reported up the Newmar production line some 4 years ago....

It is prudent to verify the tightness of these screw connectors..... Make absolutely certain the inverter is OFF and no power supplied to the rig.... Typically you will smell the burn as it happens, though the smell does dissipate fast once the burn breaks the connection.... This is the 120v feed into the inverter from the main 120v fuse panel... Access is through the small cover plate on the side of the Magnum.

I thought this was also reported on the irv2 site several years ago but I can't find any link to it - the thread must have gotten lost in the irv2 site conversion back then... Or more likely my memory.....

Pictures of the "problem" are below. The simple repair at this stage is to just clean and wire-nut the offending wires together. Tighten the rest of the terminal strip screws. The terminal block is NOT required and can be omitted using wire nuts instead.

[Luv2go]

Great posts, DonnaB and ottffss! As several other members have stressed in similar situations, you should occasionally check the tightness of these connections as well as connections to your circuit breakers and transfer switch (if you have one). Of course, make sure you have any inverter off and no shore power connections when doing so.

We narrowly escaped a fire while at my in-laws with our old coach, two of the wires connected to the neutral bar in the breaker box had loosened, the insulation on both wires was charred from overheating. One happened to go the the air conditioner, which we were using at the time.

["007"]

Thanks for bringing to everyones attention.
Another location to check while your at it is your load center 120 circuit breaker wiring and the 12V fuse wiring location near load center.
The transfer switch has wiring terminals that has stranded wiring that will loosen up over time and can cause major problems if wiring becomes loose under the screw heads. Surge protectors another location.
Change in temperatures, vibration will cause these problems.
Its on my list every spring to make the rounds for a trouble free summer.

[ottffss]

Quote:

Originally Posted by "007" Its on my list every spring to make the rounds...

In all the places 007 mentioned....

[dougburi]

With any issue that involves the inverter; my first call is to Magnum. They know what they are doing, probably can tell you how to fix it, have the parts needed, and will ship immediately. The repair facility "nightmare" scenario talked about by DonnaB is all too common. I keep a list of the 800 numbers for every component in my coach. When just about anything breaks on the coach, between the manufacturer of the item and myself - the solution is reached in 90% of the cases.

[wa8yxm]

I often say that many RVers have a few screws loose.. Those, the ones in the breaker box that hold the wires, the ones in your plug or outlet on the main power cord (I had a brand new power cord in my hand last spring.. the female Marineco connector fell off in my hand, not one screw inside it had been tightened)

I could go on, but I suspect.. You got the idea before you started this thread.

[ottffss]

Quote:

Originally Posted by wa8yxm ...Marineco connector......

Can you link a photo? I am not familiar with anything specifically called a "Marineco connector" as I only know Marenico as a general manufacturer of many types electrical connectors.... Thanks....

[DandS]

Marinco is a company primarily involved in shore power connections for the boating industry, but also markets products for RVs. Home Page | Marinco

[Norm4015]

I made a living repairing electronics (not RVs) and I learned many problems are caused by loose connections. Every time I buy a motorhome I spend about six hours tightening all connection on both 110 volt AC and 12 volts DC. That included the engine compartment, generator, HWH jacks, ATS, all circuit boards, 12 volt fuse panels, 110 volt circuit breakers and even the 110 volt outlets.

On my last two Newmars, fresh from the factory, I will estimate on each one I found about 30 connections that were not tight enough and probably 5 that were so loose they would have caused either intermittent problems or damage (fire).

My annual maintenance list includes checking for loose connections and each year I find about 5 more that need tightening.

[mr300ce]

Besides vibrations, heat from current flow causes connections to loosen, even in your S&B house.

[powerboatr]

thanks for posting this
i have a magnum inverter and took a look into the bay where its mounted....
my wires are tight now

thanks

[cj5 jeeper]

Loose connections caused a major meltdown on my transfer switch about 10 days into a three month trip last summer. I made temporary repairs that lasted until we got to a park that we were staying in for a couple of weeks, I ordered a new one from Tweetys, and of course the input and output terminals were in diffrent locations, which is par for the course. It took a little thought, and a little time to change things to make the new one work. When the transfer switch shorted, it must have sent a short through my inverter. One night about three weeks after the transfer switch was replaced we were watching tv when we lost power. Because of the transfer switch problems I knew it was connected, and I wasted a lot of time before checking the inverter and finding the problem, it got bypassed until we got home then I sent it in, and $400.00 later I put it back in. I was lucky, as I brought a charger for the toad if we traveled several days without driving it, so I used it to charge the house batteries when pluged in.

[Chickadee]

Hi Newmar Jockeys:

Mr. Know Nothing here again. So, if I want to start tightening all these various electrical connections, I unplug from shore power, then,.....then,.....what?? How do I isolate the whole electrical system from drawing on batteries so as not to get "zapped?" Won't closing the main breaker do the job so I can start checking and tightening connections? Will, shutting down ALL power affect ECM system.

Geeeze I hate being so inept !!, but I'm so worried I'm going to mess something up by not doing the correct thing in the correct order and or screw up computer controls and/or circuit boards, etc. etc.

Steve