Community Forums

CountryB · 09-23-2021, 11:25 AM

It has been said that one should not try to run modern electronics on a Coach with a square-wave (modified sine wave) inverter. Short of replacing the inverter with a true-sine wave, is anything I can do to help my electronics last?

My Coach has the Xantrex RV2512 model inverter (modified sine wave) and it came with a residential refrigerator (in 2005).

The original fridge was replaced by previous owner, and now the digital display on the replacement fridge is going bad. I'm going to replace the display - but I'm wondering if there is some device (to smooth-condition the power) that I could/should add at the fridge plug to help this one last longer. I have a small surge protection device at the plug now. This https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

The failing display could just be due to age (4 years old) and vibration, or Chinese build quality (and not the sine wave thing) - so I'm just asking for opinions.

rffowler55 · 09-23-2021, 11:50 AM

If it has been working for over 4 years I doubt it is the inverter. When we went to a residential refrigerator this year and, plugged it into our Magnum modified sine wave inverter, it was immediately apparent it was not going to work. I did buy an adapter that plugs into the outlet that trips like a GFCI if the voltage drops below or increases above a certain range hoping this would suffice to run the refrigerator but the modified sine was so erratic it would cut off too frequently to be considered dependable.

We replaced with a Magnum pure sine wave and it works as intended. There is a chance that the modified sine wave has a negative interaction with the refrigerator electronics but at 4 years of age a display going out could just be normal wear and tear based on the quality of our appliances these days.

dons2346 · 09-23-2021, 11:51 AM

The best thing to do is replace your inverter to run everything in the coach

The next best thing is to install a PSW inverter (1000 watt) to run just the refer

CountryB · 09-23-2021, 12:14 PM

That's an interesting idea Don.

Just Googling "1000W PSW" I see they are not very expensive - only a little more than I'm paying for the refrigerator's replacement display.

Is 1000W the right size?
Any brands you would recommend?

I guess I would need to run 12VDC wiring back to the battery compartment if the invertor is mounted near the refrigerator.

Would the PSW inverter add-on be able to switch between shore power and battery power as my Xantrex does now - or do you just run it on the batteries all the time?
I'll need to give this some thought.

Also, rffowler55 makes a good point - maybe I don't need to do anything... if the worse case is replacing a $150 display panel every 4 years.

twinboat · 09-23-2021, 12:23 PM

They make small inverters with pass thru relays and they also make separate stand alone inverter transfer switchs.

You can also just let it run on inverter power full time. The big inverter/charger will keep the batteries up.

96 Wideglide · 09-23-2021, 12:26 PM

Which make of fridge do you have?

Seems a lot of members who installed a certain Samsung model, with the factory MSW inverter, don't have issues.

CountryB · 09-23-2021, 01:23 PM

The refrigerator is a Frigidaire. Side-by-Side design.
Don't have the model number handy now - the part that needs replacement is the display (aka "User Interface") Frigidaire Part# 242058232 User Interface (OEM). Walmart had the cheapest price at $148

rffowler55 · 09-23-2021, 01:59 PM

Quote:

Originally Posted by 96 Wideglide

Which make of fridge do you have?

Seems a lot of members who installed a certain Samsung model, with the factory MSW inverter, don't have issues.

That is true and why I was saying I do not think his issue is directly related to his inverter since it has performed well for 4 years, but, in my case my refrigerator would not run on modified sine wave nor would my DW's oxygen concentrator or CPAP.

vito.a · 09-23-2021, 02:32 PM

Our Samsung RF18 refrigerator ran fine with the Trace Xantrex RV3012 modified sine wave inverter.
I later replaced the Trace inverter with a Magnum hybrid MSH3012 pure sine wave inverter, but there is no difference in the refrigerator operation.

mrboyer · 09-23-2021, 04:43 PM

If you add an inverter, it should be as close to batteries as possible and run 120v wire to refrigerator outlet.

Latech · 09-23-2021, 05:34 PM

Quote:

Originally Posted by 96 Wideglide

Which make of fridge do you have?

Seems a lot of members who installed a certain Samsung model, with the factory MSW inverter, don't have issues.

I read that this is because of the way the samsung handles the power. IIRC it converts the AC to DC and runs the compressor off that , and ramps the current up or down to run the compressor, so the modified wave wont matter.
In a regular fridge , with an AC motor the Modified wave inverter causes too much heat and shortens the life , significantly
It is fine with other newer electronics, like TVs and computers because of the way they modify the AC to DC and use it. Plus there are filters and all kinds of goodies to protect the device. Motors dont like modified waves.

paul65k · 09-23-2021, 06:29 PM

Quote:

Originally Posted by Latech

I read that this is because of the way the Samsung handles the power. IIRC it converts the AC to DC and runs the compressor off that , and ramps the current up or down to run the compressor, so the modified wave wont matter.
In a regular fridge , with an AC motor the Modified wave inverter causes too much heat and shortens the life , significantly
It is fine with other newer electronics, like TVs and computers because of the way they modify the AC to DC and use it. Plus there are filters and all kinds of goodies to protect the device. Motors dont like modified waves.

EXACTLY.....modern inverter type compressor refrigerators like Samsung and our GE utilize this type of compressor. We ran our residential refer on our 20-year-old MSW Xantrex Freedom 458 for more than a year without issue until we upgraded our entire electrical system with dual modern inverters and wired it to run everything....including AC units

Dutch Star Don · 09-24-2021, 01:43 AM

When I had my 2005 Diplomat, I eventually changed out the Norcold to the Samsung 18 cubic foot unit. The Samsung units are 110 volt powered, but internally convert that to 12 volts. That's why they played well with an MSW inverter.

With that said, when I installed the new Samsung, I wanted to run it on it's own inverter. I mounted a 600watt Magnum inverter, to the ceiling of the bay, where my Magnum 2000 was installed. I mounted it above the 2000. If you go with a separate inverter, mount it as close as possible to the batteries, as battery cables are expensive. Running romex from the inverter to whatever you want to power up, is cheap and easy.

CountryB · 09-24-2021, 05:16 AM

Quote:

Originally Posted by rffowler55

That is true and why I was saying I do not think his issue is directly related to his inverter since it has performed well for 4 years, but, in my case my refrigerator would not run on modified sine wave nor would my DW's oxygen concentrator or CPAP.

Let me clarify one thing - the refrigerator was replaced by previous owner and is about 4 years old, but the display panel was already broken when I bought the Coach two+ years ago.
The refrigerator works/cools fine - it's just that part of the display (the digital numbers) don't display fully so I cant tell what temperature it is set at and what the actual temp it is (only "half" of the number shows if that makes sense).
Thanks for all the great advise.