Residential fridges and INVERTERS! A little help please.

[CountryFit]

Here is another source explaining what startup/surge and LRA mean:

https://support.edgestar.com/hc/en-u...ion-appliance-

[Ivylog]

X2 on the above link that basically says “ LRA - Locked Rotor Amps: The current you can expect under starting conditions when you apply full voltage. It occurs instantly during start up.” and most meters will not accurately measure it...happens to quickly.

[Sweetbriar]

To help finally settle this -

Attached are images of the compressor showing the power details from my Magic Chef 10 cu ft fridge including the lock rotor current of 10 amps.

When I installed the fridge I measured AT the batteries a spike of 110 amps. Battery volts at the time was 12.6VDC which converts to 1360 watts. I measured at the batteries to give me a true number of the total power demand of the configuration to include cable loss, invertor usage, fridge and such. I'm working from memory as the data was collected 3 years ago when I installed the fridge so the numbers might be slightly off.

I used a Simpson HE 95 AC/DC Amps-Clamps meter to measure the amps. Meter response time is listed as 100 msec which is fast enough for most motor surge detection, measurement and display. The meter also has the capability to hold for display surge or peak currents.

The possibility of using a modified sine wave inverter with a Magic Chef 10 cu ft fridge I can't address as I'm using a 2000 watt Xantrex PROWatt which is a pure sign wave invertor.

[Sbrownstein]

Originally Posted by Ivylog

X2 on the above link that basically says “ LRA - Locked Rotor Amps: The current you can expect under starting conditions when you apply full voltage. It occurs instantly during start up.” and most meters will not accurately measure it...happens to quickly.

I think that Magic Chef has already admitted that you will experience LRA amperage IF the reefer is stopped and started up without waiting 3 to 5 minutes. This is a normal situation with refrigeration and A/C compressors when attempting to start the compressor with full pressures. Many systems have "compressor savers" that prevent a restart under these conditions and most modern A/C thermostats also have a restart lockout setting that prevents this issue. In either case, generally, if the compressor cannot start it will attempt that after an over amperage shutdown. remember this will occur during a short power interruption anyway and most units should survive it OK.

Modern, "inverter equipped" BLDC high end reefers (Samsung, Frigidaire, etc) normally avoid this problem since they can sense that the compressor rotor is not moving and will back off and try again later.

[RBlasich]

Originally Posted by Sbrownstein

Samsung refrigerators do not use DC compressors. Just like a whole bunch of Energy Star reefers, Samsung uses a variable frequency inverter built into the unit to power the compressor. That means they convert the AC to DC and then send the DC through the inverter that makes AC to run the compressor at variable speed. Same for Frigidaire and a lot of modern high end reefers. BTW this is the same as "inverter" A/C split air conditioning systems as well.

I have researched my GE GWE19JLSS refrig that I installed in my '06 Holiday Rambler Scepter earlier this year. My information says it has an inverter in the circuit before the "reciprocator" or "Scotch Yoke" type compressor. It sounds like these types of Energy Star units may possibly run suitably on my Magnum 2000 watt MSW inverter and may not require a PSW inverter. Can anyone confirm if this is true?

[FatChance]

When we installed a counter-depth Haier refrigerator (made by GE) in our coach 3 years ago, it worked fine with a MSW inverter. I contacted Haier customer service and they confirmed as well (once I found someone who knew what he was talking about).

[FIRE UP]

Well Gang,
OP here. Well, the Magic Chef 10.1 has been in service now for exactly one year. We've been on several trips with it in place. When transitioning from shore power to inverter power, it has not skipped a beat. I haven't kept track of the freezer section but, so far, the fridge section hovers between about 33 and 38 degrees.
I can tell you that our ice cream is DANG HARD! That KISAE (I think that's the correct spelling) 1000 watt PSW inverter with built in transfer switch is performing flawlessly. As stated earlier in one of my posts, I have a 100 amp continuous duty solenoid that controls the battery power to that inverter. I shut it down when the coach is parked at home or, when we're in a camp spot/RV spot for a few days and will not need battery power for that fridge.

Folks, this was a learning experience for me. I, obviously, don't change fridges daily in our coach so, it was new to me. I found out that this particular fridge and or model, IS NOT to be used in an RV. And, on the same page in the owners manual, it also states, THIS REFRIGERATOR IS NOT TO BE USED WITH AN INVERTER!

Oh well, that's what I get for not doing my homework, reading the owners manual BEFORE I went through all the work to install the fridge, and not doing any real investigation. I think the manual also states that this particular fridge needs somewhere around 5" clearance on each side. Yeah sure. I think I have at most, about 1.5" - 2", maybe. Oh well, if this fridge gives up the ghost on an earlier basis than I would expect, I'll do a bit more diligent research before procuring my next one. But for now, we got COLD food and seriously HARD ice cream, no matter if parked or moving down the road.
Scott

[bobmac]

Scott
I also have a Samsung that I installed in 2013 in my Journey. It has all the same warnings that you have. I use it primarily in the Spring to Fall seasons and have had absolutely no issues. I spoke with a Samsung service dealer and asked why they did not recommend installing them in RVs. His answer was not really straight forward but the bottom line was that they did not want the have to service them inside an RV while under warranty. I am sure you will enjoy it although you will have to learn to drink really cold beer and hard ice cream!

[FIRE UP]

Hey Bob,
Thanks for the words of encouragement. At this point in time, I can't even remember when I installed it but, it's working like a champ along with all the surrounding equipment/components, i.e. assigned inverter and 12V solenoid. Sooner or later I'm gonna install some solar panels so we can do a little extended boon docking. I probably could get away with a couple of days right now but, I'll wait 'till my rig is more adapted for it.
Scott

[US1]

Fire Up, thanks for the update. If you dont mind a little rambling at 1st.....

We just removed our Dometic 8 cu ft absorption fridge today and purchased the same fridge from HD today as you have. Magic Chef 10.1 Cu Ft top freezer @ $349. At that price, nothing to loose. BTW, the box does list it as Energy Star rated.

Good to see a 1000W inverter is working. (the inverter search is what brought me here)

I plan to buy an inverter for use of the fridge only, nothing else. And also just while on the road or overnight at a Walmart. I'm looking to either add a stand alone TS for the fridge, or do as you and get a inverter with a built in TS. I dont want to get into the RVs existing charging system, so no inverter/charger for me....K.I.S.S. I dont want the hassle with moving the fridge plug between inverter and the RV outlet between uses, thus a TS of some sort will be utilized.
I only want to run thru the inverter when not plugged in to SP, and when on SP/Gen be able to turn the inverter off. Not interested in running off the inverter full time. That's just me.
I'm not following your use of the solenoid.

What did you end up doing with your existing vents, left open or closed off? I have approx 1" clearance on both sides and the rear. Top is open to roof vents. At the front, the cabinet frame will fit very close to the fridge sides with null gaps, so basically it will appear as a built in fridge. Does this fridge vent out the back opening at the bottom or out thru the front bottom?

Thanks

[FIRE UP]

Originally Posted by US1

Fire Up, thanks for the update. If you dont mind a little rambling at 1st.....

We just removed our Dometic 8 cu ft absorption fridge today and purchased the same fridge from HD today as you have. Magic Chef 10.1 Cu Ft top freezer @ $349. At that price, nothing to loose. BTW, the box does list it as Energy Star rated.

Good to see a 1000W inverter is working. (the inverter search is what brought me here)

I plan to buy an inverter for use of the fridge only, nothing else. And also just while on the road or overnight at a Walmart. I'm looking to either add a stand alone TS for the fridge, or do as you and get a inverter with a built in TS. I dont want to get into the RVs existing charging system, so no inverter/charger for me....K.I.S.S. I dont want the hassle with moving the fridge plug between inverter and the RV outlet between uses, thus a TS of some sort will be utilized.
I only want to run thru the inverter when not plugged in to SP, and when on SP/Gen be able to turn the inverter off. Not interested in running off the inverter full time. That's just me.
I'm not following your use of the solenoid.

What did you end up doing with your existing vents, left open or closed off? I have approx 1" clearance on both sides and the rear. Top is open to roof vents. At the front, the cabinet frame will fit very close to the fridge sides with null gaps, so basically it will appear as a built in fridge. Does this fridge vent out the back opening at the bottom or out thru the front bottom?

Thanks

Hey US1,
It appears your install and conditions are very close to ours. Side (both) and rear clearances are pretty much the same. As for how this fridge vents, well, like all fridges, there's no vents or slits or any form of an opening on either side. The only opening is at the rear, very lowest part. And that happens to line up exactly with my fridge door on the outside of the coach.

Now, based on the weather, I installed a computer cooling fan at the rear and it's pointed right at the compressor. I manually control it via a tiny toggle switch. The switch is located next to that little fan and it must be accessed by removing the vented door for fridge service, no biggie.

If the weather is warmish, that fan goes on and never stops. If it's pretty cool outside, as in say, the 50's or so, I don't see a need to run it.

Now, as for the solenoid. As you know, I removed the 120VAC from the outlet that was behind our fridge and connected it right to the KIASA inverter. Sooooo, what that means is, that same 120VAC is the power for that fridge when on shore power or gen power. And, I wired from the house batteries, two cables, both 1/0 gauge, right to that KIASA.

Since that particular inverter has the built in transfer switch, the micro second shore power is cut, I think the number is around 1/20,000th of a second, the power demand is transferred to the 12VDC side of things.

The problem I had was, I had NO WAY to disconnect the 12VDC from the inverter since it was direct wired to the house batteries. I needed some way to disconnect it for maintenance or whatever. Sooooo, I purchased a 12V continuous duty 100A solenoid to handle that chore. I wired it right next to my house batteries. Basically, cut the positive cable, installed a copper lug on each end, and put them on that solenoid. Then I got 12V power from under the fridge and ran it to that solenoid to operate it.

I wired a lighted LED switch to operate that solenoid and installed it right next to the remote little panel that operates the fridge. That way, I can tell whether or not that solenoid is ON or OFF. So, that's why the solenoid is in there. Hope this clears things up.
Scott

[veraken]

There are several residential refrigerators that will fit your current opening with only minor mods. I decided on a Frigidaire FFTR1022QB which, once removing the doors, fit thru my door opening. (current model FFET1022UB)

I did a ton of research before replacing my Norcold RV refrigerator and this one came out #1 by far. If you plan to make the conversion, there are some issues.
1. These fridges are not built-ins and will require clearance for air circulation. The Frigidaire needs only an inch on either side, which is probably all you'll have anyway. The back only requires 2" clearance. Other brands wanted far more. Don't be tempted to skip that. They do call for 12" on top, which is impossible for a MH. Instead I installed fans (see #2 below).
2. Operating temperature. Other brands I looked at said their fridge wouldn't operate below 60 or above 90 degrees, and warned against using in a garage. No such restriction on the Frigidaire. Just keep it between 10 and 110 degrees, per the manual.
3. It fit my existing opening with only minor modification.

Installation:
1. I installed a separate 120v outlet controlled by a switch inside the MH so that I could easily turn the unit off when not needed without going outside to pull the plug (some units do not have an on/off switch).
2. I chose not to seal off the existing outside openings. I put a screen on the lower opening and installed 3ea. 12v fans in the upper vent to assure good air circulation. I used the 12v wiring from the old Norcold and put the fans on a thermally controlled line with a separate switch inside my MH.
3. In the back, I anchored the unit by putting 2 lag bolts through the bottom metal rails of the refrigerator into the flooring.
4. Inside, I attached (using 3m 3M Scotch 4910 VHB Tape 2 sided tape) 2 metal brackets to the top of the refrigerator and then screwed these to the wood above the refrigerator. I then trimmed around the perimeter of the fridge with black plastic L channel which I purchased from Display Products online ( Extrusions by Display Products Online). This can be purchased with the tape already attached.