Residential fridges and INVERTERS! A little help please.

[Ivylog]

Depends on where the condenser coils are. Mine are on the bottom but I did not close off the back vent/door or the top vent BUT we winter in SE Fla. If I was going to be in cold weather I’d probably tape the vents closed on the back vent/door and not worry about the top vent.
If the coils are on the back I’d definitely leave the vents open and go with little or no side and top clearance...all the hot air goes out the top.

[tommar]

Remember, a compressor-driven residential fridge cycles! It's not running all the time, not even close, so puts out much less heat.

[Spk64]

Originally Posted by jcussen

Just a question for those that have replaced their absorption fridges with residential ones, and have blocked and insulated all the vents. In a 2000 s/f house, lots of room to dissipate the heat, but in a 300 s/f motorhome, do you notice the extra heat the fridge produces? I guess in the winter no problems, but here in south texas, the ac's can barely keep up with a well ventilated {with blowers] absorption fridge.

I have not noticed any extra heat load. The coils on our Frigidaire are on the sides and a small gap is on side along with vents top and bottom of refrigerator.

[FIRE UP]

Yahooooooo
Got my Mini Split 33,000 BTU Garage A/C installed yesterday. Took about 4-5 hours for the total install, and that included a dip or two in the pool 'cause we (a buddy and myself) were sweating up a storm due to our present Lake Havasu weather/Monsoon conditions in heat and humidity.

So, now that it's a chilling 80-82 degrees constant in the RV garage, I can now resume *RV* projects.

1. Resume where I left off on the fridge/inverter issue.
2. Remove my basement A/C and change badly needed parts/bushings/bearings/fan etc.
3. Replace (1) broken Nylon slam latch on one of my compartment doors
4. Check and/or, re-sew edges on awnings due to fraying.
5. Check reason why main awning won't *Auto-retract*

Yep, got plenty to do now, in my new, NICER working conditions.

Now, as for procuring a separate inverter for the fridge. Many of you suggested a 1000 watt one will do the trick. Others have stated a 500 or 600 watt one will work. I'm not one for buying something smaller just because it "might work" in our situation. But, I also understand that, the larger the inverter, the more *wasted energy* it has/uses when in the idle state. Now, I'm not too worried about the *wasted idle state stuff* since we do hook-up camping about 98% of the time. But, why buy bigger than you need? And, this potential inverter will ONLY power the fridge, NOTHING ELSE.

The answer I received when I asked a question on Home Depot's website pertaining to the start up amps and, running amps was this:

The unit is 140W and 1.4 Running Amps.

Well, I'm not the sharpest tool in the shed when it comes to electricity. I know just enough to get myself in trouble. To me, that answer is not a complete answer. Since I cannot find any form of data sheet pertaining to that particular Magic Chef 10.1 cu. ft. residential fridge, I still need to find out what the start up amps are. Above it states: "The unit is 140W".....
What EXACTLY does that mean?

Scott

[tripntx]

I used this Plug-in Kilowatt to determine our 10.1 Magic Chief uses approximately 5.5 amps starting up.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[richard5933]

Originally Posted by tripntx

I used this Plug-in Kilowatt to determine our 10.1 Magic Chief uses approximately 5.5 amps starting up.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

That at 120vac, right? That would mean it's pulling over 50 amps on startup from the batteries through the inverter.

[jacwjames]

I installed a Samsung RF 18 that will work on my MSW inverter but I am considering installing a separate inverter to improve efficiency.

A senior member of another forum provided me with info that seems logical.
Install this inverter
https://www.ebay.com/itm/Aims-1000-W...53.m1438.l2649
near the batter bank and plug it into the engine heat circuit. This way it can be turned and off easily. I could install this inverter in the small space below my washer or behind the TV.

This inverter can also augment charging of the batteries when plugged in. Then just run a decent size extension cord to the fridge compartment.


When not in use just turn off the engine heat switch to prevent charging and the inverter to turn off fridge.

[tripntx]

Originally Posted by richard5933

That at 120vac, right? That would mean it's pulling over 50 amps on startup from the batteries through the inverter.

Yes, the 5.5 amps are measured on the 120vac line-out from Power Dynamics 1,000 watt Pure Sine Wave inverter.

[paul65k]

Originally Posted by FIRE UP

Yahooooooo
Got my Mini Split 33,000 BTU Garage A/C installed yesterday. Took about 4-5 hours for the total install, and that included a dip or two in the pool 'cause we (a buddy and myself) were sweating up a storm due to our present Lake Havasu weather/Monsoon conditions in heat and humidity.

So, now that it's a chilling 80-82 degrees constant in the RV garage, I can now resume *RV* projects.

Sounds glorious!!

I'll have to get a little more info on what and how much!!

Most of the people I've seen doing the upgrade have been able to run the larger 18CF fridges on 800W inverters as most I have see (Victron especially) can spike to 2X the rated capacity for the time needed to get the compressor started, so Im thinking 600W would be fine if you want to dedicate for only the refrigerator.....the standby power is really minimul on either of those and the price difference is also pretty close

If you haven't added a battery monitor yet (a real one) then the Victron SmartShunt is probably one of the first things you'll want to add, then a Victron inverter would make sense......both can be measured via Bluetooth on your smartphone......I'd be happy to give you a quick overview on how this all works on my rig when/if we get together here in Havasu!

Cheers!

[veraken]

Originally Posted by jcussen

Just a question for those that have replaced their absorption fridges with residential ones, and have blocked and insulated all the vents. In a 2000 s/f house, lots of room to dissipate the heat, but in a 300 s/f motorhome, do you notice the extra heat the fridge produces? I guess in the winter no problems, but here in south texas, the ac's can barely keep up with a well ventilated {with blowers] absorption fridge.

This is what I did

1. These fridges are not designed to be built-ins and will require clearance for air circulation .

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 these fans on a separate switch that is thermally controlled.

3. I installed a separate 120v outlet on a switch 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).

[Sweetbriar]

Originally Posted by FIRE UP

,,,
The unit is 140W and 1.4 Running Amps.

Well, I'm not the sharpest tool in the shed when it comes to electricity. I know just enough to get myself in trouble. To me, that answer is not a complete answer. Since I cannot find any form of data sheet pertaining to that particular Magic Chef 10.1 cu. ft. residential fridge, I still need to find out what the start up amps are. Above it states: "The unit is 140W".....
What EXACTLY does that mean?

Scott

Watts are a measurement of work or power. For electrical purposes from watts you can determine how many amps you'll need at a specific voltage for the device to do it's designed work. Using your 140 watt number and 120VAC you'll need 1.16 amps (Watts/Volts=Amps). At 115VAC the amps increase to its 1.21 (volts drop, amps increase). If the volts were 12.0VDC you will need 11.6 amps from the batteries (plus what the inverter consumes and a few percent for line loss).

On my 10 cu ft Magic Chef (2017 model HVDR1040B) I measured a start surge at the batteries of about 100 amps for about 2 seconds. At 12.6VDC (batteries just off the charger) the wattage was 1260 watts. Inverting to 120VAC 1260 watts will need 10.5 amps. You might see something slightly different depending on the model fridge you have which could have a different compressor or different refrigerant. Once the surge had passed the numbers drop to about what the label plate has.

[Old Scout]

...you also need to worry about ice makers and defrost cycles in some models of fridge--need more amps. Seems to me that once you get above 1000watts, a new or existing whole-house inverter of 2000watts would be better....rewiring the fridge to inverter circuit is fairly easy at the main breaker boxes--effort varies by RV of course....

[Journey cat]

Originally Posted by FIRE UP

Yahooooooo

1. Resume where I left off on the fridge/inverter issue.
2. Remove my basement A/C and change badly needed parts/bushings/bearings/fan etc.
3. Replace (1) broken Nylon slam latch on one of my compartment doors
4. Check and/or, re-sew edges on awnings due to fraying.
5. Check reason why main awning won't *Auto-retract*


Scott

Ill be watching ! And will follow your lead ,
ON #2
I have already purchased the blower wheel for $59 on E Bay .
And have wondered if insulation or sound deadener can be added ,
Ill just try to make it better , but ill know everything is up to date .
Best of luck on the project !

[bobmac]

I installed a Samsung RF-197 in 2014 - the predecessor of the RF-18. It is powered by my Dimensions MSW inverter. Since Samsung fridges of this vintage - and possibly still - use DC voltage converted from AC to power the compressor, it runs well with the MSW input as it converts it to DC. I have had absolutely no issues with the fridge. There is absolutely no need for pure sine wave power due to the conversion to DC. My fridge does not use digital displays.