12 volt refrigerator conversion

Topic: 12 volt refrigerator conversion (Read 4827 times) previous topic - next topic

Re: 12 volt refrigerator conversion

Reply #50 – June 01, 2020, 12:14:00 pm

Fred, if you want to do away with the LP cooling and keep the existing refrig then a 12v retrofit choice is probably a good one. It will consume more power, around 120 amps per day. Adding solar will help with the addition load recovery. During an overnight at a Walmart in the mid-winter will use upwards of 2000 watts with heating and lights. That is close to 160 amp hrs, 20% of your battery capacity or more.

If you want to use a 120v version then a new small PSW inverter will be more efficient and use much less power to just be on. This option with a small inverter will use about 12% more battery power.

Re: 12 volt refrigerator conversion

Reply #51 – June 01, 2020, 12:32:49 pm

Fred- I had the 12 volt conversion done in our coach and it worked fine, for a while. After a few months of full timing with it we were having trouble keeping the temps correct as we traveled to different areas, thus different ambient temps. I found that if we turned the control to max cool the compressor worked great but the freezer was not cooling while the refrigerator was down to the 20's. Not good so we scraped it and went with residential ( my posts on this conversion in 2019 at MOT should still be on the forum).

The concept is good and I think the issue with our unit was perhaps a damaged box ( it is a 2001 and third cooling unit in 10 years).
Do what makes your wife happy and then you will be happy. As long as your box is not damaged you should have good results.

Best of luck

Re: 12 volt refrigerator conversion

Reply #52 – June 01, 2020, 02:05:20 pm

Quote from: Roger & Susan in Home2 – June 01, 2020, 12:14:00 pm

If you want to use a 120v version then a new small PSW inverter will be more efficient and use much less power to just be on. This option with a small inverter will use about 12% more battery power.

Roger, PSW inverter?

Re: 12 volt refrigerator conversion

Reply #53 – June 01, 2020, 02:19:45 pm

Pure Sine Wave inverter. Necessary for a residential fridge.

Re: 12 volt refrigerator conversion

Reply #54 – June 01, 2020, 03:07:13 pm

There are no charts showing that a smaller inverter is more efficient under a higher load vs a larger unit at a lower percentage of its capacity.

I asked Victron in Europe for any efficiency charts on their various models and was told that no such charts exist.

Being as they quote an efficiency chart showing a number they obviously have tested their equipment.

Magnum has the only chart I could find with efficiency info. It shows on it 12 volt that it's efficiency drops as the higher percentage loads are applied.

So while it possible that a small PSW inverter can be an advantage their is no charts or tests to verify this.

If there are such charts I would love to see them?

Adding additional wiring for a PSW consumes power by the foot and most would not think to run 4/0 cabling for a small load yet that is the lowest power consumption per foot available.

Better to run a 24/48 volt system for higher efficiency.

But the step down transformer consumes power. No free lunch.

Most efficient for a low to medium load is probably the specifically designed for light intermittent loads would be the Victron 3000 multi pass in my research.

That being said I am guessing their higher efficiency is at the projected loads.

No way to verify this.

My non engineering test IF I had a small PSW inverter already installed would be to turn it on and heat gun the inverter and the wiring. If it warms up it's consuming power.

I bet the bigger multipass shows very little heating at a lighter load like a residential refer.

I personally wish that a dedicated smaller inverter with its extra wiring being optimized for draws would save power.

Possible it does help. Just no info.

Please show how this helps? The idle draw current may help a bit. But if the efficiency is lower maybe be more offset?

Re: 12 volt refrigerator conversion

Reply #55 – June 01, 2020, 03:29:00 pm

Quote from: Caflashbob – June 01, 2020, 03:07:13 pm

......So while it possible that a small PSW inverter can be an advantage their is no charts or tests to verify this.

If there are such charts I would love to see them?......

I agree with you Bob, no easy answer. For someone desiring to know, the following video gives them a path.
https://youtu.be/KvXzuYqSIyE

Previously I have watched Will Prowse YouTube video of portable electric generators, with him testing their converter efficiency. I'll post one if I can find again.

It may have been the following.
https://youtu.be/xjl3s1CdYII

Re: 12 volt refrigerator conversion

Reply #56 – June 01, 2020, 04:02:30 pm

Idle current draw is the big difference between the large vs small inverter options. Talking in round numbers, if my magnum 2812 draws 5 amps just to keep it turned on, and my dedicated fridge inverter draws 1 amp, that's 4 amps that I'm saving while only running the fridge inverter....which is the case 90% of my day & night while dry camping. It made a big difference before adding solar, and is still significant after solar.

Re: 12 volt refrigerator conversion

Reply #57 – June 01, 2020, 04:57:20 pm

I just installed my Edecoa 1500 watt pure sine wave inverter. I ordered it direct from China for about $125 delivered. It is the same as the model on Amazon with the exception of no USB ports. Nice remote, dead silent, runs microwave over twice as fast and will start a compressor. Note that the YouTube review and load test does not have the later panel with the current draw and display that mine does. Glad to post photos. No load is about .65 amps. Review shows the ocilloscope waveform. I have a ocilloscope adapter for my Galaxy Tab S, S2 ordered and will post the pattern when it arrives. I removed the power hog Taytronics inverter. The Edecoa weighs about 10 percent of the old one and starts my compressor where the Taytronics would not.
https://www.amazon.com/EDECOA-Inverter-Converter-Remote-Controller/dp/B0823K6MLQ/ref=sr_1_1?dchild=1&keywords=edecoa+1500+watt+sine+wave&qid=1591043879&sr=8-1

Here is the review and load test:
https://www.youtube.com/watch?v=-2fb49YWzMo&t=340s

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: 12 volt refrigerator conversion

Reply #58 – June 01, 2020, 07:32:08 pm

My Victron Phoenix inverter is 91% efficient and uses 7 watts to be on. That is just over 0.5 amps at 12.6v.
My Victron Multiplus inverter/charger is 93% efficient and uses 15 watts to be on.

Easy to find the specs if you want to. The discussion in post #54 is the poster's often repeated bias.

So if your refrigerator with a 120v conversion uses an average of 55 watts per hour then power from the battery through the Phoenix inverter will be 55/0.91 + 7 = or an average of 67 watts per hour. If the 12v version also uses an average of 55 watts per hour the 120v solution will use 22% more power than the 12v solution. Some times your refrigerator will use very little power. When it is running it will use about twice the average.

The only way to know is to add monitoring to measure the power used going into the 12v version or going into the inverter powering the 120v version. How you use the refrigerator, the temperatures you set it at, how often you open and close the door, how well tour door seals work, how warm it is in your coach, which side your refrigerator is on relative to the dominant sun and much more. It is complex. Using a smaller inverter, installed properly will use a significant amount less power over the day just to be oncompared to a bigger one. If you are plugged in most of the time it probably doesn't matter.

Re: 12 volt refrigerator conversion

Reply #59 – June 01, 2020, 07:40:02 pm

The only advantage of a 24 or 48 volt system is the reduction in wire size required. Doesn't really make sense on a 36 to 40 ft coach. Unless you're building from scratch. And then as you said you have to have 24 to 12 volt converters, which themselves use power.

Re: 12 volt refrigerator conversion

Reply #60 – June 01, 2020, 07:53:29 pm

Ok I will bite. At what exact output power was the quoted efficiency?

All other inverters have a roll off at higher loads. Victron denies having the info. I asked.

24 volt stuff has much higher efficiency that 12 volt. 48 volt better yet.

Show me the chart showing the efficiency please?

I will post the magnum chart.

Show me a chart.

Re: 12 volt refrigerator conversion

Reply #61 – June 01, 2020, 08:03:45 pm

Bdale here is your magnum info.

Re: 12 volt refrigerator conversion

Reply #62 – June 01, 2020, 08:07:53 pm

Looks like the topic has ceased on the 12 volt refrigerator conversion and is now about Pure Sine Wave inverter and efficiency. Should probably be split at reply 50 to new topic if discussion will get more technical. Thoughts?

Edit
Ted, thanks for completing the loop for the conversion and resulting decision to residential fridge.

Re: 12 volt refrigerator conversion

Reply #63 – June 01, 2020, 08:15:30 pm

The Magnum has the ability to be set to the amount of load that it takes to turn it on.

It can also be set to turn off totally then start searching after a preset adjustable interval. Search mode is 8 watts.

Idle current is 30 watts. 30 divided by 12 volts is less than 3 amps.

That's why your ms2812 has the ability to turn itself off then come back on to see if it's needed.

Plus the turn on load is adjustable. In other words it can stay off until the refers call for power versus radio face plates or other tiny loads.

If you have a Samsung refer my understanding is that it is never "off" compressor varies speed instead. So no idle load.

Victron went to a round transformer versus dual "d" shaped much physically heavier designs designs optimized for comtinoius heavy loads before derating.

Victron s tech paper mentions they changed their design to increase their efficiency as their primary market used their inverters for short times and medium loads in fairly cool weather(boats?)

They used to have dual transformers like the rest of the industry. 52-55 pound units versus 40...

Re: 12 volt refrigerator conversion

Reply #64 – June 01, 2020, 09:05:21 pm

Bob what do you have to say about my Xantrex SW 3012 @77 l;bs? Does the weight make it better?

http://www.xantrex.com/documents/Inverter-Chargers/Freedom-SW-NewGen/DS2020416_Freedom%20SW%2012V.pdf

Re: 12 volt refrigerator conversion

Reply #65 – June 01, 2020, 10:11:57 pm

Heavy duty hybrid design. Obviously designed for continuous heavy loads. 150 amp charger. Will charge deeply discharged batteries.

Yes I think the heavier unit will have bigger transformers with increased ability to output heavier loads before derating.

I hope no one misunderstands me. For specific uses the Victron is a finely tuned piece of equipment. Intentionally designed for max efficiency at medium loads

If you were drawing heavy loads and/or hot areas all the time other units may be better for those uses.

Your xantrex can probably run roof air(s) no problem for long runs.

Made for it. At least it's capable of it.

Re: 12 volt refrigerator conversion

Reply #66 – June 02, 2020, 01:21:06 am

I run my air off my victron.. with solar it does great.. have also ran both airs but it doesnt like it. When running the air it is pulling a load.. I typically do not worry about what is on or off when I am in the motorhome.. the victron holds its own.

Re: 12 volt refrigerator conversion

Reply #67 – June 02, 2020, 04:32:22 am

Quote from: DavidS – June 02, 2020, 01:21:06 am

I run my air off my victron.. with solar it does great.. have also ran both airs but it doesnt like it. When running the air it is pulling a load.. I typically do not worry about what is on or off when I am in the motorhome.. the victron holds its own.

David the Victron, with your 1200 amp, 15,000 kwh of lithium gives you an amazing system. This has to be the largest lithium bank on this forum. Congrats on not having to worry about what is on or off.

Re: 12 volt refrigerator conversion

Reply #68 – June 02, 2020, 10:10:53 am

I toocan run my front air off the victron and solar without issues for around 6 hours.

Re: 12 volt refrigerator conversion

Reply #69 – June 02, 2020, 12:12:02 pm

On my 95 U240, i have 2 8Ds for the coach, 2 optimu red tops for starting. I do very little dry camping, maybe overnight at walmart. My orig. RM4804 Dometic Frig. works on both ac and propane. Over night on AC in the am frig. will be 28-30 deg. During the day on the road running on propane it does not do as well. So I bought a small inverter and put it in the back of the frig. compartment. The 12v supply is already at the frig. and now the frig will run on 120 vac all the time. At home I have shore power, on the road the 160amp engine alternator charges all batteries, and in the RV park I have shore power. If I over night in a walmart parking lot, how will my 2 8Ds do? If I have to, the onan will handle the job. What do I need to look out for? What do ya'll think about the idea?

Pat,

Re: 12 volt refrigerator conversion

Reply #70 – June 02, 2020, 12:47:31 pm

Pat,

Particularly when parked the refrigerator should work just fine on propane.

Have you done the "burner area tune-up"?

If so and it still doesn't work properly, check propane pressure or just replace the propane regulator if old. They are under $25.

Re: 12 volt refrigerator conversion

Reply #71 – June 02, 2020, 12:48:14 pm

Fred,
I installed a Vitrifrigo 12V/120VAC marine refrigerator so I can't speak to the conversion of your OEM unit. It uses the Danfoss compressor like the conversion however, and in our 99' U270, there was adequate 10 gauge 12V wiring already present. The 12V positive feed is connected to a 30 AMP breaker in the storage compartment behind the white fiberglass cover. It was unused in our coach before the change out as we did not have an OEM 3 way fridge.
Don

Quote from: ViewRVs – May 31, 2020, 12:44:58 pm

I wanted to ask three follow-up questions regarding the 12v refrigerator conversion.

1) Did the shop have to take the fridge out of the cabinet and out through the front door to do the conversion?
2) Is there already a usable 12v power in the fridge compartment suitable for running the fridge to run on 12v? (We have a 1996 U320)
3) Has anyone taken their coach to JC Refrigeration and had them do the work at the factory?

We are seriously looking at the 12v conversion since our fridge has stopped working. The goal is to switch the fridge to the 12v compressor model, remove the large (and heavy) unnecessary LP tank, add very small LP tank to just run the cook top (the only remaining LP appliance in the U320), and potentially add battery capacity to the 2 batteries that we have now for extended boondocking.

Re: 12 volt refrigerator conversion

Reply #72 – June 02, 2020, 02:07:01 pm

OY!!!

Y'all exhaust me on your inverter/power conversations. Particularly when the thread was resurrected with questions specifically about the fridge conversion at JC Refrigeration.

Quote from: ViewRVs – May 31, 2020, 12:44:58 pm

I wanted to ask three follow-up questions regarding the 12v refrigerator conversion.

1) Did the shop have to take the fridge out of the cabinet and out through the front door to do the conversion?
2) Is there already a usable 12v power in the fridge compartment suitable for running the fridge to run on 12v? (We have a 1996 U320)
3) Has anyone taken their coach to JC Refrigeration and had them do the work at the factory?

We are seriously looking at the 12v conversion since our fridge has stopped working. The goal is to switch the fridge to the 12v compressor model, remove the large (and heavy) unnecessary LP tank, add very small LP tank to just run the cook top (the only remaining LP appliance in the U320), and potentially add battery capacity to the 2 batteries that we have now for extended boondocking.

We can help you with your questions!!

1. Yes, JC Refrigereation will take the fridge out of the kitchen, and lay it down on the living room floor. They will take out the old cooling unit, and replace it with whatever you choose before reinstalling the fridge back in the fridge compartment. The fridge itself will never leave the coach.
2. Yes, you have a 12v connection for the fridge already installed.
3. Yes, we had JC Refrigeration do the work for us at their factory....twice. See below.

We are one of the only, if not the only customers of JC Refrigeration that have used BOTH his 120 volt conversion AND his 12v conversion. Like you, our fridge cooling unit died a little over 2 years ago. We had all the choices before us, and knew we wanted to keep the original fridge with the wood paneling. We chose to be one of the very first customers with the 120 volt conversion. That was in installed May 2018. It worked great until about April 2019, when we started having the same problems that Ted & Karen expressed above. We called JR at JC Refrigeration, and he said he would make it right and gave us the option of sending us a new conversion, or we could visit him back at the factory. We drove back to Shipshewana, Indiana, in May 2019, and this time, we had him install a 12v conversion in place of the 120 volt conversion at our request. That worked fine until the fans that JC Refrigeration installed in our fridge went kaput in March 2020. JR mailed us another fridge fan for free, and we just can't seem to get the temps low enough. We are fulltimers, and travel to areas with differing temps and humidity. It works great when the humidity is lower and temps outside aren't above 75.

So to recap our experience, the 120 volt lasted about 11 months, and the 12v worked great for about 10 months, and unfortunately, we are still futzing with it even today.

JR has been fantastic to work with. He has been immediately willing to help us when we alert him to a problem with our fridge. Stand up guy with great customer service. If we were to do this ALLLLL over again, we would choose to have JR replace our original cooling unit with his rebuilt cooling unit, still using propane, and skipping the new technology of 120 volt and 12v conversions. Everyone that has had JR install a rebuilt cooling unit has had outstanding results, and sadly, everyone we know that has gone with his new 12v or 120 volt conversions have had the same issues. I was THRILLED to be the guinea pig for the electric conversions since that would eliminate my fridge fire phobia. HOWEVER, at this point, knowing what I know, I would have JC Refrigeration install a rebuilt cooling unit and continue using propane.

Re: 12 volt refrigerator conversion

Reply #73 – June 02, 2020, 02:09:41 pm

Several off topic posts deleted.

Please keep posts to the original topic.

Thanks.

Brett/moderator

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