Refrigerator : Propane, DC or AC?

[gnykol]

Hey all,

Remodeling my 85' Toyota Dolphin with plans to live in it for an unknown amount of time. Just finishing the frame repair, but looking ahead to electrical with a question for you all:  for long term living , what type of refrigerator would you recommend?

I intend to put a solar panel on the roof with a couple of deep cycle batteries, so I have been leaning towards a fridge that runs on electricity. Recently, I had some folks tell me that my battery would be drained quickly and propane is the way to go.

Looking for an upright fridge with a freezer (no cooler or mini fridge for a weekend worth of beer), as I'll need some room for all my food. Researching right now, and trying to find an option that won't break my bank. What do you think?

[Maineah]

7 hours ago, gnykol said:

Hey all,

Remodeling my 85' Toyota Dolphin with plans to live in it for an unknown amount of time. Just finishing the frame repair, but looking ahead to electrical with a question for you all:  for long term living , what type of refrigerator would you recommend?

I intend to put a solar panel on the roof with a couple of deep cycle batteries, so I have been leaning towards a fridge that runs on electricity. Recently, I had some folks tell me that my battery would be drained quickly and propane is the way to go.

Looking for an upright fridge with a freezer (no cooler or mini fridge for a weekend worth of beer), as I'll need some room for all my food. Researching right now, and trying to find an option that won't break my bank. What do you think?

They make efficient DC  fridges they are pricey ($600 plus) I frankly would stick with propane there is huge amounts of energy in a 20# cylinder far more than a battery can provide and propane does not care if it's dark or raining.

[gnykol]

$600+ , woof. Any brands you like or have heard good things about? 

[linda s]

I like the good condition used ones. Yeah they cost a ton. Keep an eye on craigslist for one or maybe even post your own fridge wanted ad. Winters can destroy a leaky camper and maybe someone has one they are ready to send to the junkyard. Fridge might still be fine. Van campers and some pop top tent campers have the right size.

Linda S

Hey look what I found. He has a few but make sure you test them

https://maine.craigslist.org/rvs/d/lp-gas-fridge/6662114778.html

[neubie]

Someone correct me but the best I could figure one should expect an AH draw from "efficient" dc fridge of at least 3-4AH. May be higher at peak draw. Thats 100AH daily easy. Which translates to 200AH battery bank and 300W solar. Still no real protection against clouds.

Thats more than two panels. There isnt really room for more than 12 panels on the roof of anything but the large americana.

Also, if you do create the solar capacity, then your small dorm fridge ends up competing on price and wins on convenience. Their peak ac draw is 1-2AH. Invertors for this low wattage are under 50 bucks. Fridge is may be 100 and has a compressor, can stay on regardless of leveling.

LP wins on endurance. Loses on price, convenience, maintenance, risk, and everything else.

What are these efficient fridges and how are they popular?

Edited August 13, 2018 by neubie

[Squirrel]

I've only got experience with the Instamatic refrigerator that came with my Dolphin.  But you could spend that $500 (that you would have spent on a new fridge) on enough propane to keep your food cold for quite some time.  If you still have a serviceable 2way or 3way fridge.

[Maineah]

5 hours ago, neubie said:

Someone correct me but the best I could figure one should expect an AH draw from "efficient" dc fridge of at least 3-4AH. May be higher at peak draw. Thats 100AH daily easy. Which translates to 200AH battery bank and 300W solar. Still no real protection against clouds.

Thats more than two panels. There isnt really room for more than 12 panels on the roof of anything but the large americana.

Also, if you do create the solar capacity, then your small dorm fridge ends up competing on price and wins on convenience. Their peak ac draw is 1-2AH. Invertors for this low wattage are under 50 bucks. Fridge is may be 100 and has a compressor, can stay on regardless of leveling.

LP wins on endurance. Loses on price, convenience, maintenance, risk, and everything else.

What are these efficient fridges and how are they popular?

The modern ones power draw is not constant so it's hard to pin a figure on long term consumption they draw X but if you don't open it they are well insulated, enough to cruze along for a good while without running. So say it runs an hour 4 time in 24,12-16 AH. But again you can store tons of energy in a 20# propane tank.

[neubie]

The DC fridge is interesting because of the reduction in propane flame by one too. But I have a hard time believing 12-16AH is enough for a day. They do all seem to draw 4-5AH when cooling.

The only verified figure I have is 1.5A on120v ac for a rm2451 while cooling. Thats 15AH when cooling. Easily takes 8 hours on mine from room temperature. If you get to room temperature for some reason then at no lower than 50% precaution you need 240AH storage to cool down again. Thats not happening with an invertor. People seem to recommend cooling when plugged into shore before unpluggining. And thats a current dometic model.

The fridge situation is less than ideal either way. Perhaps some real world use will change my opinions.

[WME]

Here are some ideas...https://shedheads.net/12v-refrigerator

[MaineErik]

We have two group 27 batteries, 2 100W solar panels, and a 12V marine fridge from Dometic.  Has worked flawlessly for 1.5yrs now.  Camping all over New England.  We also run a Maxx Air fan, range hood fan, pump, LED interior lights, and a small 12V table fan.  On occasion we have the run propane heater too.  A 3rd battery could be added but we've always remained >60% charge with just the two, usually above 75%.

If I did it again I would purchase two 6v batteries and tie them in series - would provide more amps (for similar weight/volume) and they are more robustly built than the dual purpose marine batteries I picked up at the auto store. 

I found the fridge used at a marine store.  The panels cost $100 each, controller was $15 (all HQST), batteries were $90 each.  Wiring was minimal and I did all the work myself.  

Edited August 14, 2018 by MaineErik

[Maineah]

8 hours ago, neubie said:

The DC fridge is interesting because of the reduction in propane flame by one too. But I have a hard time believing 12-16AH is enough for a day. They do all seem to draw 4-5AH when cooling.

The only verified figure I have is 1.5A on120v ac for a rm2451 while cooling. Thats 15AH when cooling. Easily takes 8 hours on mine from room temperature. If you get to room temperature for some reason then at no lower than 50% precaution you need 240AH storage to cool down again. Thats not happening with an invertor. People seem to recommend cooling when plugged into shore before unpluggining. And thats a current dometic model.

The fridge situation is less than ideal either way. Perhaps some real world use will change my opinions.

No there is know way you would want to run an RV fridge on DC unless you are on the road it just sucks up too much current it is resistive heating. The new DC fridges are compressor type with interesting things like swing compressors and real insolation you do however pay for that  dearly. Yes they draw fair current like your home fridge but their runtime is not real long so the overall draw is fairly low didn't your mother ever tell you to "close the fridge door!" so if you don't stand there and look for dinner then they do a pretty good job with overall current consumption. The modern ones cool a lot faster than an RV one what would take a better part of a day with an absorption fridge can be done with a compressor type in a couple hours. If my gas fridge went south I would still buy another one it just so much simpler. More that once I forgot to turn off my fridge and came back a month later to find a cold fridge running on gas.

[neubie]

7 hours ago, MaineErik said:

We have two group 27 batteries, 2 100W solar panels, and a 12V marine fridge from Dometic.  Has worked flawlessly for 1.5yrs now.  Camping all over New England.  We also run a Maxx Air fan, range hood fan, pump, LED interior lights, and a small 12V table fan.  On occasion we have the run propane heater too.  A 3rd battery could be added but we've always remained >60% charge with just the two, usually above 75%.

If I did it again I would purchase two 6v batteries and tie them in series - would provide more amps (for similar weight/volume) and they are more robustly built than the dual purpose marine batteries I picked up at the auto store. 

I found the fridge used at a marine store.  The panels cost $100 each, controller was $15 (all HQST), batteries were $90 each.  Wiring was minimal and I did all the work myself.  

Its a useful data point,  but is missing the fridge size and daily use/content estimation.  200w probably give you 50AH a day from solar.  Presume also the isolator is still in the mix and the alternator is contributing something to the mix when truck is driven.

But even the best numbers and assumptions seem to suggest 3 bad weather/overcast/rainy days in a row will consume all reasonably available juice in the system.  Its better than 1 day you get with 100+ watt that I have, but nowhere near the endurance of an LP fridge.

Have you ever tried to look up amperage when its actively cooling by sticking a  clamp meter somewhere?

[neubie]

1 hour ago, Maineah said:

No there is know way you would want to run an RV fridge on DC unless you are on the road it just sucks up too much current it is resistive heating. The new DC fridges are compressor type with interesting things like swing compressors and real insolation you do however pay for that  dearly. Yes they draw fair current like your home fridge but their runtime is not real long so the overall draw is fairly low didn't your mother ever tell you to "close the fridge door!" so if you don't stand there and look for dinner then they do a pretty good job with overall current consumption. The modern ones cool a lot faster than an RV one what would take a better part of a day with an absorption fridge can be done with a compressor type in a couple hours. If my gas fridge went south I would still buy another one it just so much simpler. More that once I forgot to turn off my fridge and came back a month later to find a cold fridge running on gas.

I guess folks who do go the road of dorm fridges also rely on improved efficiency of a modern compressor system and probably stick a small invertor close to the battery bank.  Not ideal, but far less total cost compared to marine DC.

I am still skeptical of the impressive numbers people are quoting for marine/dc models but if insulation has improved so much that cold losses are minimal then maybe its possible to use such small AH. My home fridge turns on more than a few times a day and it doesnt get any real open/close use. But then again we arent taking house fridge volumes here either.

I am hoping to finally get the entire LP system going this week -- LP, water, drainage remain to be tested in my adventure. Bought a 4 port adapter to avoid having to worry about tank condition/filling issues. Its worth it for testing for leaks/normal operation even if it wont get any real use in normal circumstances.

[Maineah]

A house fridge has a lot of surface area thus they have a greater area to let in heat. The chest type ones are the best but they take up a lot of room. To me this is all a great pluss for good old RV gas fridges. I did a install for a friend with a dorm size modern fridge they were very pleased with it but get this he asked me to give him a hand with the battery he bought for the Sprinter/camper project  it was 1000 AH! Definitely a two man lift glad I convinced him to go with an 80 amp charger to use when ever he could find an outlet. He did not want to add propane tanks and used a diesel heater.

[neubie]

1000AH is a good way to exceed gross weight.

[Maineah]

12 hours ago, neubie said:

1000AH is a good way to exceed gross weight.

Yeah 30# of propane lasts a long long time running a fridge plus it's hard to cook with battery power.

[Derek up North]

1 hour ago, Maineah said:

... it's hard to cook with battery power.

I think the best change for success with current technology is by induction.

[WME]

Maybe the battery had 1000 CCA, a 1000AH battery would weigh over 400 lbs. Think electric forklift.

[Maineah]

5 hours ago, WME said:

Maybe the battery had 1000 CCA, a 1000AH battery would weigh over 400 lbs. Think electric forklift.

Yep that was what it was for but I don't think it was 400# but every bit of 200. I could get it off the ground but I wasn't going anywhere with it. Our 1.5 megawatt generator had 1000 CCA batteries X 4 but I could deal with them.