Fridge not working; 12V replacement?

[HikeSticks]

Hi Folks,
I bought my '72 Trillium last summer and have put thousands of miles on it already. However, the fridge didn't work when I bought it. (I was told about it) This hasn't been a major concern. I have used one of the tips I noticed here and put 2-2litre frozen pop (soda) bottles in the lower compartment. It keeps the contents cold for 2-3 days and and I have drinking water when it thaws. I'm fairly certain the fridge isn't original to the trailer because it has a wood frame around the outer edges to fill the gaps; the fridge is smaller than the hole. I'm thinking about a replacement. I never use serviced sites but I would like to use a fridge in 12V mode. I have a stand alone 12V cooler but don't like to loose the extra space.
My question is; What are the battery requirements for maintaining a 12V fridge? I can recharge the batteries while driving and/or start the car for a while each day for that purpose.Would one good Group 27 battery do? I am also replacing my propane regulator with a double and will carry 2-20lb tanks so propane should be practical if the operation isn't too problematic. (I hear the fridge has to be quite level and that isn't always the case when I stop for the night.)
I know nothing about these fridges so any advice will be appreciated.
Thanks,
Barrie

[Randy Magee]

My Dometic fridge will pull down a 12V battery very quickly... while towing and using 12V power the battery will barely maintain it's charge and the 12V operation of the fridge while towing will only maintain the temperature inside the fridge. If there is no 120V current available, I operate the fridge with propane as the battery will be drained in a matter of hours while operating with 12V.

[HikeSticks]

Thanks Randy. I guess I'm looking at running propane then if I plan to use the fridge for anything other than an ice box. I got along fairly well using the frozen pop bottles but I loose a third of the space.
Cheers,
Barrie

[Tom U]

Barry,

What Randy said meshes with our experience. The draw in 12v is huge, battery barely maintains charge while towing and goes down FAST when fridge is drawing w/o charging going on. We don't even use the 12V setting any more. I forgot to switch over to propane one night and had a dead battery in the morning. Now when on the road we use frozen food or ice as coolant.

We use Propane when we don't have 110v. The fridge stays very cold on very little propane.

If I had to have a one way fridge it would be propane.

[HikeSticks]

Thanks Tom,
I was surprised how little propane the furnace burns on my way to and from Florida in November. It sounds as though the fridge is propane friendly too. I have also seen manufacturers statements that being level is important too? I often don't bother with leveling if I'm just parking for the night. I just put my pillow on the 'up hill' side... A new fridge is fairly expensive so I'll have to decide if it's worth switching over from using the old one as an ice box.
Cheers,
Barrie

[Tom U]

Originally Posted by Barrie Bochoff

It sounds as though the fridge is propane friendly too. I have also seen manufacturers statements that being level is important too?
Barrie

Barrie,

Yes, they use very little propane. I've gone close to three weeks on a 20lb. cylinder using the heater, stove and fridge every day: fridge 24/7, heater every morning and two meals a day on the stove.

Level is important. You don't have to be 100% laser level, though. "Sort of level" will work. The way they are designed (many threads on this) requires that the coolant be heated and able to circulate. Out of level prevents this from happening so, no cooling. There is a margin of tilt.

I bought an inexpensive bubble level that I keep in the bottom of the fridge. This is more accurate than the levels on the outside of the trailer. I've found that as long as I have a half bubble in the center I am cool .

[HikeSticks]

Thanks Tom. I'm sure I can get within half a bubble easily enough.
With the price of gas this year I plan to spend more time parked and less time driving so a working fridge is becoming more attractive.
Cheers,
Barrie

[cpaharley2008]

The 2 way 12v/120v refers do not use a lot of battery juice. They pull around 2 amp per hour while running and they may only run 50% time so with a 100 a/h group 27 you may last maybe 2 days. The 3way 12v/120v/lp refers use a lot more 12v amp hours. But on propane they pull less than one amp so that is the way to go, unless you do not or can not keep the trailer level. If you have other propane appliances that is the way to go.

[HikeSticks]

Hi Jim,
I'm a bit confused. Do you know what the difference in the 12V technology is between the 2 way and the 3 way fridges? Why would the 2 way use fewer Ah than the 3 way to produce the same cooling? I have a 2 burner range and a propane furnace but if a 2 way, 12v/120v, fridge can work for 2 days without recharging the battery... gosh. I'll see if I can find comparable spec sheets to try to understand.
Barrie

[Matt in SV]

My 3 way LP/12v/120v (ammonia condenser tech) doesn't use any electricity when running on propane. But it's not very efficient on electricity. At 120v that inefficiency doesn't matter much.

I think Jim is talking about a compressor fridges that runs only on electric, 12/120v?

Regards,

Matt

[Stoney]

We have a novacool 3100 3.1cubic ft it draws 2.4 amp per hour but keep in mind it doesn't run all the time we have a dual 6volt set of batteries with solar but I'm sure that we could go for a weekend easy enough with out charging or plugging in the fridge is 12v only and is so efficient that we keep it set only on level 2 , cheers mike

[HikeSticks]

I understand now, there are 2 different technologies at work; absorption cycle vs compressor. I appreciate the feedback. I asked because I didn't know.
I'm installing a dual regulator with 2 x 20 lb tanks so I would have lots of propane. I also like the idea of the 12v/120v 2 way if it's really that much more efficient for use with a battery. I never use a serviced site so the 120v is a moot point. ( I find the unserviced sites tend to be larger and less crowded that serviced sites.)
Now I just have to see if there is any price differences to throw into the mix.
Thanks all.
Cheers,
Barrie

[cpaharley2008]

Originally Posted by Matt in SV

My 3 way LP/12v/120v (ammonia condenser tech) doesn't use any electricity when running on propane. But it's not very efficient on electricity. At 120v that inefficiency doesn't matter much.

I think Jim is talking about a compressor fridges that runs only on electric, 12/120v?

Regards,

Matt

Yes I was But, I think the propane still draws a little current for the circuitry, albeit miniscule.

[cpaharley2008]

Originally Posted by Barrie Bochoff

I understand now, there are 2 different technologies at work; absorption cycle vs compressor. I appreciate the feedback. I asked because I didn't know.
I'm installing a dual regulator with 2 x 20 lb tanks so I would have lots of propane. I also like the idea of the 12v/120v 2 way if it's really that much more efficient for use with a battery. I never use a serviced site so the 120v is a moot point. ( I find the unserviced sites tend to be larger and less crowded that serviced sites.)
Now I just have to see if there is any price differences to throw into the mix.
Thanks all.
Cheers,
Barrie

Like I said earlier, since you already have propane then I feel it is the way to go, unless the trailer is not set up for propane refer with vents and tubing. Otherwise 12/12v is best for non vented setups.

[Mark Shaffer]

The small 3-way refrigerators do not use any voltage on propane, it is just a matter of turning the frig. manually over to propane and hitting the ignitor. Now the larger refrigerators with the automatic switch do require 12 volt for the circuitry that senses the loss of power and automatically switchs the frig from 120 to propane. The 12 volt heating element in the smaller 3-way refrigerators is pretty much a dead short on your 12 volt system. Not only will they drain a fully charged deep cycle battery on your camper, but if the plug in is connected to your tow vehicle, it can pull the battery dead on it also if sitting for an extended period of time. Basically the 12 volt option is pretty much useless except for emergency use while going to buy more propane. IMO

[cpaharley2008]

I think the 12v option is for enoute, being towed and being charged by the tv, since it is frowned upon for propane use while being towed.

[Tom U]

Originally Posted by cpaharley2008

Yes I was But, I think the propane still draws a little current for the circuitry, albeit miniscule.

Jim, our 3-way was only hooked up as a two way, propane and 120v. There was no connection to the battery and it worked well in both modes. With no 120V service and no connection to the 12V system it really cooled well on propane. So, IMHO, no draw.

I hooked it up to the 12v system just 'cause and now I never use it in 12v mode except, occasionally, as stated above while towing.

I considered swapping it for a compressor fridge but decided not to - we do a lot of boondocking and really like the propane option, don't have to risk a dead battery due to any charging issues - generator malfunction or cloudy days for the solar. The three way is a little more expensive but is a real CYA system.

[Evergreen]

I just pulled our old 3-way out and installed an Engel 12v only fridge in our 13' Scamp. Nice thing was the depth of the new fridge was perfect, I had to make the front hole a bit smaller though. The upside is this fridge will draw only 3 amps max. I am told if it is hot out it will run half the time. So just over 30 amps per day. I have 2 40watt solar panels, 110 charger and will have tow vehicle charging. I am installing 2 6v golf cart batteries so if they are fully charged, even without any sun or other charging I should be able to go about 3 days. The new fridge is also much larger inside than the old 3-way. Nice thing with this system is that I can go away for a couple of days and leave the fridge on (or longer if sunny or plugged in), I probably would not feel very comfortable leaving a propane fridge going. Oh, and a new 3-way will not fit the older Scamps without increasing the depth of the cabinet.

[HikeSticks]

Thanks Evergreen. I'd appreciate more information please; model, price, vendor... I Googled 'Engel 12v' and just got coolers. 30 Ah a day sounds great.
Barrie

[Evergreen]

Hi Barrie, here it is on Amazon Amazon.com: Engel SB70F Built-in DC Fridge Freezer: Electronics. I got it from another vendor, can't remember which now but it was $650 including shipping. Not cheap but once you stray from 110v nothing is. I chose this fridge for a couple of reasons, I am a cruising sailor and live on 12v full time so I am used to it. I have also met a lot of cruisers that use the chest style Engels and all I have heard is how great they are and how little power they draw. It also makes things simple when we connect the tow vehicle, just plug in and the fridge is powered, don't have to remember to switch the propane off (learned this sailing, make things as simple day to day as possible).The chest and the SB70 use the same compressor which is very efficient so I am hoping that it will prove to be a good decision. This unit does not need the outside vent panel so I removed that from our camper and fiberglassed the hole (we are painting once the fiberglass work is done). I'll let the board know when we fully test it this summer in our 3 month road trip . If you have any specific questions about our setup just let me know. I would not though try to use a single deep cycle battery, which is why I am going to 2 6v golf cart batteries.