Outline · [ Standard ] · Linear+ Fridge power question

[Dorado]

Just a quick question on my fridge.
I was re-wiring the 7-pin plug on my truck and saw that the power supply wires are 10 or 12 gauge. I got to thinking about the fridge on my camper.
My 1997 Lance 880 came with a Dometic 3-way Refrigerator. Gas, AC, and DC. It'll run off of the truck as well. I know that the power comes through the 7-pin trailer light plug on my truck. The harness coming off of my camper has 8 gauge wires for truck power I was wondering if my truck needs 8 gauge wire as well.
I want to get things right while I have everything torn apart.
Do I need 8 gauge wire for the power supply on my truck or will the 10 or 12 gauge wire be enough?

[towpro]

Just a quick question on my fridge.
I was re-wiring the 7-pin plug on my truck and saw that the power supply wires are 10 or 12 gauge. I got to thinking about the fridge on my camper.
My 1997 Lance 880 came with a Dometic 3-way Refrigerator. Gas, AC, and DC. It'll run off of the truck as well. I know that the power comes through the 7-pin trailer light plug on my truck. The harness coming off of my camper has 8 gauge wires for truck power I was wondering if my truck needs 8 gauge wire as well.
I want to get things right while I have everything torn apart.
Do I need 8 gauge wire for the power supply on my truck or will the 10 or 12 gauge wire be enough?

I think I read that to run those refrigerators on 12v, its requires around 10a.

a wire size calculator found on internet just showed me that for a 12V 10A load, you need 9agw for a 5% lose in 25'.
figure 6' to come out engine compartment back to under back of cab, than 8' length down bed, than 10' wip to come back to camper = 25'.

I know my factory wires on my Ram might do 4-6 amps depending on how much charge battery has.
I would rather put some charge back in camper batteries from truck than run 12v refrigerator.

I run my refrigerator on propane while underway. Many of us do. But I am not looking to start an argument on the perceived safety issues of running refrigerator on propane while moving.

But this argument does not hold if your using one of those new 12V/120V compressor refrigerators.
l

[SidecarFlip]

Cool it down on shore power (110V) before you leave home, load it with pre cooled and frozen food and turn it off while on the road (if you are adverse to running propane while underway (I'm not), however, under federal highway law, if you pass through any tunnel, the propane must be shut off. I don't do tunnels so no worry with me.

Keep in mind that unless it's a compressor fridge, you cannot load it with room temperature food and expect to cool the food down, won't happen. Just shore power it at home,for a day or so and load it with cold food and run it on propane or shut it off until you get to your camp and start it up (on propane or 110V or 12 volts (whatever you prefer.

A cold fridge with cold / frozen food will retain the temperature for many hours so long as you keep the door closed.

[Dorado]

Oh I was fully planning on cooling it down before hand and that I'd put in cold food. But I know that some places don't want you running propane while driving. And there's no point in using up the gas when the truck is already running. I'd rather save the propane, and utilize the truck.
Still. I want to have everything hooked up properly. I'm going to try to wire it up today. Depends if I can fix my brother's car or not. As well as finish my brother's project on my daily driver truck. He decided to surprise me by taking the fender flares off and painting them. He didn't finish....as usual.

[SidecarFlip]

The only place you cannot run propane (as I said in the previous post to yours) is in a tunnel. That is Federal DOT regs.

been doing this since 1995 and I always run propane. The boiler on a fridge uses very little propane, very little. The flame is about 2 times as big as a BIC lighter.

[Dorado]

Oh I know. I just want everything working the way it's supposed to. Besides I'd still like to be able to charge the battery and things off of the truck while driving. Biggest problem I'm running into right now is that I'm wanting to run it through the fuse box on the truck but I can't find the little metal things the spade fuses plug into. I'll probably end up running an in-line fuse to it, but I'd rather hook it into the fuse box for a cleaner install. I am that picky.

[towpro]

And there's no point in using up the gas when the truck is already running. I'd rather save the propane, and utilize the truck.

my last truck camper, wolf Creek with 5 cu feet refreg would run on gas all summer, with solar providing the only power.

Last spring I started with 2 full grill size tanks April 1st.
I always watch the change over regulator for it to turn red to tell me its time to fill that tank.
But in July were were leaving for a vacation. I noticed the food was around 70 deg. the change over regulator had switched over, but never turned red so I never caught it, than it ran 2nd bottle empty.

So I went April 1st through July 15th running refreg on propane and used it all up.
I been getting grill tanks filled for $6.00 each out my way, so $12 bucks for 3.5 months is not bad.

PS: i also have a 5th wheel that sits on a spot in a 4 site campground my brother and I own. the electric usage (not including service fees and taxes) in Non AC weather runs around $20.00 per month. this is running the charger and refregerator on 120V. Maybe some electric hot water for 2 weekends every month.

It may be cheaper to run refrigerator on propane than it is electric

[Dorado]

Dang towpro. That little? I'm still going to hook it up to truck electric, but I'll keep it on auto so that it'll switch between the two. Good to know that the fridge only politely sips propane.

[towpro]

Dang towpro. That little? I'm still going to hook it up to truck electric, but I'll keep it on auto so that it'll switch between the two. Good to know that the fridge only politely sips propane.

when its running, look in the burner and you will see its not a very big flame. not much power needed.

[SidecarFlip]

Dang towpro. That little? I'm still going to hook it up to truck electric, but I'll keep it on auto so that it'll switch between the two. Good to know that the fridge only politely sips propane.

If you had bothered to read my post number 6, you would have saw that... The flame in a fridge boiler is about twice as big as a BIC lighter or not much.

[Dorado]

If you had bothered to read my post number 6, you would have saw that...  The flame  in a fridge boiler is about twice as big as a BIC lighter or not much.

I read it. But there's hearing how big a flame is, then there's hearing how long the fuel lasted.

[Backroad Joe]

Dorado, as I read your original post you are asking about wire gauge. I would agree with Towpro's example calculation and that would also match your existing 8 AWG. That should handle your needs regardless of propane preferences.

There are some that believe you need huge 4 gauge cable but I don't follow that school of thought. If you're pumping more than 10 amps into your camper battery your doing something wrong.

[RV_Tech]

The fuse size to the charge lead off your truck is the amp limiting factor from the truck to the camper. Remember if you are running a three-way fridge on DC (battery power) that power source is designed only to maintain temperature and is very limited in terms of its cool down ability (per Dometic technician training workshops). Refrigerators, regardless of selected power source draw very little. They cool down the fastest on propane.

Steve

[hooter56]

I've never tried running the fridge on 12V. It would probably quickly drain the battery?

[RV_Tech]

I was told recently by the guy giving me the orientation to my camper to not use 12V DC for the fridge. He said it could burn up the compressor?

On a three-way fridge there is no compressor. It is an absorption system.

On the models with the 12-volt compressor, they are designed to use 12-volts. If he was talking about the compressor "amping up" when voltage is low, all motors do that whether on 12 VDC or 120 VAC though there is normally protection for the compressor built-in for such an event so they shut down if they get too hot.

[SidecarFlip]

Never knew they made a 12 volt compressor fridge. I knew they made 110 volts ones and rant them on inverters but 12 volt, didn't know that. I'll take the old absorbtion fridge any day. With good air flow across the evaporator it's just as efficient as a compressor fridge and cheap to run too.