Refrigerator on 12v

[jlenter]

My 3-way fridge runs equally well on propane and 12v. Is there a downside to running on 12v all the time? It doesn't require me to refill the small propane tank. Is it hard on the inverter?

[avanti]

Originally Posted by jlenter

My 3-way fridge runs equally well on propane and 12v. Is there a downside to running on 12v all the time? It doesn't require me to refill the small propane tank. Is it hard on the inverter?

Nah. You only want propane when dry camping.

[avanti]

Originally Posted by jlenter

My 3-way fridge runs equally well on propane and 12v. Is there a downside to running on 12v all the time? It doesn't require me to refill the small propane tank. Is it hard on the inverter?

Nah. You only want propane when dry camping. Saves battery.

[WJones]

Originally Posted by jlenter

My 3-way fridge runs equally well on propane and 12v. Is there a downside to running on 12v all the time? It doesn't require me to refill the small propane tank. Is it hard on the inverter?

If you have a 3 way fridge, it can run it on propane, 12V DC or 120V AC.
If you're plugged into shore power, the best is 120V AC. It just avoids having your converter change the 120V AC of your shore power to 12v DC before using it.
If you're driving, you can use 12v DC from your house battery. It should be recharged as you drive by the engine alternator. Be aware that when you stop, the battery won't last too long when running the fridge.
You will have to use propane when parked for any length of time at a location without shore power.

[jlenter]

Unless you consider a two hour layover for a meal dry camping. I was not specific enough in my question. Fridge and freezer get very cold on 12v & propane. On 110 the freezer freezes but the fridge only gets to 50 degrees. Given that I always have shore power when parked "Is there any reason I should not use 12v and save the propane?"

[avanti]

Originally Posted by jlenter

Given that I always have shore power when parked "Is there any reason I should not use 12v and save the propane?"

Not really. Running on 120VAC is slightly more efficient, but who cares? Won't hurt your converter. That said, it is odd that your fridge doesn't work well on 120VAC.

[eric1514]

Originally Posted by avanti

Not really. Running on 120VAC is slightly more efficient, but who cares? Won't hurt your converter. That said, it is odd that your fridge doesn't work well on 120VAC.

That's what I thought. I could be wrong but I would have thought that the same heating element is used for both AC and DC operation.

[jlenter]

I appreciate the counsel.

[hbn7hj]

I would replace the AC heating element and see if things improve on AC. The AC and DC heating elements are separate parts.

[jlenter]

If there is no harm in running on DC why bother?

[eric1514]

Originally Posted by jlenter

If there is no harm in running on DC why bother?

Because some folks, myself included, like to have everything working as it should.

[hbn7hj]

Why bother? On DC you lose the auto switch to propane if it fails and there is much less stress on the converter. Direct AC is more efficient but that isn't much of an issue. I think you should fix it. Just an opinion.

I had the DC connection melt due to heat. Use DC when stationary only when the propane won't work. Again, just an opinion. Save the DC for driving.
Harry

[jlenter]

Thanks for the input, Harry. Stress on the converter was my initial concern. My unit is almost 20 years old and I haven't read anything about it automatically converting from AC to propane. It uses very little propane and works very well on propane and DC so I thought I would save the trouble of watching the propane level. But, if there is a chance it is harder on the converter I will go with propane.
Thanks to everyone. This was my first post here and the input was great.
Jeff

[jlenter]

Thanks for the nudge, Eric. I am generally that way but RV ownership is new to me and there are so many things to think about with a 1998 unit. I'll see if I can figure out how to replace that AC heating element.

[avanti]

I am not at all convinced that properly-spec'd converters "wear out" with use in any practical sense. Why do you think the fridge is "stressing" it?

[jlenter]

think it is stressing it. I don't know anything about converters other than it seems to make a little noise and generates a little heat. So, I wondered if it is a part I should use sparingly or simply enjoy.

[hbn7hj]

There are a lot of connections between the converter and the DC heating element. Fuses, relays, and screw connections and maybe even wire nuts. In my case slight resistance in the DC connection melted the nylon fitting while driving. Thirteen amps or whatever it is can cause some heat. True, the converter may be able to do it but I agree with the other guy. Fix the AC element. Use the DC for what it is meant for: driving or when the other systems are waiting to be repaired.

By the way, that $2 nylon fitting was $21 from dometic. I don't think we were close to a fire.
Just an opinion! If DC works for you then do it. Harry

[wincrasher]

Why not run the fridge on DC? Because it's 12-15 amps, that's why! Do the math and figure out how long your battery will last.

When it's especially hot outside, I've found on DC the fridge can also become overwhelmed by the heat and not get down to the temps I'd like.

When driving, it's a good way to go if the temps are not too high - saves propane and avoids wind blow-outs some have experienced. The trick is to remember to switch it back to 110v or propane. Most people forget and end up with dead batteries.

[JohnnyFry]

No, they are two separate heaters.

[JohnnyFry]

No, they are two separate heaters. I am not sure if they are different wattages on all units. My unit runs 14 amps on 12volts and 2 amps on AC which would indicate that the AC heater is more powerful on my unit.