Refrigerator Power Priority - AC/12V/LP?

[nmken]

All:

I'm wondering about how to best power my refrigerator during travel.  I've been using 12V and note that on some days it can warm up quite a bit.  I had read once in an unreliable forum that LP provides greater cooling than 12V and am wondering if anyone can confirm or debunk this notion?  Currently I save LP Power for campgrounds that have no services.

Thanks
Ken

[shovelhead]

Ken I've left mine on "Auto" which about 99% of the time is LP even when I'm on shore power. I've had issues with shore power having brownouts. This causes my fridge to go into a error condition "E0"

[david]

I once saw wattage figures quoted for an RV refrigerator on 12V DC vs 120V AC. The 120V AC was three times higher. So that seems to confirm that AC will cool faster. And I also think that LPG will cool faster still but not as great a change as DC to AC.

But since I never camp where 120V AC is available (well so far) I leave the fridge on LPG all of the time when we travel.

David

[charliem]

[font size="3"]Ken,

From my experience and calculations the priority should be propane, 120V if available, 12V never.  The 12 volt option is really a hangover from times past where folks worried about safety on the road. Today's LP bottles come with flow rate limiters that essentially shut off if a line is broken. The larger fridges, such as in the 21s, don't even offer a DC mode. I leave mine on auto which uses propane on the road. When 120V is available the fridge switches to AC, but switches back to propane in the event the CG 120V goes down.  For my 7 cu ft fridge the cooling is approximately the same for gas or 120V.

Some of the smaller fridges offer a 12V option, but my numbers and experience indicate the DC mode is far less effective than either of the other two. And it will suck a battery dead before you can even get the brew bottle open. Running the fridge on DC while traveling will essentially eliminate battery recharging, and my even yield a negative charge rate. As I said: 12 volt never.
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[pinstriper]

I'm gonna say this about never using DC: "Bah!"

I still leave the propane off while in transit because I don't trust the switches to keep the furnace off, and us (well, not ME) to be sure we (again...not ME) didn't leave the hot water heater on.

I turn the fridge on AC the evening before we load for a trip, or at latest morning of the evening transit, and we camp with hookups. So the battery is fully charged when we leave. I'm not depending on the ride to recharge the battery. The fridge on DC is just to keep it cold. So pretty much I'm not running the fridge off the battery, but off the alternator.

Now, for those who boondock/dry camp, I retract my first statement.

[swbc150]

I've been rving for over 20 years. I always precool the frig here at the home before I leave on the house current. When I pull away from the curb the Frig is on LP and stays on LP till I get back home. LP cools the best and as said before no worries when traveling and 12V is the worst option they ever offered on these RV Frigs.

[whoofit]

My TV does recharge the battery while running the fridge on DC just fine. To the tune of 30% in 1:45 of highway driving. Not sure why but there you have it. We always travel in DC mode. Like Pin, we start with cool food to begin with... with only 2 x20 lp tanks it's worth the conservation effort we feel. And who really knows for sure how much lp is left in the tank to begin with? Unless you have an auto changeover, and it works. But we are simple folk.
 
We really like or DC option. Can you tell?

[mitch]

For those that leave it on LP during travel, is there any concern with the flame blowing out because of wind?  I kind of just assumed that the flame would blow out and the ignitor would just be working extra hard to try to relight it.

[david]

The one time I travelled several hundred miles with the propane on and the fridge burner lit, the pilot did not blow out. Even if it did the igniter system would try once and if it didn't light it would trip out.

I think that there is little chance of the main burner blowing out underway. Maybe a greater chance of the pilot blowing out. But if it did then when we stopped we would see the error light, then we would reset and relight the pilot. All with little temperature loss inside the fridge.

David

[ctmark]

When we first got our trailer, we drove for 4 hours with the frig on 12V and had a nearly dead battery when we got to our campsite.  We took the trailer in for service after we got back to get the wiring checked and all was ok.  We may not have adequate wiring from the tow vehicle to the trailer battery to keep the battery charged.  
Since then, we always use propane on the road and it works great!

[swbc150]

No issues ever with a blow out pilot light. It is well protected, no need to worry about it. I have driven through 50+mph winds on the highway and the Frig was still running fine when I stop for a break or for the day.

[swbc150]

One of the ways I conserve my Propane is Not to leave the Hot Water Tank on all of the time once I get to the Campsite. Once I know I need hot Water I then turn it on ahead of time, like for dish washing or a shower, then off it goes.
Running the Frig on Propane once I leave my Home and then back home has never seen allot of use of the propane and once at the campsite will dictate to the amount of the cooling you need with the Frig setting.

[whoofit]

[p]So we did DC on the fridge again with our 2:45 trip home yesterday with a much different result than before. This time we only saw a 10% rise in SOC. While wondering what went wrong this time I heard a faint humming sound, actually felt the vibration first. I left the water pump on with a completely dry fresh water tank. It must have been on the entire trip....Doh![/p][p]
[/p][p]Can't work up the courage to see if the pump still pumps.[/p][p]
[/p][p]Also figured I'd add that our experience has been under mild ambient temps. The duty cycle is probably lower than it would be in the heat of the summer. LP may be the only way then. It'll be fun to find out.[/p]

[shovelhead]

My 2014 cl21rbs is LP or 120vAC no DC option

[nmken]

The way I'm leaning is that to travel with 12v as long as the refrigerator is maintaining temp and switching to propane only if I need to catch up.  There is much speculation on the web about laws about propane but from what I read, it is legal everywhere unless specifically called out and even then the restrictions (ie for tunnels) are for propane loads much larger than a 2 20 lb bottle set up.  I've seen comments about not having igniters enabled at gas stations but haven't found any actual laws to cover this - can anyone come up with anything beyond opinion on that matter?