Wolf,

Can't I run the fridge in 12v while driving? Then turn it to LP when stopped?

 

I'm going to jump in here and say that the 12v system can keep the fridge cold, but it does not have enough juice to cool things down. Cool it all down on the LP, leave the door shut and switch it to 12v.
Still gonna pull a lot, I think. Have an alternator budget ready.

 

When driving - the fridge runs on 12V (from your alternator) AND LPG.

That is what it is doing.

You can run it on LP when you stop - but WHY? If you have a 115 hookup, USE IT....

Unless it is primitive camping....

Spare your gas if you can. This is called "ENERGY BUDGETING".

It costs more to run gas than park supplied electric. You paid for it in your site fee, so why not?

BE CONSERVATIVE.

 

But you are wrong.

If you pay a fee for the night, use it to run your stuff. ALL OF IT!

DON'T WASTE YOUR GAS!

The 115 system cools just as well, but you don't use any of your LPG.

12V is essential for both systems. When you are plugged in - that 12 volts is supplied by your convertor.

But for one - you burn gas.

For the other, 115VAC electricity supplies the same heating of the cooling unit in the fridge. In the next issue you will see why. But it comes from the docking connection you PAID FOR with your camping fee.

In place of the tiny little "BIC LIGHTER FLAME", a heater running on 115 AC current (similar to an old fashioned soup cup heater) is used as the heat source in the cooling unit.

(?) Come to think of it, I'm not entirely sure I know what you mean there.

"12V system". It is used by both.

One is gas, one is A/C from the trailer connect.

It is late - I will come back to this and see how it is shaping up tomorrow.

CIAO

 

ok, lots of good info here. i am not drawing on my altenator to run thungs. i charge my camper days pryer to leaving with my household 120v, as well as cool my fridge. while on the road it is plugged into the trucks 12v(although i see your point about the extra altenator draw and believe it would be fine without power for certain distances). not sure exactly what was being said about driving while powering with propane, but i'm pretty sure up here it is illegal or atleast frowned upon, so my bottle is shut off while in transit.
where i camp in my area there are no 120v hook ups so my fridge is solely run on propane. i unplug my 7-prong connector when i arrive and run only off my camper battery so as not to drain my truck batteries.
what i was doing(keep in mind this whole camper thing is brand new to me), was plugging my 7-point back into the truck when my camper battery died and running the truck to recharge it. until i was told at the campsite that i would have a better chance of documenting the grass grow(changed from the original phrasing to eliminate possible repremand)
that being the reason for my original question
i'm having a hard time following the last statements about 115ac really being used as 12v or using 12v while using gas.
i know when i take the outside cover off and have access to the rear of my fridge, it is plugged into a 120v(115v)outlet and is drawing 120+/-volts when being operated from household power. also from my understanding when it is operating on gas there is no 12v involved. burning the gas supplies the heat and that is all that is needed. those are my theories so please correct a rookie camperite if i am wrong.

ok now it is getting late for me.

if any of this didn't make sense its because it didn't make sense, make sense?

 

Ok, as I read it

Before trip, 120 (121 whatever it takes) charge up batteries/cool down fridge

During trip, run fridge on 12V while on road.

Priimative camping, (or sleeping at a truck stop) LP

Destination, back to 120 if possible

 

I agree and practice everything you have said here.
I've also had the back cover off of my Dometic and it's basically a 12v system with LP. If I'm plugged into the grid the 115 is reduced to 12 before it powers the fridge and I'm thinking about modding the power supply with a switch somewhere so I can use the electric while on the road. (I don't have the 12v option on the control panel of the fridge, 115 or gas only. )
But that's a side issue on this thread.
But what did I say wrong? I always thought that the 12v electric was a heavy draw and it needed the 115v power supply to be able to provide the amps necessary at 12v to get the job done. (The main reason I haven't modded the power supply.)

 

The 12V portion of the modern RV refrigerators only controls the operations of LP or AC.(3-way units however do have a separate 12V element that is intended to keep the refer cool only, does not have enough wattage to cool from room temp, these are usually found in motorhomes only) The heating element for AC operation is actually a 120V AC element

 

LOL we gotta awhole bunch of nutin going on here folks.


Wolfie yo must be getting old.

I would bet that hes no where near a 120v outlet to plug his camper into. If he was he wouldn't be asking how to keep his battery charged.
I would also bet his fridge isn't a 3 way so thats out the window also.

Burd your on the right track even with all the stuff that was trying to be said.

You would be best to add an extra battery like I said before and if you still have both batteries go dead I would look into a genarator like Blackhat suggested. Charging a battery using your truck will take a long time and prob won't help you to much to go that route. The biggest 12v draw your going to have is that furance blower so keep that in mind and use your power wisely .

 

OK, I was mistaken when I looked at the back of my fridge. I didn't realize there was more to it than that.

 

Sorry to hijack the thread. Let's take the refer discussion on over to the thread that Wolfie started for refrigerators.
Like what has been said, if you are going to dry camp, one battery will not be enuff. I use 2 6V golf cart batteries in my rig and can go for several days if we conserve power. The best way to conserve during cold weather is to resort to alternative means for heat, catalytic heaters will warm a trailer well and use no electric power.

 

[QUOTE=firesoutmatt]
I would also bet his fridge isn't a 3 way so thats out the window also.

sorry, but i do know what i have in my camper

it is a 3-way fridge. one setting for elec, one for gas and on for 12v.

anything else you figure is out the window? i'll admit i'm green to the goings on of campers, but give me a little more credit please.

 

[QUOTE=durtyburd]It's unusual to see a 3-way refrigerator in trailers because of the amount of draw on the batteries. They are mostly installed in motorhomes and used on 12V when under way so the alternator keeps the batteries charged.

 

[QUOTE=durtyburd]Sorry Burd it wasn't ment as an insult. I've only seen 3 way fridge in motorhomes and usally campers that have on board gens to keep the batteries up. If you do have a 3 way thats great but doesn't help your problem in any way. To make sure you do have a 12v on your fridge look at your fuses . There should be one thats for the fridge. Another way to check is to unplug the 120v plug and turn off gas. Let it sit for a day and see if it stays cold. All so if its not a 3way when you do that the check light will come on the front panel.

I was just trying to help your battery problem and this whole thread went into a tailspin somehow. So if your fridge is a 3way make sure its not on 12v . Some fridges are auto and will switch bythemselfs . Thats all I was trying to say .

 

no worries.

i think now i've got it figured out.

conclusion: extra battery for now. gen set later on down the road.

thanks guys!