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Biily
07-27-2013, 09:59 PM
I need to store my RV for 1week with no power. How long will the propane last running the fridge. Nobody will be in and out and it's already cold and so is the food.

thanks

GOTTOYS
07-27-2013, 10:06 PM
I need to store my RV for 1week with no power. How long will the propane last running the fridge. Nobody will be in and out and it's already cold and so is the food.

thanks Should be no problem with the propane but I doubt the battery to power the circuit board and fan will last that long..Don

danemayer
07-27-2013, 10:12 PM
Hi Billy,

You'll probably run out of battery before propane. Takes several amps to power the circuit board. There are also other parasitic drains when the battery is powering the trailer. I don't know for sure, but I doubt a single battery will make it a week, even if the battery is in great shape.

scottyb
07-28-2013, 10:24 AM
I got back to a dead battery and partially thawed fridge after a 5 day side trip on Lake Powell. I only had 1 12V battery at the time. Is there anyway to minimize the parasitic draw and keep the fridge running?

danemayer
07-28-2013, 10:29 AM
I got back to a dead battery and partially thawed fridge after a 5 day side trip on Lake Powell. I only had 1 12V battery at the time. Is there anyway to minimize the parasitic draw and keep the fridge running?
The major draw is the fridge.

Greengas
07-28-2013, 10:54 AM
The major draw is the fridge.

Just wondering, how long do you think the fridge would last if I had 2, group 31 deep cycle batteries?

brianharrison
07-28-2013, 11:33 AM
I measured the amperage of my fridge one time and had a reading of 0.8A at 12.8V (approx. 10W). I believed this to be the control board current requirements.

Rounding to 1A - 7 day usage should be around 168 Ah; I would be comfortable saying a range of 150 to 175 Ah usage for the fridge, for one week.

Brian

EDIT: Just used a clamp on ammeter onto main 12V feed in fridge compartment - 0.6A at 13.5V (8.1W), non firing; 0.8A at 13.5V (10.8W) LP gas valve open, firing. Difference is probably current requirements to hold open LP solenoid.

pegmikef
07-28-2013, 12:13 PM
Brian, Isn't there a fan in there too that comes on and off periodically?

brianharrison
07-28-2013, 12:35 PM
Yes - when the absorption condenser fins reach a certain temp - cannot remember the exact temperature. I should short this out and figure out the current draw on my fan. I believe it is a small wattage (3 or 5W) but am not certain. It is to help with air circulation across the absorption unit (from bottom vent to top vent).

Brian

scottyb
07-28-2013, 12:46 PM
This is where an Auto Gen Start would come in handy. If you were leaving your rig stocked with food for an extended period of time.

scottyb
07-28-2013, 01:19 PM
Just wondering, how long do you think the fridge would last if I had 2, group 31 deep cycle batteries?

Here's a chart from Northen Arizona Wind and Sun (http://www.solar-electric.com/deep-cycle-battery-faq.html#Amp-Hour%20Capacity) .


<tbody>
U1
34 to 40 Amp hours
12 volts


Group 24
70-85 Amp hours
12 volts


Group 27
85-105 Amp hours
12 volts


Group 31
95-125 Amp hours
12 volts


4-D
180-215 Amp hours
12 volts


8-D
225-255 Amp hours
12 volts


Golf Cart & T-105
180 to 225 Amp hours
6 volts


L-16, L16HC etc.
340 to 415 Amp hours
6 volts



</tbody>

Greengas
07-28-2013, 01:26 PM
Here's a chart from Northen Arizona Wind and Sun (http://www.solar-electric.com/deep-cycle-battery-faq.html#Amp-Hour%20Capacity) .


<tbody>
U1
34 to 40 Amp hours
12 volts


Group 24
70-85 Amp hours
12 volts


Group 27
85-105 Amp hours
12 volts


Group 31
95-125 Amp hours
12 volts


4-D
180-215 Amp hours
12 volts


8-D
225-255 Amp hours
12 volts


Golf Cart & T-105
180 to 225 Amp hours
6 volts


L-16, L16HC etc.
340 to 415 Amp hours
6 volts


</tbody>


So, if I have 2 group 31 batteries that means I should have approx 200 to 250 amp hours available? Right?

scottyb
07-28-2013, 02:00 PM
So, if I have 2 group 31 batteries that means I should have approx 200 to 250 amp hours available? Right?

Yep. You could get about the same from 2 6V GC-2's for about $160. 2 Group 31's will cost a lot more than that and are still hybrid deep cycle batteries.

KWire
07-28-2013, 04:25 PM
So, if I have 2 group 31 batteries that means I should have approx 200 to 250 amp hours available? Right?

Well, not quite... It is generally recommended to only discharge your batteries to no more than 50%. Anything more and you shorten the life of the battery. So, than would mean you should only have 95 - 125 AH for the Group 31 batteries.

Ronn, take a look at "The 12volt Side of Life (http://www.marxrv.com/12volt/12volt.htm)". It is one of the best documentation on battery usage in an RV that I have seen. Be sure to look at part 2 (http://www.marxrv.com/12volt/12volta.htm).

HTH, Keith

Biily
07-28-2013, 09:30 PM
Thanks for all the input guys. I left the RV at noon today and will be gone 4 days (96 hours). I have 2 group 24 or 27 batteries, not sure but they are new. Wish I would have came back here before I left it. Sounds like with 1 battery I might make the 4 days and with 2 I will.

Greengas
07-28-2013, 09:47 PM
Yep. You could get about the same from 2 6V GC-2's for about $160. 2 Group 31's will cost a lot more than that and are still hybrid deep cycle batteries.

The dealer, CW, is "making a deal" with the batteries. Since they normally would put a group 24 battery in the coach they are giving me a credit for that battery plus CW is running a sale on their Exide batteries so I am getting the group 31 batteries for a total of $174.00. To me, that's not too bad.

wdk450
07-29-2013, 09:45 AM
A medium sized solar cell/controller (Harbor Freight Tools has them) would have probably been handy for this storage need. You don't necessarily need to permanently mount them.