Refrigerator on battery

10-08-2003, 09:59 AM

This will be our second trip in our TM this weekend. The first trip, the refrigerator didn't work, and we knew that before we left so we took food in an ice chest. This time the refrigerator is working. We want to lower the unit late Thursday afternoon and leave early Friday morning. We would like to put our food in the refrigerator before lowering the unit. Can we run it on battery, with the fan going of course, overnight? If not, what??? Any advice would be greatly appreciated.

10-08-2003, 10:12 AM

I would recommend pre-cooling the fridge with 110 volts to get the temp down to where you want it. Then on the night before turn it to DC and turn on the fan. I have dry camped for several days running the fridge on DC only and have not had a significant draw on the battery. While you are towing to your destination, the battery should recharge.

Have fun on your trip.

ColoradoCop 8)

10-08-2003, 10:58 AM

Thanks for the information! I turned it on electric yesterday at noon to make sure it is cooling, and it is. I'll leave it plugged in until we are ready to lower the unit. Our trip should be fun--the leaves are turning to their beautiful fall colors, we are going to be able to RELAX and "get away from it all" and we will see a couple of good shows in Branson, Missouri. Can't ask for anything better!

**Bill** · 10-08-2003, 01:11 PM

Well, I agree with ColoradoCop up to a point. The refrigerator draws a lot of current when running on DC (battery). You can run the refrig on battery without a recharge source *for a short time* - like late night to early morning, I suppose. But if you do this, then you start your trip with a partially discharged battery. If you are going to drive for several hours, and your tow vehicle provides a good charge rate, then the battery will recover. But if your trip is shorter, it may not. Of course, if you have hookups when you arrive, then the TM's converter will recharge the battery, and all is well. But if you will be dry camping, you start out at a big disadvantage. There is no universal answer, except "it depends".

A real good tip that appeared earlier on this board is to go to a hardware store and buy a short but heavy extension cord. There are flat ones, 3 feet long, #10 or #12 gauge, that are ideal for the purpose. Before you close the TM, plug the TM's heavy power cord into this extension cord (using an adapter), push the heavy power cord back into its cubbyhole, and let the extension cord hang down the outside wall of the TM. Now close the TM, leaving the plug end hanging outside - the cord will fit between the seals. Once closed, plug the extension cord into house power (using another extension cord that you will leave at home). Now you have AC power on the TM's converter, and it will keep your battery fully charged all night long. In the morning, unplug, tuck the end of the shorty cord up behind the seals, and go.

For what it's worth, the Dometic Refrigerator Owner's Manual specifically warns against running the refrig on battery when there is no source of recharge current for the battery. Their concern is discharge of the tow vehicle battery to the point where it won't start. But the same thing happens to your TM battery.

If you decide to proceed as you describe, Colorado's tip to pre-cool the refrig is critical. And be sure to stuff it with only pre-cooled (cold) food.

Colorado - you successfully did several DAYS of dry camping with the refrig on DC, rather than gas? Aside from the question of WHY, that's amazing!

Bill

RockyMtnRay · 10-08-2003, 01:45 PM

As someone who routinely dry camps...and who packs/closes up the TM the night before a trip, I heartily second Bill's recommendations and cautions against extended powering of the refrigerator from the TM's battery. The longest I would expect a healthy, new, fully charged Grp 27 battery to power the refer is about 6 to 7 hours...much less if it's not new or fully charged.

An alternative way to keep the battery charged when your TM is closed up before trip departure is to connect a heavy duty battery charger to the TM's Tow Vehicle umbilical plug. I (and I believe Mike Laupp) have found this works quite well and doesn't involve leaving a cord hanging below the TM as the AC solution does.

Note: the concerns about hydrogen buildup discussed in this thread also apply to powering a closed TM via an AC cord. My take is this is not a particularly serious concern or TM wouldn't have made it easy to power a closed 2004 TM.

**Denny_A** · 10-08-2003, 08:12 PM

Quote:

A real good tip that appeared earlier on this board is to go to a hardware store and buy a short but heavy extension cord. There are flat ones, 3 feet long, #10 or #12 gauge, that are ideal for the purpose. Before you close the TM, plug the TM's heavy power cord into this extension cord (using an adapter), push the heavy power cord back into its cubbyhole, and let the extension cord hang down the outside wall of the TM. Now close the TM, leaving the plug end hanging outside - the cord will fit between the seals. Once closed, plug the extension cord into house power (using another extension cord that you will leave at home). Now you have AC power on the TM's converter, and it will keep your battery fully charged all night long. In the morning, unplug, tuck the end of the shorty cord up behind the seals, and go.

Bill

An even better solution is to run that same custom extension cord from inside the power cord compartment, thru the floor and into the bumper compartment. Then an extension cord can be plugged into it from the house. Trailer can be closed overnite, with the reefer operating from the house power. Preparation for departure is to remove the bumper compartment lid, unplug, stow the ext cord, replace the lid and hit the road!

Denny_A

**Bill** · 10-09-2003, 09:39 AM

Yes! That's the right way - I forgot that one, Denny. Requires cutting a small hole in the floor of the rear compartment, but that is really easy to do. BTW, I am under the impression that the 2619s don't have that rear compartment. How would it work for those owners?

Bill

**Denny_A** · 10-09-2003, 09:58 AM

Quote:

Yes! That's the right way - I forgot that one, Denny. Requires cutting a small hole in the floor of the rear compartment, but that is really easy to do. BTW, I am under the impression that the 2619's don't have that rear compartment. How would it work for those owners?

Bill

Bill,

Easy answer! I don't know. :

Denny

**mjlaupp** · 10-09-2003, 10:32 AM

Quote:

BTW, I am under the impression that the 2619's don't have that rear compartment. How would it work for those owners?

Actually there is a small 2-3" deep compartment between the tub and the outside back wall of the 2619 TM. It is where the power cord is stored. You can see this area in the larger models with back access storage. It should be possible, with very carefull measuring and drilling, to get an extension cord into this area. You would have to remove the bumper storage pan and drill from below. The question then becomes: How do you plug the shore line plug into this extension cord? Perhaps by installing a small access door in the fixed rear bathroom wall just above the tub and close to the street side wall.
MJL

**Bill** · 10-09-2003, 02:06 PM

Mike -

Re the 2619 - I was afraid of that. Pretty complicated to set up, and to use. In this one case, I think I would revert to the original suggestion - the flat extension cord. Otherwise, Denny's approach looks pretty good to me.

If you use the flat cord approach, the end of the flat cord doesn't have to hang out in the mud when you drive away. Either wrap it around the corner of the TM and capture it in the bumper compartment under the diamond plate. Or push it up past the seal and into the space between the lower body panel and the upper (rear) shell. Might scrape paint there, I suppose ...

Bill