View Full Version : 2720SL "99 question

07-16-2005, 04:30 PM
We are currently considering purchasing a 2720SL 1999 TM and have a question concerning the refridgerator. Is it possible to run the refridgerator using the TV battery while traveling?

07-16-2005, 05:13 PM

I cannot run my refrig off the 12V or it runs my TM battery down. I have an '04 3326KS with the battery in the far tail-end. Bill has measured this model and found the fully charged TM battery provides 1 Amp of current into the refrig under this condition. Of course if you stop for lunch or otherwise, your TM battery will be delivering the full 10 or so Amps the refrig draws until you start up & go again.
The problem is not in the TM but in the harness in the TV where small wiring and several connectors drop the voltage excessively to provide reasonable charge.

This is marginally tolerable if you are using hookups. The problem is it can run the battery too low. This decreases the charge capacity of the battery in the future. When dry camping it is intolerable to arrive in camp with a partially charged battery.

Other people seem to be getting along ok using 12V, and it may be those with battery up front. Some have put a switch in so they can turn the refrig off when they stop.

I have been running my refrig on 110V until leaving, pulling the plug when I leave, and not running it while on the road. Put frozen blue ice in to help keep it cool. Refreeze the blue ice in the TM before breaking camp.


07-16-2005, 09:08 PM
We are currently considering purchasing a 2720SL 1999 TM and have a question concerning the refridgerator. Is it possible to run the refridgerator using the TV battery while traveling?
Bob's experience not withstanding, I've had excellent results running the refrigerator on DC while traveling with my '02 2720SL. And yes, contrary to Bob's supposition, it works just fine with my trailer which does have the battery in the back. In fact, prior to installing solar panels, I was getting around 5 amps of charge (not discharge as Bob and Bill found) to the battery when the trailer is hooked up to the tow vehicle and the refrigerator is running on DC. Now that I have solar panels, I get around 10 amps of charge to the battery under those circumstances.

As the old saying goes, "Your Mileage May Vary". Some (like Bob) get major discharge from the TM battery while traveling and thus are forced to use alternative means (like "blue ice") to keep their refrigerator cold. Others (like me) not only can run the refrigerator on DC while traveling but can also get a recharge of the TM battery at the same time. I have had such a good experience running the refrigerator on DC while traveling that I've never needed "blue ice"...yet I always arrive at my destination (even after a full day of travel in 90 degree temps) with a fully charged TM battery, properly frozen ice cream, and unmelted ice cubes to put into my end-of-day Martini. :D

07-16-2005, 10:46 PM

I like your results better than mine. There has to be an explanation to all this. Bill is running a Ford. I am running a GM (Envoy). You have a Toyota. I wonder if you are getting a lot more voltage to the TM connector than we are. Bill's measurements showed major voltage drop in the TV wiring. I haven't measured mine. Man, its hot here in Az. I don't feel like hooking up and doing anything like that in the Summer.

Ham operators run a switched line to their radios. They use heavy wire for this. A possible solution to my dilema would be to do that as well.


07-23-2005, 06:22 PM
we have always run the refrig from the TV while under way.Never had a problem. Whenever we stop, we unplug the trailer, not to drain the car battery. DW won't drive using propane.

07-23-2005, 07:47 PM
We always run the refrigerator on 12 v while traveling - never run it on propane - in Washington it's against the law! Our charge line from the TV, a 2000 GMC Jimmy, is a 10 ga with an isolator and we have never had a problem with the TM or with our former tent trailer. You may have a smaller line if it is plugged into the TV original wiring. You can run a new wire all the way from the TV battery, through an isolator and a breaker or fuse to the plug. With the isolator, the TV battery is disconnected whenever the ignition is off, so you wouldn't run the TV battery down. With this setup we always arrive at our destination with a full battery and frozen food. In fact when we first got the TM we didn't know to only run the "frig" on 4 and we almost froze everything! LOL