Battery/ Fridge/Towing

Tea · November 2018

I have a T@b 320S. Can I run the refrigerator with battery on while towing?

jgram2 · November 2018

@Tea We have the 3 way fridge-propane, 12V, 110 in our T@B, and never use the battery for it because it’s a hog, drawing ~3 amps/hr. While propane is very efficient, we don’t use it under tow due to state laws and perhaps an excess of caution We just turn it on in our driveway on shore power 24 hours before we leave, put a 1/2 gallon of frozen water in, and don’t open the door while traveling. Our small cheap cooler contains our traveling food and beverages.

Sharon_is_SAM · November 2018

The 3 way frig on DC draws up to 11 amps and too many owners report that their TV alternators are not able to off-set the draw from the frig and the TaB battery becomes depleted. Someone recently began running the frig via an inverter while towing and has had success - see last thread.

These may be helpful.

https://tab-rv.vanillacommunity.com/discussion/383/normal-battery-drain-or-problem/p1

https://tab-rv.vanillacommunity.com/discussion/1661/using-your-3-way-fridge-my-lessons-learned/p1

https://tab-rv.vanillacommunity.com/discussion/6053/operation-of-norcold-3-way-fridge-via-inverter-during-travel

jgram2 · November 2018

Oops! I thought 3 amps per hour was bad!

MuttonChops · November 2018

I'll disagree with the generalization "too many folks report problems due to the tow vehicle alternator not being able to off-set" the 3-way Fridge current demand. People having issues do make posts to seek help while most of us that use 12VDC from the tow vehicle don't post about our non-problems.

It is important that you research, learn, know your specific tow vehicle. In general vehicles intended for towing like larger SUVs and pickup trucks do just fine. Vehicles designed for passenger use that can tow tend to see more initial problems until the tow vehicle wiring is modified.

As an example many newer vehicles use variable output alternators however most of those also automatically switch to higher output when the Headlights are turned-on.

Example

Chevy Colorado Real-World Data

'Haul On' = Tow/Haul Feature that modifies several driving parameters

'Lights On' = Normal driving mode with just headlights on (higher output)

Image: https://us.v-cdn.net/5021717/uploads/editor/xi/e7mymyb2azhs.png

Other factors to research/watch for are tow vehicle wire sizes, most with a 7-pin factory installed connector are 30A while some like the Honda Ridgeline are 20A. Read your owners manual. Ask here if others tow with your vehicle. Check your vehicle forum for alternator/towing discussions.

Dcarlton · November 2018

I just chill it down before I leave by plugging in and turning it on the night before. Sometimes I will put a bowl of ice in if I want to chill it quickly. I fill it up with my supplies, toss a couple of frozen water bottles in, turn it off, and go. It’s always plenty cold two or three hours later when I arrive.

I really like the three way fridge. It’s silent which is important to me. I never have any trouble lighting it, and I think it works nicely.

rcuomo · November 2018

Just an FYI. According to the N180.3 installation manual it draws 11.7 amps @ 12v. As mentioned by Dcarlton, I prechill on 120v and then switch to 12v while towing. I tow with a 2017 Ridgeline and it has no issues maintaining temp and keeping up with the amperage draw while towing.

ScottG · November 2018

@Tea, the short answer is yes. The 12V setting on the 3-way fridge is intended to be used while towing (and only while towing). This of course assumes that you have a properly wired 12V charge line on your tow vehicle's 7-pin electrical harness.

That said, I find that when using the 12V setting, my tow vehicle can't quite keep up, and the T@B battery gets a little depleted en route. Because I mostly dry camp and like to arrive in camp with a full battery, I usually do what jgram2 and Dcarlton suggest (pre-chilling and throwing in a block of ice) when heading out. When returning, I will run the fridge on 12V if needed, because I can always top up the battery at home.

And, for the record, I agree with the generalization of "too many" people reporting issues. It applies to me, and that's one too many! ;-)

Istokpoga · November 2018

Personal experience with our 180.3 is not as satisfying on 12v. TV is older Nissan Titan wi/ tow package. 130A capable alternator, 30A fused wiring to 7-pin. With fridge stabilized at 35-37*F the temp will rise to 52-59* within 3 hours of (Florida) driving, say 80-90* ambient. I have not yet addressed the known mods of heavier 12v wiring to and from the fridge, directly to the battery. The battery does not get drained at all under these circumstances and will stabilize at about 12.7V after a full day of this (after surface charge dissipation), which tells me the TV is providing adequate amperage-the fridge just doesn't keep up.
Fortunately, the fridge operates just fine at any road speed on propane and has only "blown out" once in several thousand miles of travel, including interstate. I just check it when we stop every two or three hours
Just my $0.02, and my experience doesn't presume others are somehow wrong.

Sharon_is_SAM · November 2018

@Istokpoga, so in your case, it appears the frig can’t draw enough voltage to keep up with higher ambient temps?

Istokpoga · November 2018

@Sharon_is_SAM that is correct. It does run-the fins stay cool and you can feel the heat at the exterior vents. Some, as I said, have reported using heavier gauge 12v wiring and grounding directly to the battery as helpful.
This is our third rv, first trailer, and I've always had good luck using propane-very efficient. I do generally shut it off around busy gas pumps for good measure, even though the gas fill on our TV is on the driver's side.

TomCanada · January 16

This is an older thread but wanted to share a little hack that works for us. Our 3-way fridge in our Tab 400 significantly discharges the Tab battery while towing (our TV is an X3). Seems the TV can't provide enough juice. But if we turn off the battery (via disconnect switch) before leaving the driveway, the TV suddenly can provide all the current the fridge needs. It seems that if I leave the battery connected, somehow either the converter is deciding to give most of the fridge's supply from the battery (with only a little from the TV), or the TV is somehow deciding that hey - there's a battery, so I'll give less juice to the fridge myself. Either way, disconnecting the battery seems to allow us to travel as long as needed with the fridge fully powered by the TV. Woo! Hope this helps others..

AnOldUR · January 16

TomCanada said:

... if we turn off the battery (via disconnect switch) before leaving the driveway, the TV suddenly can provide all the current the fridge needs.

First, you should NEVER tow your T@B with the battery disconnect off. It disables the breakaway braking system.

Second, if the disconnect is off you are drawing power for the fridge exclusively from your tow vehicle battery. If your alternator can't keep up, you may be depleting your tow vehicles battery instead of the trailer battery.

TomCanada · January 16

AnOldUR said:

TomCanada said:

... if we turn off the battery (via disconnect switch) before leaving the driveway, the TV suddenly can provide all the current the fridge needs.

First, you should NEVER tow your T@B with the battery disconnect off. It disables the breakaway braking system.

Second, if the disconnect is off you are drawing power for the fridge exclusively from your tow vehicle battery. If your alternator can't keep up, you may be depleting your tow vehicles battery instead of the trailer battery.

Good point about the breakaway - I would hope that's wired before the disconnect switch (I'll check).

Regarding draining the car battery, if my Tab batteries are fully discharged, battery is connected, and I'm driving with the car charging batteries *and* supplying the fridge, if that was a problem we would've heard a lot about that problem from the RV community - but that doesn't seem to be the case, so seems alternators can typically handle a fridge+battery (charging) load without issues (just a fridge alone would be even lighter a load to handle). Either that or we've just been lucky and the TV batteries have never had an issue

Grumpy_G · January 16

Historically the small 3 way fridges were intended to go into small camper vans where a ~11 amps power draw can easily be covered by the alternator. Most tow vehicles have a 20A fused 12V connection to the trailer and theoretically can run a fridge in the trailer. However the dreaded voltage drop rears its ugly head again. As long as the trailer battery has a higher voltage than what comes from the tow vehicle the battery is the primary energy source. Once the battery gets drained down enough (or is removed from the equation) the tow vehicle keeps the fridge running.
A DC-DC converter can "cover up" the voltage drop from the tow vehicle to the trailer battery but it opens another can of worms because it increases the current draw from the TV, often to the point that the fuse blows.

jbajor · January 17

I never turn fridge off! get everything cooled down on shore power before you leave,,, it will 'cycle' so not pulling full power all the time. Do you have solar? That will more than make up for the fridge draw while towing too

Marceline · January 17

jbajor said:

I never turn fridge off! get everything cooled down on shore power before you leave,,, it will 'cycle' so not pulling full power all the time. Do you have solar? That will more than make up for the fridge draw while towing too

Don't you have a 2way fridge? That's a completely different situation than the 3way fridge running on DC power.

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