Fridge on or off for travel

Nursejoe

I have a 2019 TAB 320 Boondock with factory solar. I tow the trailer with a 2017 Ford Expedition with tow package (7 pin connector). Can I leave the fridge on while I am traveling?  Does the solar still charge the system while plugged into the truck? Will the truck power the fridge while traveling? ETC. Hope that all makes sense.

pthomas745

These questions about the truck powering/charging the trailer battery can only be answered by your own experience.  There are many variables. 

The solar is connected directly to the battery, and will help charge the battery whenever the sun is out.  Doesn't matter whether it is attached to a vehicle or shore power.  Just..works.

What fridge do you have?  3 way fridge on 12V power uses between 11 and 16 amps per hour (the newer fridges use more.)  If you have the newer 2 way fridges or the CSS fridge, they use much much less than that.  In theory, you "might" be able to get enough charge from solar while driving to power the 2 way fridge and keep the battery reasonably charged.  And, if your vehicle puts out a decent charge, there would be no problems at all.

So:  which fridge?

And: with factory solar, and the Victron app, you can monitor what is happening with your battery while driving.  The app will answer your question on "does my vehicle charge while driving." 

https://www.victronenergy.com/panel-systems-remote-monitoring/victronconnect

Here is a thread that hits all the highlights on "charging while driving". 

https://tab-rv.vanillacommunity.com/discussion/10218/400-battery-not-charging-while-towing-with-frig-on-dc

Nursejoe

Thanks for an informative response. To answer your question, I have the 3 way fridge. Thanks again!

Dutch061

If it were me, I would operate the refer on propane while driving and not the 12 volt. Check your local laws abut driving with a propane operated device on while traveling, plus there are a few other things like tunnels etc. that prohibit the use of any propane device while driving.

I know, not everyone will agree with what I said but I always operated my refer on propane while driving. Our 2020 400 BDL has the 2 way refer so it is no longer a concern.

Brad

CrabTab

@Nursejoe We have the same T@B and fridge as you, minus the factory solar.

Short answer- our Chevy Colorado alternator seems to keep up with fridge demand on 12VDC as long as we are moving.

TMI Answer- We use shore power (extension cord to the house) for 24 hours with the fridge on full blast to chill it down. Once we switch to 12VDC power, the fridge gets turned to barely cooling to use less electricity for the trip. Only non critical items go in the fridge while on the road (can drinks, fresh vegetables and fruits that could survive the day at home on the kitchen counter). The critical perishable items go in a cooler in our TV. If we stop somewhere for an extended period of time we have unplugged the 7pin from the TV so we don't kill the TV battery. As soon as we get to camp we hook up to shore power or fire up the propane (if dry camping) to get the fridge chilled further down. Once there we'll move stuff from the TV to the T@B fridge. This process has worked for as long as a month on the road.

Early this spring we added 200W of rooftop solar to the mix. It is much easier to keep the fridge cold. 200W seems to put out enough current to meet the fridge demand on 12VDC.  I don't unhook the 7pin for stops anymore, as long as the sun is shining.

Edit: One additional thought- for us operating on propane while moving is a non starter. Almost any direction we travel from home starts with a bridge/tunnel within the first 30 minutes and we would need to cut it off at the inspection station.
Hope this gives you some ideas...

sgkramar

If you have a 7-pin then yes, you are providing 12V from your truck to the battery in the camper, and it is providing 12V to the fridge. The fridge pulls about as much current as your headlights, so your truck will have no problem keeping up with the current draw. Of course, if you leave your headlights on for several hours with the engine off, it will drain your battery, and the fridge will do the same thing. However, I've left our fridge running while we've eaten dinner, shopped, etc., (hour or so) and never had a problem with it draining the car battery enough to make a difference on ability to start the car.

The DC setting on the fridge is the intended setting for towing. At least, that is what my fridge owner's manual says.

AirBoss

Frankly, if the fridge is chilled to temp you can travel several hours without it operating, so long as it is full and the freezer is full. 

Otherwise, with solar and TV 7-pin you can travel all day on DC power without a concern. 

Binghi

We leave our 2-way fridge on DC power when we are traveling without any problem. I just left it running for two days on battery only (no solar or 7-pin power) after we got back from a trip - no problem. Of course the two-way is smaller, but l believe the trailer batteries will run a frig on DC for a decent amount of time if they start off fully charged.

pthomas745

A 2 way fridge in the newer trailers is not the same, energy wise, as any 3 way fridge.  The two ways average about 2 amps per hour ( or less), so yes, they "should" work on battery driving along.

The three ways use 11 amps per hour (my 2017) and 16 amps per hour (newer 3104 and 4104 models).  Those amps have to be provided continuously, not on a "duty cycle".

Viajero

For those towing with a Tesla the traction battery will keep the 12 volt battery charged and in turn the trailer battery charged thru the 7 pin. However, once your but is out of the seat for 10 minutes I believe the charge line on the 7 pin goes dormant. So don’t forget to switch the frig to propane once you are stopped. 

Cheers. 

DenverJaguar

Viajero said:

For those towing with a Tesla the traction battery will keep the 12 volt battery charged and in turn the trailer battery charged thru the 7 pin. However, once your but is out of the seat for 10 minutes I believe the charge line on the 7 pin goes dormant. So don’t forget to switch the frig to propane once you are stopped. 

Cheers. 

Or...get a DC to DC charger installed between the 7-pin and the battery that senses when the ignition is off and will kill the power even if the 7+pin is still connected. I bought the Victron 18amp charger and it seems to be doing its job. 

Viajero

DenverJaguar said:

Viajero said:

For those towing with a Tesla the traction battery will keep the 12 volt battery charged and in turn the trailer battery charged thru the 7 pin. However, once your but is out of the seat for 10 minutes I believe the charge line on the 7 pin goes dormant. So don’t forget to switch the frig to propane once you are stopped. 

Cheers. 

Or...get a DC to DC charger installed between the 7-pin and the battery that senses when the ignition is off and will kill the power even if the 7+pin is still connected. I bought the Victron 18amp charger and it seems to be doing its job. 

The idea is sound and would work on an ICE car. But the on switch for a Tesla is your Butt. Assuming your phone is on you or in the car, the car turns on when your butt hits the seat. It turns off when your butt leaves the seat. There is no switch. 

TomCanada

Biggest thing I find makes a difference is to make sure you only put prechilled items to your fridge before departure.  It's surprising how hard the fridge needs to work, even if precooled, if you throw in half a dozen room temperature cans in there. That's a lot of thermal mass that needs to be cooled.  One thing we also do is also freeze a small ice block and keep it in the freezer during travel. Works great even with th fridge off for a few hours.

Chopin

We keep the 12v fridge in our 2021 tab 320 running when traveling with no problem. We have the factory installed solar and between that and the 7 pin it stays very cold with no problem. I’d unplug the 7 pin if you are stopping the tow vehicle for any length of time to avoid draining the tow vehicle battery but other than that we never worry about it. 

AirBoss

Yes, @TomCanada is spot on. I prechill everything I can before loading. Have had no issues. 

And I use bag or two of frozen corn or peas. Works to keep things chilled nicely and has the added benefit of use as an ice pack for those nasty shin-busting episodes with the hitch! 

Da_Birds

As I learned on these forums....Always prechill the fridge before you leave and freeze or prechill anything you're putting in it. We use a separate cooler for drinks. We have 2 jugs we freeze that fit in the door shelf. If we can't fit one or both they go into the drink cooler until we have room. We also freeze any smaller water bottles and keep as many as we can in the fridge at all times. All meat gets frozen besides what may not thaw in time for our first meal(s).

We do this even if don't expect to be off shore power for long, just in case we end up without power longer than expected. Basically, we treat our fridge the same way we would treat our food/dry cooler when we tent camped. I suspect we could go a weekend without even turning the fridge on before we would have to worry about food spoilage if it's kept packed properly and not opened often.

LisaTucson

pthomas745 said:

A 2 way fridge in the newer trailers is not the same, energy wise, as any 3 way fridge.  The two ways average about 2 amps per hour ( or less), so yes, they "should" work on battery driving along.

The three ways use 11 amps per hour (my 2017) and 16 amps per hour (newer 3104 and 4104 models).  Those amps have to be provided continuously, not on a "duty cycle".

Hi @pthomas745, What is a “duty cycle”? And is it true if I have a 7 pin that it is providing 12V from my TV to the battery in the camper? Do you run your refer on DC while driving? And if so, how does your 3-way do with that?