Recommendations for managing battery/fridge when towing

Daisy2017

We are newbies to the towing world.  We usually throw a few ice packs in the fridge and rely on the towing battery to start getting things cold until we get to the campsite (it's often not practical to cool the fridge before we leave) and can use shore power.  I understand that our 2017 MaxS battery gets charged from the 7 point tow vehicle connection.  If we turn off the battery disconnect switch each time we stop for breaks along the road, am I correct in understanding that the fridge will stop cooling (fine by me)? I hope this is true as I have no desire to drain the T@b battery while in transit to the campsite.  My other question: the 2017 manual says that even with the battery disconnect switch on off, the 7 point connector continues to use my TV to charge the T@b battery.  Won't this drain my TV battery?  

Roamey

There is a misprint in the manual. If the battery disconnect is turned off, the battery is isolated and neither the TV nor shore power is connected to the battery and able to charge it. While driving with the battery on, the theory is that the temperature of an already cold refrigerator will be maintained. In practice, you may find the refrigerator draws down the trailer battery faster than the TV can charge it. You will need to try your particular setup and see how it works in reality. Some TVs have relays that disconnect the tow harness when the TV is shut off. Be aware there were two different refrigerator models used in the 2017 model year. The old model has one side vent on the T@B S, the new model has two side vents. 

Daisy2017

That helps - thank you!

G_and_S

Took our 2015 Max-S on a 500 mile trip to PA.  Refrigerator was left on a colder setting.  Had no problem draining either battery, but I did shut the refrigerator off if we had an extended stop. TV Subaru Outback.

Eji

Hello,I have a T@B s 2017 3 way Nordic fridge. When I am towing it to a campsite I set the battery to on and it show the green light batter icon on green, when I plug in to shore power and turn the nob to electric the plug icon is off while the batter icon stays green. It cools great, Can anyone tell me if this is correct. Should I see the electric icon light in green? 

Thank you 

jkjenn

If you cannot pre-chill before you leave, you are behind the 8 ball, already. It is really hard to cool the fridge down on DC or LP. If you pack ice packs, it should help but I would also add a frozen 32oz Nalgene bottle or two to help lower the temp. It might make more sense to not bring a lot of cold stuff and fill once you have arrived at the campsite and can use shore power. 

Roamey

Here's a picture of the controls. # 310 should be lit when on AC. This is for the newer style refrigerator. You have to manually switch it to AC mode. 

dsatwork

@Roamey I don't think this is correct. "There is a misprint in the manual. If the battery disconnect is turned off, the battery is isolated and neither the TV nor shore power is connected to the battery and able to charge it." At least I'm not sure it there is misprint or not. But my battery shut off will only isolate the battery from trailer and not isolate the battery from the TV.  I'm pretty sure it's still getting power from the TV battery and they will likely average out with each other, unless the car is running, then it would charge the battery in the trailer. 

Sharon_is_SAM

No, if you turn the battery shut off switch "OFF" you are no longer charging your battery from your TV and it is also isolated from the trailer.

dsatwork

SAM said:

No, if you turn the battery shut off switch "OFF" you are no longer charging your battery from your TV and it is also isolated from the trailer.

I don't see how that is possible, because it physically sits between the battery and the 12v distribution box. From there it can't stop the 12v supply going to the battery from the TV.

Marceline

dsatwork said:

SAM said:

No, if you turn the battery shut off switch "OFF" you are no longer charging your battery from your TV and it is also isolated from the trailer.

I don't see how that is possible, because it physically sits between the battery and the 12v distribution box. From there it can't stop the 12v supply going to the battery from the TV.

Maybe the shut-offs were wired differently at different production times?

Roamey

That's a good point and would explain the manual. I assumed they were all the same. 

cbarnhill

I agree with others-it’s better to cool the fridge before you leave. While driving, I’m on battery. If I stop (say for lunch)I  switch the fridge off. I put sticker on my steering wheel to remind me to turn it back to battery when I head back on the road. 

Sharon_is_SAM

@dsatwork I retract that emphatic statement!   Just happened to think that we disconnect the 7 pin when we stop for periods of time so the TV battery does not drain from having the frig running.  Found the quote from the manual  page 16:

"The charge in the 12-volt batteries can be replenished, depending on the tow vehicle, from the tow vehicle alternator through the 7-way cord. This charge will flow to the batteries regardless of the battery disconnect switch position. Likewise, if on or off, the solar panel is still charging the batteries."

So the battery cut off switch only isolates the Tab battery from the trailer electrical draw, not from the TV, which is why we disconnect.  There was a discussion about a year ago about needing a vehicle isolation relay installed if you want to avoid draining the TV battery.

Verna

@SAM, my Toyota Tacoma has a built-in isolator. If you turn your Siena off, you probably already don’t have power on the 7-way plug on the battery pin.  Toyota doesn’t allow any accessory plugs to be “hot” if the engine is turned off.

dsatwork

Verna said:

@SAM, my Toyota Tacoma has a built-in isolator. If you turn your Siena off, you probably already don’t have power on the 7-way plug on the battery pin.  Toyota doesn’t allow any accessory plugs to be “hot” if the engine is turned off.

That would assume that the 7 pin was installed by the factory. 

Sharon_is_SAM

I know the Sienna accessory outlets are off when the ignition is off, but we have an after market 7 pin.  A 7 pin tester should show a hot charge line.  I will check today.  

jkjenn

I can change my cargo area accessory from off to on when the ignition is off by moving  a fuse to a different position.

Sharon_is_SAM

Good for your ARB Jenn!  

dsatwork

I still have this little puppy to install.

ScottG

Marceline said:

dsatwork said:

SAM said:

No, if you turn the battery shut off switch "OFF" you are no longer charging your battery from your TV and it is also isolated from the trailer.

I don't see how that is possible, because it physically sits between the battery and the 12v distribution box. From there it can't stop the 12v supply going to the battery from the TV.

Maybe the shut-offs were wired differently at different production times?

On my 2015, the connection between the T/V and the battery is also made through the 12V distribution box located under the front of the trailer.

In this configuration, a shut off switch installed between the battery and the distribution box will not only isolate the battery from the converter, but will also prevent the T/V from charging the battery.

Unless the shut-offs (or the charge line from the T/V) were in fact wired differently in post 2015 models, SAM is correct.

The only way to definitively settle the debate is to go out and physically inspect the wiring between the T/V, battery, trailer, and distribution box on a newer model. I'd do it, but I don't have the coin to go buy a second T@B...  :-)

Michigan_Mike

I agree with Scott, you need to inspect it further as it can easily be traced.   I doubt anything down at the factory has changed so far as how the trailers are wired from year to year, other than adding in new components and technologies, etc.  

Michigan_Mike

dsatwork said:

I still have this little puppy to install.

@dsatwork is this kit a standard 12V DC cigarette style plug?  

dsatwork

@ScottG I'll check mine this weekend, when I'm out working on the trailer. But your description rings true: the 7-wire harness's first stop is at the distribution box, which would mean the battery is isolated from both the trailer and the TV when the battery shut off switch is turned to the OFF position. @SAM Sorry about that.

dsatwork

@Michigan_Mike no it's the "ARB Fridge Wiring Kit and Threading Socket" when I install the threading socket, I'm going to put another regular power socket next to it, so we can charge our phones if the car is off. An odd fact about the 2016 Kia Sorento: it comes stock with an 80AH AGM battery as the starting battery. Nice perk for someone who wants to run the ARB fridge inside the car overnight.

ScottG

I also doubt they have made any changes. The only way the T/V could continue to charge the battery with the disconnect off is if the pigtail's 12V charge line was routed directly to the battery rather than connected via the distribution box.

As a side note. I installed my shut-off (back before they were standard equipment) inside the cabin next to the converter. In this configuration, turning the switch off disconnects the converter while still allowing the T/V charge line and breakaway brakes to operate properly.

I'm not saying there's any particular advantage to this, just noting that it's a different configuration that might be encountered in some older, owner-modified T@Bs.

Michigan_Mike

I need to wire in a cigarette style receptacle in the rear bed of my Silverado so that I can run the ARB from the back as opposed to running it off my inverter in the cab and running an electrical cord out the rear window in the back seat.  I'll check with the dealership and see what they will do it for and what they use, then do it myself.  

dsatwork

@ScottG it does seem odd to me that they would wire it in such a way that the electric brakes are disabled if the shut off switch is in the OFF position. I could see someone trying solve one problem, while completely creating a more dangerous problem.

ScottG

@dsatwork, I agree, but that's the way it is on mine. Since everything (except the Zamp wiring) goes through the junction box, a battery-mounted shut-off will effectively disconnect the trailer battery from everything.

lino

Eji said:

Hello,I have a T@B s 2017 3 way Nordic fridge. When I am towing it to a campsite I set the battery to on and it show the green light batter icon on green, when I plug in to shore power and turn the nob to electric the plug icon is off while the batter icon stays green. It cools great, Can anyone tell me if this is correct. Should I see the electric icon light in green? 

Thank you 

When I use shore power on my 3 way fridge the green light initially does not go on, but it seems like once cold enough the indicator lights up green

dsatwork

@lino @Eji my AC indicator light went out and had to be replaced. The way I understand it on the 2017 Norcold180.3 model, is that AC indicator light should be on all the time, if it's on AC and the 12v indicator should only be on when you using it on 12v. That is how mine works.