Fridge operation

plrock55

Hi all,

I am getting ready for my first outing with 2018 T@B 400.  Just want to understand fridge operation while towing. Is it correct to assume that while connected to TV that the fridge is still draining battery charge? What is the best setting for  fridge while towing? I have it plugged in now as I prepare for my trip. Once underway if I set it between 1-2 will that be sufficient to keep things cool and not deplete the battery too much? Or does TV keep battery charged. Should I turn on the inverter?

Not sure if I asked these questions correctly. I am sure when I return from my first outing I will know a little more about what I don't know!

Thanks to all in this forum for being so helpful to us newbie.

pthomas745

What fridge and battery do you have?  

I'm collecting battery conversation snippets.  Here is an answer about a 2018 400 2 way fridge: 

"....the 2 way fridge in a 2018 400 is an Isotherm Cruise 65 2 way fridge.  The spec sheet says it can use 360 watts over 24 hours (about 30 amps from your battery on 12v).  Nucamp told another owner the wattage was 275 watts."

What that "30 amps from your battery on 12 volt for 24 hours" means is that fridge will use about 2 amps per hour. (or less). In theory, your vehicle should/might keep up with that small draw.

If you have the 3 way fridge......?   3 way fridges on 12v consume amp hours at very high rates......13-16 amp hours.

If you have installed solar.....you can have your co-driver check the Victron app while you drive (if you have the Victron controller installed) and see how  your vehicle charges while on the road.

falcon1970

What tow vehicle are you using?  Apparently not all tow vehicles can charge the trailer battery while underway.  Some can provide a charge  but require the headights to be on. Check your vehicle.  If you have a Victron battery monitor you could connect your vehicle and see if the vehicle is adding any charge to the battery.  You may need to have the engine running at higher than idle though.
The inverter is not connected to either the 12v fridge or the 3-way fridge, so turning the inverter on will just add an additional drain to the battery but have no effect on the fridge.
With the 3-way fridge you could run it on propane while underway but the consensus (and I agree) seems to be that it is a poor practice to have a propane operated system running while underway.  In addition you may run into issues while driving through a tunnel or over some bridges.  Even on some highways (NY I think) it is illegal to run a propane system while underway.
I set my (12v) fridge to "3" and that seems to keep things properly cool/cold.  I have overnighted in rest areas and Walmarts and not had a problem with the fridge drawing the battery down very much.  I tow with a Ford F-250 though and it does a very nice job of keeping the battery charged on even relatively short trips.

Denny16

plrock55 has a 2018 TaB400, which only had the 2-way 12VDC/AC fridge, a Norcold 1.7cu ft. NR751BB "Power consumption (W/24h) = 360 W, 30WPH.  He/she has either a single 200 amp AGM (2018’s made up to Jan 2018) or two Harris 6VDC AGM 234 amp batteries.

@plrock55. We have a 2018 TaB400 also, and tow the trailer with the fridge set to 3, this keeps the food cold, as the TaB is going to warm up a bit whilst towing, so I would not set the temp too low. The fridge is a fairly efficient compressor model, not the three way most TaBs had previously, which would drain the battery quickly in 12VDC mode.  You only have two choices AC when connected to shore power, and DC off the battery when not connected.  Do Not turn on the Inverter, it is not connected to the fridge anyway.  This will only drain your battery quickly.

Depending on the tow vehicle, you may get some battery charge whilst towing.  I assume you do not have solar, for boondocking, you might want to consider getting two 100-watt portable panels or at the minimum a 100-watt solar suitcase portable panel to charge the battery when camping without external power hookups.  You can reduce the fridge load whilst towing by getting the fridge cold, along with its contents, by plugging the fridge in overnight (on shore power) set at 4-5 before you hit the road.  A quart of frozen water will help keep the food cold and you have cold water once starts it to thaw.

The two way fridge is not going to drain your battery significantly, even during a 8-12 hour towing period.  You have at least 200 amps, the fridge averages 1-2 amps an hour when running (which is not consistently, it cycles on/off like your home fridge).  So you can go for two or three days running the fridge and lights while camping, and still have some battery power left.  
Happy camping
cheers

Horigan

We're drifting on our nomenclature again.  For example, the battery has at least 200 amp-hours of electrical capacity.  The fridge draws 2 amps, so you have 100 hours of theoretical capacity, but following the 50% discharge rule the battery has 50 hours of capacity.

Amps is an instantaneous rate of electrical flow, so you don't need to say amps per hour.  You could say the frig draws 2 amp-hours per hour, but that just equals 2 amps.

Class dismissed. 

Denny16

True, I was keeping it simple, not technically correct.  BTW, you can take an AGM battery down 80% of max capacity, so you have a 160 to 180 amp hrs of battery capacity you can use.  It is flooded lead acid batteries that need to stay at 50% of charge level. 

Several TaB400 owners without solar have reported going boondocking for two to three days off the 200/224 amp/hr batteries without any problem, this includes using the Alde at night, and no inverter or other high power devices used.

With solar you can keep going until you run out of food, water, propane or your holding tanks get full!

cheers

plrock55

Thanks for all of the comments. Denny16, I have 2 way fridge, factory installed solar and a new 12v Interstate battery 200 ah..So thanks for the tips. Sounds like I should be ok keeping my fridge cool while traveling.

I tow with Toyota Tacoma.

Appreciate the feedback. My first journey will be informative for sure.

Paula

Denny16

Grand, you have the same setup as we do, same replacement battery also.  You didn’t mention having factory solar, which should keep your battery charged, even with only partial day sun.  We added two portable 100-watt panels and a second Victron to go them to supplement the roof solar, when the TaB is parked under trees, or a shade roof.  

@plrock55, What is your month/year build date, it is on the driver’s side of the tongue (big sliver sticker)?  Our was Jan/2018.
cheers