Dometic 3 way a DC power hog!

[steve whiteside]

I got my Grandby last Friday. I have 2 ea 70-75 amp hour batteries. That fridge/freezer will pull those two batteries down from an over night full charge to 11.9v in about 3 hours. And that is with nothing in the fridge!

Does anyone else have this fridge? Is that what you experienced too?? The dealer says it is normal.

Steve

 

[MarkBC]

Running a "3-way" (aka absorption refrigerator) on DC doesn't work well at all. The only time it's recommended is when driving and with the truck charging the camper battery while driving. But even that doesn't work well.
If you're parked/camping, propane is best for the fridge...or maybe AC power, if you have it.

 

[rando]

This is normal for a 3-way fridge. They are really designed to run on propane or shore power. If you want to run on batteries you need a 2-way fridge.

 

[steve whiteside]

This is normal for a 3-way fridge. They are really designed to run on propane or shore power. If you want to run on batteries you need a 2-way fridge.

Now you tell me! haha.

It does seem to easily kick over to gas, which is a good thing. I guess when driving I will be putting more 12v into the batteries from the truck alternator. Doesn't anyone know how many amps will go through the 12v charging system built into FWC?

Steve

 

[MarkBC]

Ideally you would start with the fridge already cold (by propane or AC) before driving with it on DC. Just use DC to maintain the cool (while driving).

 

[57Pan]

Remember to switch back to propane or shore power when you stop. I have forgotten when stopping to visit a friend for a few hours and ran my battery down.

 

[DarinH]

It will help a lot to have your frig already cold and ALL your batteries (truck and camper) fully charged, before you leave home. The truck battery and alternator will struggle to provide enough power for the frig, and charge the camper batteries simultaneously.

 

[DarinH]

...also, if your have a little time (like an hour or 2), this thread is very informative on battery and solar power in FWC:

https://www.wanderthewest.com/forum/index.php?/topic/13230-I-need-more-power-Scotty!

 

[Beach]

Unless plugged into shore power, my fridge stays on propane. It'll run on propane(20 lb tank) minimum 2 weeks depending on ambient temp. Some folks here have had problems with the flame blowing out while driving but I've never had that problem. Just remember if you use propane while driving and you go into a store or stop for lunch while driving you need to find a level parking spot.

 

[larryqp]

Also if running on propane, remember to turn it off before fueling, or parking next to some one fueling.

 

[OregonOzzy]

Here is another thread with details you may be interested in re: usage, temps and current. https://www.wanderthewest.com/forum/topic/20438-dometic-3-way-fridge-temps/

On my 3-way I measured a 10.1Amp draw pretty consistently while on 12V. As others have noted, we use 12V while driving (via a Renogy DC-DC set up) and switch to propane at camp.

 

[steve whiteside]

It will help a lot to have your frig already cold and ALL your batteries (truck and camper) fully charged, before you leave home. The truck battery and alternator will struggle to provide enough power for the frig, and charge the camper batteries simultaneously.

Im surprised that my truck alternator won't provide more than enough power to provide 2x or even 3x power to charge my house batteries and run the fridge. What you all don't know is that I have a Goal zero 3000 that I plan to charge while driving too. It pulls 300-400watts from the truck. I ran a separate charge cable from the truck to the inside of the Grandby the other day. Steve

 

[steve whiteside]

Also if running on propane, remember to turn it off before fueling, or parking next to some one fueling.

haha good idea!

 

[steve whiteside]

Here is another thread with details you may be interested in re: usage, temps and current. https://www.wanderthewest.com/forum/topic/20438-dometic-3-way-fridge-temps/

On my 3-way I measured a 10.1Amp draw pretty consistently while on 12V. As others have noted, we use 12V while driving (via a Renogy DC-DC set up) and switch to propane at camp.

Perfect, thanks. I expect to learn a lot on this trip. Im taking one of those little truck starter lithium packs (for emergency starting) and also will be charging the house batteries and the Goal Zero off of a 1600w generator- when not driving.

 

[steve whiteside]

Here is another thread with details you may be interested in re: usage, temps and current. https://www.wanderthewest.com/forum/topic/20438-dometic-3-way-fridge-temps/

On my 3-way I measured a 10.1Amp draw pretty consistently while on 12V. As others have noted, we use 12V while driving (via a Renogy DC-DC set up) and switch to propane at camp.

Great info thanks.

 

[patrkbukly]

I also have a Granby (2016) and also have 2 batteries and also HAD the frig they come with.
I could only use it as an ice chest holder otherwise useless from an off grid power standpoint.

Save yourself time and frustration and go buy the Dometic CFX28 top load. Pulls I think .76amps per hour.
I have one panel and never make less than my setup uses now which is a game changer. Now I am truly off grid and stay out until I run out of water. Propane and eletric will go far further.

Discussion with Stan at FWC while in Flagstaff last year helped me make my decision. He is great. Really knows his stuff and is very practical and simple when it comes to solutions.

 

[Vic Harder]

Im surprised that my truck alternator won't provide more than enough power to provide 2x or even 3x power to charge my house batteries and run the fridge. What you all don't know is that I have a Goal zero 3000 that I plan to charge while driving too. It pulls 300-400watts from the truck. I ran a separate charge cable from the truck to the inside of the Grandby the other day. Steve

Upgrading the wires is a good idea. Is the GoalZero in the camper or in the truck? 300-400w is a goodly amount of juice. The wiring to the camper is bascially RV grade 14-12 gauge wire which will carry 30A, but not with out considerable voltage loss. That voltage loss is critical in terms of being able to charge your camper batteries or keep up with the 10A draw of a 3 way fridge.

 

[steve whiteside]

The goal zero is in the camper on the floor. The thick Goal zero charge cable runs from the truck batteries into the bed of the truck, then enters the camper via the turnbuckle opening. My plan is to start with everything full and charged. Eventually I will be in the situation where the truck batteries/alternator are pushing 12v to both the Dometic fridge and my goal zero. If there is not enough juice to go around it will be interesting.

I have 2 things to mitigate a serious draw down of the truck batteries, camper batteries, and the goal zero. 1) the 1600w generator and 2) the lithium emergency power pack.

I leave on Friday for 3 week shake down cruise in Baja.

Steve

 

[steve whiteside]

I also have a Granby (2016) and also have 2 batteries and also HAD the frig they come with.
I could only use it as an ice chest holder otherwise useless from an off grid power standpoint.

Save yourself time and frustration and go buy the Dometic CFX28 top load. Pulls I think .76amps per hour.
I have one panel and never make less than my setup uses now which is a game changer. Now I am truly off grid and stay out until I run out of water. Propane and eletric will go far further.

Discussion with Stan at FWC while in Flagstaff last year helped me make my decision. He is great. Really knows his stuff and is very practical and simple when it comes to solutions.

Your first fridge could run off of propane too? Was it a big power draw with propane as well as 12v?

 

[Wandering Sagebrush]

Steve, a refer on propane has very little DC draw.