12v frig/freezer question

[RJ Howell]

I guess I'll be answering this fairly soon, but it's kinda driving me nuts..

I purchased a 12v frig/freezer (chest style) and awaiting delivery. Claim is 60watt run consumption (hoping on high..). I have no idea what the true duty cycle might be.. I've heard any where from 30/70, 50/50 tp 70/30 (on/off). And that's at what seem to be a 77° mostly sunny day (average I guess).

What are you folks seeing for consumption for a 24hr period (or whatever time you have recorded) in real life use? I really hoping for > a 40/60 duty cycle. in a 24hr period...

 

[Sparksalot]

A lot will depend on ambient temperature outside the fridge, plus how full you keep it.

 

[Flipper]

IMO first I would convert the watts to Amps. All your time will be measured in AH (amp hours,[minutes]) so divide the Watts by the voltage so 60 watts divided by 13volts is around 4.5 amps. That is your load in amps. Deep Cycle batteries are rated in minutes reserve time at a 25 A load. So for example let’s say your battery has a reserve of 90 minutes. So if you were drawing 5A you would divide 5A into 25A = 5 so then multiply the 90 minutes by 5 = that would give you 450 minutes of run time at a 5A load. Then time YOUR CYCLE and do the math from there. This is a variable so my time in Fl would not be the same as yours. I tried to keep this simple so you get and understanding of the math and time. Also never run your deepcycle down below 50% this will damage the battery. Any questions give me a shout. Glad to help.

 

[RJ Howell]

IMO first I would convert the watts to Amps. All your time will be measured in AH (amp hours,[minutes]) so divide the Watts by the voltage so 60 watts divided by 13volts is around 4.5 amps. That is your load in amps. Deep Cycle batteries are rated in minutes reserve time at a 25 A load. So for example let’s say your battery has a reserve of 90 minutes. So if you were drawing 5A you would divide 5A into 25A = 5 so then multiply the 90 minutes by 5 = that would give you 450 minutes of run time at a 5A load. Then time YOUR CYCLE and do the math from there. This is a variable so my time in Fl would not be the same as yours. I tried to keep this simple so you get and understanding of the math and time. Also never run your deepcycle down below 50% this will damage the battery. Any questions give me a shout. Glad to help.

"What are you folks seeing for consumption for a 24hr period (or whatever time you have recorded) in real life use? I really hoping for > a 40/60 duty cycle. in a 24hr period..."

How does yours run, at what temp are you basing it, at what setting did you run at and for how long did you measure?

 

[Renegade]

My ARB can go 32 hrs on a single GoalZero Lithum 400.

 

[kwill]

My ARB can go 32 hrs on a single GoalZero Lithum 400.

Which ARB? (Size?)

 

[Renegade]

Which ARB? (Size?)

50 qt

 

[leeloo]

bigger fridge might draw less depending on use. On camping I drink quite a lot of beer, but my fridge is small, I have room maybe for 6 beers only at least until I consume more of the food and make room. That means I grab a beer, put another warm one inside and so on. This does not help at all. If I had bigger fridge, the usage would be different. So it will draw more than advertised. Try to keep it in the shade, it helps. What the manufacturer advertises is a base line, like the fuel economy advertised for you vehicle. It will depend on the conditions and type of use. I added a small solar 100 W panel and I learned that even with a small panel, at sundown my AGM is full, while using the fridge and charging some phones/tablets. During the night is cooler, fridge is not opened so often, in the morning when it starts charging again, the AGM is still maybe at 90 % . I could stay like this for days with no issues.

 

[Flipper]

"What are you folks seeing for consumption for a 24hr period (or whatever time you have recorded) in real life use? I really hoping for > a 40/60 duty cycle. in a 24hr period..."

How does yours run, at what temp are you basing it, at what setting did you run at and for how long did you measure?

There are too many variables. How hot is out? Is the rig parked in the shade? Is it in a air conditioned rig while traveling. If I prefroze the food. How much food? How much liquid? How many time I open the lid. What temp do you set and store the food. Prefreezing helps the most. If I prefreeze everything it won’t even kick on for a day or two, on other days in Florida it runs constantly. The frozen or semi- frozen food that we are going to use that day I put in a cooler and let it thaw thru the day before dinner.

 

[RJ Howell]

My ARB can go 32 hrs on a single GoalZero Lithum 400.

Best I can tell, your Goal Zero is a 40ah unit. Sound right?

 

[RJ Howell]

There are too many variables. How hot is out? Is the rig parked in the shade? Is it in a air conditioned rig while traveling. If I prefroze the food. How much food? How much liquid? How many time I open the lid. What temp do you set and store the food. Prefreezing helps the most. If I prefreeze everything it won’t even kick on for a day or two, on other days in Florida it runs constantly. The frozen or semi- frozen food that we are going to use that day I put in a cooler and let it thaw thru the day before dinner.

Reason I ask "How you ran yours?" Eliminates all those variables....

 

[RJ Howell]

bigger fridge might draw less depending on use. On camping I drink quite a lot of beer, but my fridge is small, I have room maybe for 6 beers only at least until I consume more of the food and make room. That means I grab a beer, put another warm one inside and so on. This does not help at all. If I had bigger fridge, the usage would be different. So it will draw more than advertised. Try to keep it in the shade, it helps. What the manufacturer advertises is a base line, like the fuel economy advertised for you vehicle. It will depend on the conditions and type of use. I added a small solar 100 W panel and I learned that even with a small panel, at sundown my AGM is full, while using the fridge and charging some phones/tablets. During the night is cooler, fridge is not opened so often, in the morning when it starts charging again, the AGM is still maybe at 90 % . I could stay like this for days with no issues.

What size Frig and battery?

 

[leeloo]

I got a 35L Snomaster and I have a 105 AH AGM. 35l I think is more or less the same in US quarts.. about 37 quarts. In normal use, even on a very hot day it should draw no more than 2 amp/h ( I am talking average with the on off thing ) Mine is a travel version so the insulation is not great, in a hot summer day I noticed it runs about half of time. Temp is set at 2 degrees celsius , about 35 F . I know for a fact that a better quality fridge like an Engel draws almost half of that, maybe 1.2 - 1.4 not 2 amps for sure .
It was cheaper than the full overland version, but not by much. 400 euro instead of 600 . The solar panel I got after one time i spent 2 days in the same spot, I got the AGM at 10.8 V.. so almost completely dead.
Knowing what I know now I would have gotten an Engel. You go cheap on the fridge than you see you need a bigger battery, you will need a solar panel, solar panel needs a mppt controller.. etc etc.. more weight more space lost .. and so on, and the result, you most likely spend the same or more ( in my case with the cost of solar + controler more ) .

 

[RJ Howell]

I got a 35L Snomaster and I have a 105 AH AGM. 35l I think is more or less the same in US quarts.. about 37 quarts. In normal use, even on a very hot day it should draw no more than 2 amp/h ( I am talking average with the on off thing ) Mine is a travel version so the insulation is not great, in a hot summer day I noticed it runs about half of time. Temp is set at 2 degrees celsius , about 35 F . I know for a fact that a better quality fridge like an Engel draws almost half of that, maybe 1.2 - 1.4 not 2 amps for sure .
It was cheaper than the full overland version, but not by much. 400 euro instead of 600 . The solar panel I got after one time i spent 2 days in the same spot, I got the AGM at 10.8 V.. so almost completely dead.
Knowing what I know now I would have gotten an Engel. You go cheap on the fridge than you see you need a bigger battery, you will need a solar panel, solar panel needs a mppt controller.. etc etc.. more weight more space lost .. and so on, and the result, you most likely spend the same or more ( in my case with the cost of solar + controler more ) .

Main issue with Engel (or other high end units) is the cost.. Comparison for e is a 64qt Engel is just under $1500! Yikes.. They still claim .07-2.8 amps consumption. That equal to a 15% to 60% on Duty Cycle for my Generic.. for a quarter of the price. Okay, the Engel will out live me, yet I'm old and the Generic probably will as well. LOL

I'm testing on 110 now to get a baseline. I'll switch over to my 60ah lithium tomorrow and give that a go.

Thank you for the responses!

 

[leeloo]

True.
My advice is test first. Maybe the AGM will be enough. If it does not hold, a small solar panel usually does the job. With the solar, if you get a portable one, not the fixed unit on the roof, I think is better. You can keep the car in the shade and the panel in optimum position non stop. So you can get away with a much smaller unit.
Regarding the fridge sometimes there are deals on them or a SH unit might popup . Like 2 months after I got my fridge, I saw a few units on amazon, re manufactured Engel with 2 years warranty, looking like new, just a bit more expensive than my Snomaster. but they go really quick when they have the right price..
Snomaster is considered good quality, and they are good. My light/travel version, has the same internals as a much more expensive full overland version, but the insulation on them sucks.. hence the lower price..and higher amp draw compared even with the full overland version of the 40L snomaster..

 

[Flipper]

Reason I ask "How you ran yours?" Eliminates all those variables....

If I prefreeze and pack it well and use it for food storage only, 90 degrees out, truck in the shade. It’s dosent start to cycle until day 2, while food slow thaws in fridge, the cycle is probably 10/90 after several days , 70/ 30 with regular thawed food.