Freezer power consumption

Do a search and put in Cryovac.
Then make a decision.
You will get lots of info.

G'day Simon
I have made my own system and use an Engel 39l as fridge and a Waeco 29l as a freezer. Both are fed with heavy cable to prevent voltage drop and in 30 degree ambient temps they will easily flatten 225ah (in 2 batteries) down to require charging in 1 1/2 .
All depends on how much fresh air they get around them, I supply it with a computer fan, and also keep them covered with extra insulation when not using either fridge.

I use 160 w of solar and this keeps things going but with many variables it does prolong the charge life.
I think the only way to know what your fridges are using is measure the current draw of each so you know what they are drawing and then read a book and sit near them for an hour or two and jot down when each one starts and stops.

Do have them loaded and after they have settled into a pattern of operation in similar circumstance to what you will use them you will then have a record of each fridges typical run pattern.
Then you will be able to work out what solar, generator and or battery capacity needs.

Lots of people quote the usage of fridges and it is hard to know exactly what they are presenting and what it means. Some believe the manufacurers ratings/ some speak in Ah usage and some just say an amp rating. You can't work out anything without having the real information at your disposal.
So do your own tests and then use the info to formulate the power needs from the sources you might use.

My vehicle is white/his is balck, my fridges might use less power each day. Check it out.
Work on facts not hype.
Ross M

40L freezer will use around 50Ah. If short term storage and keep at -12C in reasonable ambient temperatures can keep it down to 40Ah.

40L fridge depending on ambient temperature averages 16Ah to 35Ah

We have a 25L deep freeze (DIY) with 150mm of urethane insulation plus a 130L fridge only with 85mm of urethane insulation. Both use remote Danfos BD35 compressors.
The freezer uses less power than the fridge.
Power consumption is about how good the insulation is.
Most commercial offerings are lousey.

Cheers,
Peter
OKA196 Motorhome

Like most power / fridge threads on this forum the terminology is mixed up and you won't get meaningful comparisons from the answers above. Some fridge manufacturers, like Waeco also get it wrong in some of their specs.

Firstly Simon, the consumption figures you are referring to are average AMPS, not Amp hours - ah.

Amp hours are a measure of CHARGE available or used, Ie the amount of capacity of a battery or the amount of average amps used over a specified period of time. Replies to your question have assumed a period of 1 hour, or 24 hours depending on the reply.

So the freezer you quote averages 3amps. That is, it would use 3ah over 1 hour or 72ah over 24 hours. Similarly the fridge averages 0.82Amps. Therefore it will use 0.82 AH in 1 hour or about 20AH in 24 hours.

On the battery side, 100AH would be able to run a fridge that uses an average of 3A for 33.3 hours, or a fridge that averages 0.82 Amps for about 115 hours before it is dead flat. BUT and there is a big BUT. You should not go below 50% capacity if you want to look after your battery so your 100AH battery will only last 16 hours for your freezer or 58 hours for the fridge.

People on here are quoting figures like 40ah or 80 ah etc because they are thinking in how many days will the fridge last between charges. This is a 24 hour figure even though they don't specify it.

Second, the current use is usually 3 - 4 times higher if you have a fridge on freeze. This applies to all fridges ( including the Primus) and is because of the extra energy required to remove the heat and hold it that way. Most portable fridges will run almost continuously when on freeze so they draw more current.

Thirdly, that leads to a pet hate of mine - permanent dual zone fridges. For example the Waeco 80 litre fridge which is half fridge and half freezer. It averages 3.5amps all the time. I'll bet the others are no better. The Waeco is actually a freezer that lets the fridge side get warm. ( and very warm at the other end of the fridge.)

The National Luna has a dual zone but you can set each zone separately. So if you use both zones as fridges then the current is low. But as soon as you use one as a freezer then the current goes up. I *think* some of the Primus ones have a similar set up, that could be why they are quoting 0.82amps - when both zones are used as a fridge. If you can set both zones temperature separately then that would be the one I would consider, though I think they also do one about 75l. I would go for that. You can elect to have 2 fridges ( cool for meat and beer, 8 degrees for dairy, veges etc).

The last point is, as others have suggested forget freezing altogether. There are only 2 reason to have a freezer. a)If you want ice cream, and b) for ice for your Bundy and coke. For food storage cryovacing is much more suited to camping. You don't have to choose dinner and defrost it in the morning, you can see what is in the packs, they are flexible so take up less space, and foods continue to marinade. Food will last 2 weeks for fish and chicken and 4 - 6 weeks for red meat.

I hope that helps and not further confuses you.