Seeking advice for managing a freezer from people with real experience

Hi. I have 260w of solar power and 220 of ah batteries. Off this I run a 40lt Engel as
fridge and 80lt Engel as a freezer.We go out winter months WA goldfields. I will have
the 80lt cranked up while getting the sun and the freezer will be around -18. I monitor this in the arvo and when I start losing power input turn the freezer down to sort of fast idle.In the morning the freezer will have dropped to around -9, all contents are still
frozen. Batts have dropped to around 70% when sun starts recharging I turn the freezer back up. Just leave the 40lt on no1 setting.This gets us by and I only open the
freezer once a day.Been using this setup about 11yrs. Brian

Boobook
My fridges are 39LEngel as fridge and CDF35 "Wacko" 20 something Litres as freezer.
I never bother to turn up and down as the little bit of extra cool is only a few degrees difference but doing it does act as a buffer for a while. Not sure how much you really save there.
I found by adding additional insulation to both of the fridges they both use less than with the proprietary Insul bag many have. Factory unsulated bags are pretty useless I reckon. Good selling point though.

Except at times when we want to use either, there is also another additional layer of old sleeping bag over the two so air movement near the cool faces is then restricted and losses minimized.
A small solar panel, or main solar system power, is used to run a fan which constantly changes the air for the condensers so there is no recirc of heated ambient air near the fridges. That shortens run times too.
The covering of whatever insulation used is further enhanced by having a space blanket or silver paper sheet, shiny up, so it is reflecting radiant heat from though the roof and windows of the vehicle.

Doing this meant that the Waeco can actually freeze despite the claims it can go to -18, but in 30degree ambient it would barley freeze as the claimed 40 below capability was quickly negated unless suitable insulation made it all possible.
In STD trim the Waeco no way, and the Engel also found it hard to keep cool.

With the above insulation the fridges actually get to switch off.

G'day Boobook,

I ran a 50 litre Weaco in my car as a freezer last year during a three and a half month travel across the top. The temperatures were hot with lots of mid thirties and the car has just a 120 amp hour battery and 2 X 80 watt solar panels as well as being charged whilst driving. There was only one or two times I felt compelled to fire up the generator. The freezer had everything frozen rock solid so I was most impressed as I really had not expected that it would work that well.

I also need to point out that the freezer is located in the canopy and was never removed. Your set up should be more capable and I would suspect it should work OK.

Kind regards

G'day Boobook,

I run my car fridge almost exactly the same way. -19 when driving or on mains or gennie, -10 otherwise. All good. We cycle our food. Stuff at the top stays frozen, but not as deep frozen as stuff at the bottom, so the top is next to be used. I think the freezer pulls about 32Ah a day at -10.

Our power setup is similar, but our useage a bit different. Based on my experience with ours, I think you'll be ok.

We have 320Ah of batteries. Until recently we had 240W of portable solar and an MPPT regulator. (We have since added 200W of fixed solar on the roof but I'll leave that aside for the moment.)

We have a power-hungry hybrid camper with a 130L compressor fridge plus other electrical loads. On average in hot weather the fridge pulls about 48 Ah a day, maybe a bit less. Much less in cool weather.

When camped I run the car fridge (freezer) off the 320Ah camper system with its 240W of solar, so our combined fridge-freezer consumption is about 80Ah a day.

In good solar conditions (10 hours of clear sun) our portable 240 watts is more than adequate to supply the fridge-freezer load plus other loads if it is tracked to get the best sun. However, if ther is o solar we are good for only a day or two because I don't like to run the batteries much below 50%. Could last longer if I was prepared to go way below 50%, but I'm not. When that happens I start the gennie or drive.

We recently added 200W of roof solar, to compensate for less than ideal solar conditions. Since then we rarely use the gennie. On a recent 8 week trip Sydney, Cameron Corner, Strzelecki Tk, Wilpena, Clare, Eyre Peninsular, Western Vic and home we didn't use the gennie once for battery maintenance, only to run the aircon once at Arkaroola when it was 42 deg.

So, mate, interpreting our experience a bit I reckon you'll be ok, providing you only have the freezer, not another fridge and your other electrical loads are light.

Cheers

Boobook I have run a 80 litre waeco as a fridge freezer dual zone on -18 all over australia on 200ah of batteries have never had any problems but drive most days I have 120 watts of portable solar and a gennie for backup but on a recent trip perth to cape york and back did not use tthe gennie except to run the air con allthough it can get through 40amp/hr overnight in very hot weather
Cheers Steve

Boobook I have run a 80 litre waeco as a fridge freezer dual zone on -18 all over australia on 200ah of batteries have never had any problems but drive most days I have 120 watts of portable solar and a gennie for backup but on a recent trip perth to cape york and back did not use tthe gennie except to run the air con allthough it can get through 40amp/hr overnight in very hot weather
Cheers Steve

We run a 40lt as a fridge and a 20lt as a freezer. We have three 105AH Allrounder batteries in a one for car and crank and two in parallel for 4WD accessories. No solar and no generator. The winch is on the main and a 200 ampere Redarc isolator is in between the main and the two accessory batteries. We mostly travel and rarely camp more than two nights. We have not had an issue with the fridges nor have we fired up the car during those few stops.

However in saying that I am am not keen in pushing the two accessory batteries any further without a bit of charging.

Phil

Thanks to everyone who provided input.

I am in the middle of some testing and so far have the following results based on days 13 - 25 degrees average.

-I set the freezer to -18, it used 61Ah per day ( average of 2.6 amps)
-I freeze to -22 when the car is running, then -16 when rested it used about 48 AH in one day. ( though the day I did this test was hotter).
-If I reset the freezer to -22 when driving, it takes about 3 hours to get back to -22 degrees.

I am doing a few more tests and will provide feedback for others as I go. The same fridge uses 20AH per day as a fridge, so freezer power use is about triple.