Engel Power draw as a freezer

Hi Bob,
105AH Full River in the Prado.
210 AH in the camper which has an 80l Engel upright.

Phantom,
I'd be looking at replacing the Full River with something from the vast array of lithiums. For same weight as the 105, you could fit a 150-200Ah lithium which would give you 3-4 times the output of the Full River. As well as Enerdrive & DCS, check out Lithium Battery Wholesalers on Facebook. Good batteries at a good price, with good discharge rates...............and usually freight free.

Bob

If your Waeco only used ~17Ah in a week Kazza it's one in a billion. Presume that was the daily draw or am I having another Omicron moment (distinctly possible ;-) )?

The numbers were read from the display and entered into the spreadsheet at the end of a week.

This was done back in 2014 so my memory is a bit fuzzy after 8 years.

The specs for those "watt meters" indicate the Ah range of 0-65.
It therefore seems possible that the Ah display has "rolled over" several times so the true Ah used after a week would be (n * 65) + 28.8 where n could be 1, 2, 3 ... etc

Specifications

Voltage: 0V-12V-24V-36V-48V-60V @ 0.01V
Current: 0-50A @ 0.01A
Current Peak: 0-100A @ 0.01A (Short periods)
Charge: 0-65Ah @ 0.001Ah
Power: 0-6554W @ 0.1W
Energy: 0-6554Wh @ 0.1Wh

Ken

Hi kgarn.
Yes mate, you are correct.
What I don't know is the duty cycling of the Engel. Current draw when it is running is around 2.7 A.
It is a dedicated battery for the fridge in the car.

Hi qldcamper,
We’ve always done as you’ve suggested and just trying this out before our next extended trip. We did a 5 month trip last year from Vic to Cape York, stocking up every couple of weeks, staying in a van park and vac sealing and freezing before putting in the bottom of the Engel. This did work out well but gets kind of expensive at times.
This trip, we’ve filled the Engel up with 5 + weeks worth of meals as a trial.
Appreciate your reply.

Thanks George,
For all our previous trips over the last 6 years with the same set up, we’ve had the Engel set on 0 and no trouble keeping the batteries topped up, even on overcast days.
Think I'm asking too much of our current set up.

G’Day George

Reckon I would be checking your system with those figures.

If your lithium battery set up is at 12.7v at the end of the day it would be at around 15%, in fact bordering on to low. An AGM at 12.7v would be pretty full.

Regards

TrevorDavid

That may be so Trevor, however your AGM would have dropped below 12.7 volts at about 70% SOC, probably several hours before the LiFePo4 battery even dropped below 13 volts.

Macca.

Yes Macca true

But I was not suggesting which is better AGM or Lithium, entirely different debate. I was merely pointing out the fact that if he has Lithium battery/ batteries at 12.7 v they are not fully charged as he was thinking .

Just in case you’re wondering, I use Lithium.

Regards

TrevorDavid

Thanks for your comments, guys.

My lithium battery is lithium MNC, not LifePO4. It is a Nomad V5.

The manual says it is fully charged at 12.7V, which is when the charger goes to float (that's another story) when it's on a mains charger.

George_M

Thanks for the clarification George. They are not the type of Lithium batteries that I would choose, but as long as you are happy with them, and they continue to give you reliable and safe service.

Macca.

G’day George,
We don’t really need to store that much, just trying it out as a freezer to see how it goes as I’ve read about some people that do this.
Looking primarily storing at meat, fish, bread, icecream (??) pre cooked meals - fried rice, spaghetti, etc. We carry a Vacuum Sealer with us so we can seal food along the way.
Solar panels are 2 x 120 W Projecta folding blankets and will put out a total of 15 A on a sunny day. We have a 3rd panel that we take as well to use if needed plus another 2 back at home.
We’re pretty much full time on the road and we are just looking at the viability of having the Engel as a freezer which is not looking good with our current set up.
What we have now does work.

Hi Macca,
What you’ve said seems pretty spot on and we always try and keep the fridge as full as possible.
Need re-think of our set up if we want to run it as a freezer.

"Firstly, is there anything in the fridge or is it empty? Air is not a good conductor of heat/cold, so fridges will cycle less if they are something inside them."

One of the members on here, possibly Allan B did a comprehensive test on that with one fridge full and one fridge empty and found almost zero difference in power use.

Cheers
Gazz

I expect that result would change significantly depending on ambient temp and the number of times the fridge was opened Gazz.

G'day Bazooka

I will try and find the post when time permits but from memory that was all taken into consideration in the experiment.

Cheers
Gazz

Found it, but yet to read it, Gazz.

Allan's Myth Buster

Allan's experiment wasn't all "hot air" Gazz but I'm sure he wouldn't mind me saying that it wouldn't exactly pass scientific muster either. He did arrive at the conclusion usually mentioned as the big issue - the transfer of hot and cold air on opening. If bubble wrap reduced power use then we could likely expect that a fridge full of cold items might do something similar, moreso in hotter conditions.

There are really cheap units such as this one which will give you current draw, instantaneous Watts and (resettable) cumulative Wh consumption. They are actually quite good accuracy, having checked them against my other instruments.

I'm suggesting them to measure fridge-freezer consumption, NOT battery ins/outs as they are only rated to 20A. But if you want to calculate the Ah drawn from the battery, you have V and Wh so it's primary school division to find.

I did a similar-ish test on my 57L upright Engel (same running gear as 40L) set at the coldest setting and mine used 49Ah so a similar result.

My 22l "Brass Monkey" fridge/freezer uses ~ 52Ah per day operated at -18C and full of food.
I also note that it produces a lot of condensation on the outside walls if the humidity is high which would seem to indicate insulation could be better.

Ken

Why freeze? Quite simple. How do you bait fresh for fishing when camped for a week or longer. How do you keep you catch fresh to take home? Bread also freezes well and wont stay fresh otherwise.

Hi Bigfish

We aren't usually lucky to catch enough to take home :-)
But seriously, bait, vac packed, cast net on the day or pots. So we have no need to freeze this.
Bread, never going to happen, bit like ice cream. Needs minus 20c and getting that in the back of a 4x4 in the Top End is a REAL ask. But hey, each to their own.
Many people get their meat vac packed and then try to keep it frozen whilst traveling................
Can't see the point, but again, folks want the hassle of that then that's up to them.

Cheers
Lyndon

Lyndon. I live in FNQ and always travel with a freezer. Milk , bread and bait as well as meat stays frozen no worries at -18 in my fridges. Have camped for several weeks at a time in 37 + days and fridges work fine. Spent 20 years in Darwin and Gove so know the area well. Visited dozens of remote aboriginal communities via chopper, light plane or 4wd. I actually found it easier to just buy the food, freeze it and then eat when ready. Dont bother with the cryvac anymore. Also as I tend to be a reasonable fisherman I manage to always bring a few fillets home and freezing is the only way to do this. As you say..each to their own for me its handy having freezer on site. Cheers.

Cheers Captain,
I’ve dropped the Engel back to -1 and now have no problems with it keeping up, even on overcast days.
If I was to use it as a dedicated freezer in the future, then I would go lithium with a 200w solar panel on the roof and a portable as a back up for when parked in the shade.
With ambient temp of 25C during the day and 10C overnight, it’s using average around 30 per 24 hour

Hi Phantom and Captain.

-1 is not considered to be an appropriate temperature for a freezer, very easy for it to periodically slip into the positive temperature range and back to negative again. This is a recipe for food spoilage leading to possible gastric problems.

Food Standards Australia recommends -18 for frozen food, and +4 for refrigerated food. These temperature recommendations are there for a reason. Now obviously there is some “overkill” safety built into these temperatures, and you can safely get away with a higher freezer temperature, but -1 is definitely not a good number.

Also, depending on a couple of things, a 40 Ltr. Compressor fridge is likely to draw around 40 to 50 amps over a 12 hour period, so overnight, you could see your 100 amp battery down to 50% SOC by the morning. Not usually a problem with a LiFePo4 battery, but certainly could be with an AGM battery. So it is no wonder your battery is pretty much flat when trying to run two fridges overnight. A second 100 amp battery will help, particularly if both are LiFePo4 batteries, but you need more solar capacity if you intend remaining stationary for any length of time.

A good rule of thumb is that for every battery amp you have, you need double the watts of solar capacity.

Macca.

Thanks Macca,
Appreciate the feedback.
All our food is vacuum sealed so we’ve dropped the temp. back to just use as a fridge, not a freezer. This was a trial before our next extended trip.