LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[mitiempo]

It's hard to beat Engel's power usage.

.7 amps average as a fridge. That's 17 AH each 24 hours @ 77 Fahrenheit ambient.

[s/v Jedi]

Originally Posted by mitiempo

It's hard to beat Engel's power usage.

.7 amps average as a fridge. That's 17 AH each 24 hours @ 77 Fahrenheit ambient.

Energy consumption is not determined by compressor amperage, variations between compressors are very small; it is determined by insulation performance of the box. The Snomaster Expedition has 2.75” insulation and iirc the Engel has 2”.

I checked on performance figures. Engel does not have a 95 liter box, the largest I found is 80 liter. It has a 42W compressor, while the Snomaster has a 66W compressor. The Engel can not keep the recommended -18 degrees Celsius temperature at tropical 35 degrees ambient, at which point the compressor runs 100% of the time and the box temperature goes up to -13 degrees and consuming 80Ah per 24h (which is more than 1kWh). I added the test results as published by Engel themselves.

[mitiempo]

Originally Posted by s/v Jedi

Energy consumption is not determined by compressor amperage, variations between compressors are very small; it is determined by insulation performance of the box. The Snomaster Expedition has 2.75” insulation and iirc the Engel has 2”.

Compressor amperage and box insulation are both important. Most units use the typical Dan Foss compressor. Engel uses a very different much more efficient compressor design - inique to them.

My 40 quart Engel is very efficient. I have used it continuously for a decade.

[PaulCrawhorn]

Apples and oranges must be eliminated when comparing running efficiency.

Never mind compressor insulation etc those are besides the point, Ah per 24hrs is the only metric that really counts

Volume and actual contents must be the same.

Freezer usage makes for a HUGE increase over normal refrigeration. Ambient and actual internal temp (not target setting) must both be held constant to be comparable.

[newhaul]

Originally Posted by mitiempo

Compressor amperage and box insulation are both important. Most units use the typical Dan Foss compressor. Engel uses a very different much more efficient compressor design - inique to them.

My 40 quart Engel is very efficient. I have used it continuously for a decade.

Actually the swing compressor is not unique to the Engel.

[s/v Jedi]

Originally Posted by newhaul

Actually the swing compressor is not unique to the Engel.

I think the swing compressor is great. The Snomaster does not have a Danfoss compressor either, they have a custom unit but not anything like the swing compressor.

The point I made above, incl. graphs that support my case, is that the Engel boxes are not rated for use a freezer in the tropics, while the Snomaster specifically is. The Snomaster is an African product, targeting use with overlanding (4-wheel safari camping) in Africa and for that reason has 70mm insulation, which is much more than the competition has.
Also, where Engel has a construction from galvanized steel, Snomaster is stainless steel, so much better suited for use aboard cruising yachts, especially in the tropics.

About consumption figures for fridge and freezer: I did not record numbers for use as fridge because they are meaningless: yes they are very low compared to freezer, but in actual use aboard, the fridge will consume as much as the freezer. The reason is that it is opened so often, plus new, warm items are put in all the time. This is why static testing has no value.

[newhaul]

Originally Posted by s/v Jedi

I think the swing compressor is great. The Snomaster does not have a Danfoss compressor either, they have a custom unit but not anything like the swing compressor.

The point I made above, incl. graphs that support my case, is that the Engel boxes are not rated for use a freezer in the tropics, while the Snomaster specifically is. The Snomaster is an African product, targeting use with overlanding (4-wheel safari camping) in Africa and for that reason has 70mm insulation, which is much more than the competition has.
Also, where Engel has a construction from galvanized steel, Snomaster is stainless steel, so much better suited for use aboard cruising yachts, especially in the tropics.

About consumption figures for fridge and freezer: I did not record numbers for use as fridge because they are meaningless: yes they are very low compared to freezer, but in actual use aboard, the fridge will consume as much as the freezer. The reason is that it is opened so often, plus new, warm items are put in all the time. This is why static testing has no value.

That sounds like a great unit but on a 29 ft there just isn't room hence the ice box conversion with the technautics unit . I really like them . Have installed a few and had a couple on my bigger boats. Somewhere on here I even did a post in a refer thread showing my real world power usages just don't recall where . It was several years ago .

[rgleason]

Refr thread in LFP? Novel. Our ozifridge has Danfoss variable speed. Wish it were more powerful for when engine is running. Uses 4.2a to 7a has engine power mode. Small boat= custom box. Has air and domestic water exchanger (turned on for power mode). Uses about 24-30 amps/day after plate is drawn down to -6c . Cycles infrequently. Would like to rebuild box though. Newhaul where is your rebuild thread? Was that cryogel dangerous/hard to work with? Nano particles all over boat? Respirators used? Thanks

[newhaul]

Originally Posted by rgleason

Refr thread in LFP? Novel. Our ozifridge has Danfoss variable speed. Wish it were more powerful for when engine is running. Uses 4.2a to 7a has engine power mode. Small boat= custom box. Has air and domestic water exchanger (turned on for power mode). Uses about 24-30 amps/day after plate is drawn down to -6c . Cycles infrequently. Would like to rebuild box though. Newhaul where is your rebuild thread? Was that cryogel dangerous/hard to work with? Nano particles all over boat? Respirators used? Thanks

After over 500 pages wander is kind of expected
Here is my thread and link to start of refrigeration rebuild part of refit
https://www.cruisersforum.com/forums...ml#post3610051

Cryogel is non toxic but dusty real fine particulates wear a good dust maks and try to do as little as possible inside the cabin . Do all cutting you can with a breeze blowing dust away from you . When it's all done you will still need to dust everything on the boat the dust goes everywhere.

[mitiempo]

Originally Posted by s/v Jedi

Also, where Engel has a construction from galvanized steel, Snomaster is stainless steel, so much better suited for use aboard cruising yachts, especially in the tropics.

No galvanized steel on mine.

[newhaul]

Originally Posted by mitiempo

No galvanized steel on mine.

Dang that's expensive . that alone would add 30% to my boats total cost .

https://www.amazon.com/Engel-Portabl...23554861&psc=1
But it does look real nice. Where do I put it ?
63 Columbia defender.

[AKA-None]

Originally Posted by s/v Jedi

The document is actually good and states 600Wh… I have given up telling people that W is for power and Wh is for energy; they just don’t get it

That’s ok, Stu will remind people

[s/v Jedi]

Originally Posted by mitiempo

No galvanized steel on mine.

Yes that is the only marine rated unit Engel has. But it is only 40 quarts while the Snomaster I linked is 100 quarts which is 2.5 times as big.

Attached the specs for this unit. The MR40F, at coldest thermostat setting, can still not hold recommended freezer temperature in tropical conditions, resulting in 100% duty cycle at -14 degrees Celsius.

Note that it does qualify for a fridge in the tropics: at 4 degrees C with a 49% duty cycle.

In short: in the tropics this is a fridge, not a freezer.

[Simi 60]

Originally Posted by newhaul

Dang that's expensive . that alone would add 30% to my boats total cost .

https://www.amazon.com/Engel-Portabl...23554861&psc=1
But it does look real nice. Where do I put it ?
63 Columbia defender.

That 40 litre engel is about the same price as our 240v 2 door 550 litre fridge freezer

We'd need 13.7 engels to match the internal space

Which do you think uses more power on a/litre of cooling basis?

[rslifkin]

Originally Posted by Simi 60

That 40 litre engel is about the same price as our 240v 2 door 550 litre fridge freezer

We'd need 13.7 engels to match the internal space

Which do you think uses more power on a/litre of cooling basis?

Bigger units should be more efficient due to less surface area relative to volume. But of course, depending on your needs and the boat, there's always a limit to what you can carry. And a dedicated deep freeze only needs to be so big for most people.