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OzePete · 30-04-2018, 23:30

For those with a cyclic fridge with cabinet temperature reading thermostats, (most) you can very easily get better power economy at virtually no cost...
Simply coat the thermostats sensor probe end in silicon (non-acetic) then let it live in a small container of water inside your cabinet. A tall thin thingy say 1" diameter or thereabouts is best.

The water will slow the on- off cycles (it will now run longer and stay off longer) and best represent product temperature. Suggest setting digital controller at +4C and +2C for a fridge and if you are stuck in the dark ages with one of those vague 1 to 7 guesswork thermostats, then best to ditch it, spend $20 and get a digital, you will never look back!

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

Lazza · 01-05-2018, 02:47

Great idea - I'll get on to that

Where do I get one of these digital controller/thermostats for a BD50?? I'd love to get out of the dark ages!!

Big congrats too for the relocation & expansion

OzePete · 01-05-2018, 05:06

Quote:

Originally Posted by Lazza

Great idea - I'll get on to that

Where do I get one of these digital controller/thermostats for a BD50?? I'd love to get out of the dark ages!!

Big congrats too for the relocation & expansion

Thanks Lazza.
Your best bet is eBay ...
Look for an Elitech STC1000 AC DC 12V All-Purpose STC-1000 Digital Temperature Control/Controller Sensor AU $9.97. They come with the temperature probe and instructions.
If you end up with a 110-240VAC type, simply slip the cover off and bypass the little transformer.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

sailormed · 01-05-2018, 05:29

If you look up this thread «*Computer Fan for Refrigerator Cooling?*»
you will find another low cost solution to improve refrigerator efficiency. My installation improved efficiency for the freezer by more then 50% and for the fridge somewhat less. That is a lot of Amphours saved.
Boatyards do not seem interested in airflow engineering for fridge efficiency.

Maka · 01-05-2018, 12:37

Another option is to get a 12V refrigerator / Freezer for trucks and RVs. About $500 USD.
Freeze water bottles in it and rotate them in your boat fridge.
Eliminate conventional equipment in your fridge, there by creating more space.
Your fridge is now an ice box.
I have not done it yet but am seriously considering it.

bill99 · 01-05-2018, 16:39

Another tip given to me by a fridgeologist was that a fridge hates to try to cool air.
So wherever possible fill the empty space with bottles of water. I would fill the bottom of my icebox with water bottles and the food etc on top of that so there was no empty space. The compressor would then cycle on/off less using less power and becoming more efficient.

OzePete · 01-05-2018, 16:58

Quote:

Originally Posted by bill99

Another tip given to me by a fridgeologist was that a fridge hates to try to cool air.
So wherever possible fill the empty space with bottles of water. I would fill the bottom of my icebox with water bottles and the food etc on top of that so there was no empty space. The compressor would then cycle on/off less using less power and becoming more efficient.

That's correct Bill, the hardest thing to keep cold is air. It is too fluid. Also the refrigerated bottles of water act as a 'hold-over' although no where near to the extent that a eutectic system does, it still helps when topping up the cabinet with warm product.
And the earlier posters small cabinet circulation fan idea is a good energy saver also, as air movement puts more load on the cyclic evaporator plate thus increasing the evaporator pressure causing the compressor unit to be operating with a better COP (Co-efficiency of performance) or in plain speak more bang for your buck!

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

Aguabago · 01-05-2018, 21:33

Based on a tip in a boat cooking book, I fill the upper portion of the fridge and freezer with a space blanket. Works great.

Ray Perry · 01-05-2018, 23:35

A good idea is to make some shade cloth bags and fill them with bean bag filler. Make a few different sizes for different volumes. Just fill any spare space in your freezer/fridge. They DO work and are easy to clean with nappy detergent/powder.

john61ct · 02-05-2018, 08:05

Better if your 'space filler' material has thermal mass.

Water/ice being the cheapest and most useful example.

Buffers the cycling, acts as cheap eutectic storage, reduces AH per day consumption dramatically.

The lightweight examples above not so much, but better than nothing I suppose.

rabbi · 02-05-2018, 08:45

Quote:

Originally Posted by john61ct

Better if your 'space filler' material has thermal mass.

Water/ice being the cheapest and most useful example.

Buffers the cycling, acts as cheap eutectic storage, reduces AH per day consumption dramatically.

The lightweight examples above not so much, but better than nothing I suppose.

One thing that dramatically improved our refridgeration in both quality and energy consumption was to add a second fridge.

The original fridge is a front loading standard unit. Opened & closed too often to get at cold drinks during the day, and in the evening it was even worse for the beer.
If I added warm beer in the evening the fridge consumed tons of precious battery power. If I added too much warm beer the temperature would go way too high for hours.

The fridge had to work hard to cool down the drinks, and would create thick ice on the coldplate from condensation so required defrosting often (read: amp hours and unhappy wife).

So what to do?

The Lagoon 380 S2 comes standard with a large toploading insulated box under one cockpit seat. A danfoss fridge unit fits nicely in an empty space under the cooktop and the coolplate in box. I wired it to one of our solar chargers so it runs on excess solar power only.

That outside fridge has lots of thermal mass, as it typically contains a few boxes of beer and some water. It starts when there is surplus solar power, and runs continously until the sun goes down or the beer is about to freeze.

The result: drinks are ok in the morning, cold during the day, ice cold in the evening. I can restock drinks whenever I want, and they get cooled down as soon as there is sun. There is no food to go bad in case i restock too much beer at once.
And there is no power draw on the batteries because it only runs when there is too much solar power.

Now the original fridge is opened only a few times per day for food, consumes much less amphours than before especially at night, has much better temperature stability, and does no longer need frequent defrosting.
Now its the admiral's fridge.

The skipper's fridge has only one drawback: Its under the skipper's seat, so I have to get up to lift the cockpit seat and get another beer.

jamhass · 03-05-2018, 08:01

If a top-loading refer/freezer, place a yoga mat on top. helps seal air leaks around door, adds a bit of insulation, adds a non-slip surface. Saves a few ah.

If you are in a sunny place, and the box is against the hull, drape a towel, etc on the outside of the hull to shade the area. A couple more ah saved.

If too big a box, closed-cell foamboard (pink stuff from HD works great) can fill the bottom reducing volume and adding a bit more insulation. Easily removed, cleans up well.

sailor_ed · 03-05-2018, 09:49

OzePete

In the US on our eBay I find an ITC 1000 temp sensor/controller that seems to be similar to the controller you mention but the 12V units are all listed as 12VAC 50/60 Hz. Would I be able to use / adapt one of these? I would like to exit the stone age!