Adding cooler to coolbox

ghostlymoron

ghostlymoron

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When I chartered a boat in Greece, the coolbox was fitted with a cooling element and compressor. It was wired so that it would only work when the engine was running. I am wondering whether this system is a good idea as it would avoid the enormous drain on batteries associated with a 'run at anytime' system. My main use for a fridge would be to keep milk fresh and butter. If the coolbox were well insulated, would an occasional blast meet my requirements?
PS I don't want to start another thread on dried milk.
 
ghostlymoron said:
When I chartered a boat in Greece, the coolbox was fitted with a cooling element and compressor. It was wired so that it would only work when the engine was running. I am wondering whether this system is a good idea as it would avoid the enormous drain on batteries associated with a 'run at anytime' system. My main use for a fridge would be to keep milk fresh and butter. If the coolbox were well insulated, would an occasional blast meet my requirements?
PS I don't want to start another thread on dried milk.
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Fit a Fridgemate switch, sneses when engine charging or shore power connected and runs, also has 2 hr override on battery only. http://www.jwmarine.co.uk/
 
and + 1.
Not familiar with new installations, but time ago there were those "holding plates" (if that's a name) with engine-driven compressor. The plate got 'frozen" and then kept the freezer for a day or two, as for coolbox it stayed cool for longer, even 4 days. Also can be used with electric. Such system is less energy-efficient IIRC, but then better for taking advantage of surplus energy when available. Might be this was the system on the boat.
 
The best solution for intermittent running is a "eutectic plate" system. The cooling element in the fridge includes a reservoir of some special chemical that, loosely speaking, holds coldness. So you can pump lots of extra coldness into the plate while the engine is running, for it to come out again over the course of the day and keep the box cool (these explanations will drive physicists wild, but I hope the point is clear :) ). Americans tend to use them more than us, with the compressor driven by a belt off the engine instead of electrically.

No idea as to costs and quite possibly overkill for keeping a pint of a milk fresh, but I thought worth a mention.

EDIT: I seem to be describing the same thing as Rossy.

Pete
 
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Stork_III said:
Fridgemate is £45 complete why bother with bits and pieces.
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This is the "Practical Boat Owner" forum, it's supposed to be about getting good value solutions. It's OK for you modern Hallberg Rassy owners to say it's only £45, but some of us have to watch the pennies! ;)
 
pvb said:
This is the "Practical Boat Owner" forum, it's supposed to be about getting good value solutions. It's OK for you modern Hallberg Rassy owners to say it's only £45, but some of us have to watch the pennies! ;)
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No need for even a VSR, then - just an ordinary relay with the coil connected to the engine panel circuit. I have exactly this to turn my steaming light on and off automatically; no reason it couldn't run the fridge instead as long as a suitably rated relay was chosen, and I bet it wouldn't cost £35 :)

Pete
 
prv said:
No need for even a VSR, then - just an ordinary relay with the coil connected to the engine panel circuit. I have exactly this to turn my steaming light on and off automatically; no reason it couldn't run the fridge instead as long as a suitably rated relay was chosen, and I bet it wouldn't cost £35
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I thought of suggesting that, but it's the "connected to the engine panel circuit" bit which I thought most forumites might consider too complex.
 
pvb said:
I thought of suggesting that, but it's the "connected to the engine panel circuit" bit which I thought most forumites might consider too complex.
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Depends on the engine. Much to my disgust, the new Volvo on the new boat has a digital control system and you have to buy an optional kit to get a simple "12v when running" output. But I would expect a boat with a coolbox instead of a fridge to have a simple old lump whose panel is easy to scotchlock onto.

Pete
 
But then again this automatic for just 45 has an appeal to me, as this will run the fridge any time energy is available, for instance when solars or wind generator give a good charge.
Otherwise the cheapest way would be just manual switch to turn it on - after all engine is started manually anyway, isn't it ?
Btw - cold plate has some salt solution inside that gets frozen, with melting point below 0. Not that I remember exactly... It absorbs any heat from the coolbox same way as ice - by melting - until it's melted completely.
 
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pvb said:
This is the "Practical Boat Owner" forum, it's supposed to be about getting good value solutions. It's OK for you modern Hallberg Rassy owners to say it's only £45, but some of us have to watch the pennies! ;)
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Having bought the modern Hallberg Rassy, some of us have to watch the pennies with microscopes.

Good tip is to put the freezer blocks, you brought in the coolbag with the food, into the icebox, refreeze when fridge working, will keep things cooler forlonger when fridge goes off.
 
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