Low Consumption Fridge On A Budget

[MtB]

Thanks for all the responses guys. When I run this old Electrolux on 240 with my 1700w inverter, it flattens the batteries before it barely gets cold. I know I need new batteries before winter but they ain't that bad. Would one of those cheap argos fridges really perform much better than the old Electrolux? I don't really fancy leaving the inverter on constantly

 

 

Yes.

 

Or why not run yours on gas, as it is designed to do?

[Tony Brooks]

Suggested yonks ago and rejected by the OP. I suspect he wants another "magic switch" answer that involves little learning and work.

Edited July 2, 2015 by Tony Brooks

[smileypete]

Suggested yonks ago and rejected by the OP. I suspect he wants another "magic switch" answer that involves little learning and work.

 

I think it's a little unfair to single out the OP, everyone is like that in some way really.

 

Maybe the OP would like to know whether the solar and inverter is up to running a mains fridge, without having to buy one and find out the hard way - or not hopefully.

 

Best I can think of, a reasonable 'empirical' (suck it and see) way would connect a 15w light bulb to the inverter and leave it on 24/7 to simulate the approx load of a fridge and see how the batts cope.

 

Just a 15w pygmy bulb with a standard bayonet (BC) cap, plugged into a table lamp would do it.

 

cheers, Pete.

~smpt~

Edited July 4, 2015 by smileypete

[Kyle]

Suggested yonks ago and rejected by the OP. I suspect he wants another "magic switch" answer that involves little learning and work.

My god. What a loser, middle aged old troll you are. why do you provoke people online whilst sitting on your arse behind a computer screen? Does it make you feel knowledgable and superior? You know nothing about me, my life, or how hard I work

Edited July 4, 2015 by Kyle

[Tony Brooks]

I am not going to be provoked by your outburst - seem to me I hit a nerve.

 

You have had several suggestions, some from more than one person, and for some reason you rather than looking into them and doing a bit of research you keep coming back with reasons why not and more questions. Personally I get fed up with trying to help people like you and essentially having my experience hurled back in my face.

 

You have been advised:-

 

1. Run it on gas because will have a zero electrical load. (Twice)

 

2. Consider an A++ mains fridge running from an inverter. (At least twice).

 

3. Build your own unit in one of two ways although personally I do not think that will fit well with your topic title.

 

4. Be vary careful about "claims" for low consumption named in on-line adverts.

 

All of which by your posts you seem to have ignored.

 

The bottom line is that your 3 way fridge draws 8 amps at 12V ALL the time it is turned on so it is no wonder it flattens your batteries. Many Pelltier (semi-conductor) cool boxes/fridges also have no 12V thermostats and although they typically draw 3 to 4 amps they are doing that all the time. Also many have very limited cooling ability. Any fridge with a working thermostat, mains or 12V compressor, will draw far less from the batteries that your 3 way fridge. Exact how much less no-one can say because we have no data on your inverter so we can not guestimate the load demanded by the fridge plus inverter.

 

You are likely to get some replies that assure you a particular solution is the one you for you but often it is based on a single experience so needs treating with a bit of caution because your use may be very different and thus demand a slightly different solution.

 

If you are only interested in keeping dairy products a little fresher and longer that keeping them on a worktop then cutting a hole in the floor, removing ballast and building an open bottomed insulated top loading box on the base plate might suffice (a bit like the gas bottle idea that is based on good science). If you want cold drinks etc. then you probably do need a fridge of some sort but in the end it is your boat and only you know how you use it, how you charge your batteries and what you can afford so its your call.

 

Typically 12 V compressor fridges demand around 40 to 50 Ah per 24 hour period. If you run your engine every day this can be reduced somewhat (at a price) by the use of holding or cold plate technology but those fridges would certainly not fit your title.

 

I would agree that it can be difficult to find the actual consumption of mains fridges because the bumph sheets tend to give an annual consumption in kWh so you would need to convert that to watts hours, then divide by 10 to convert that to amps hours at 12V to include an 80% inverter efficiency. Finally divide that by 365 to find the Ah per day. If you are lucky a phone call or email to the manufacturer might give the actual consumption in amps so then multiply that by 10 to get amps at 12V (inc. 80% inverter efficiency) and multiply by 12 to give Ah per 24 hour period. However that 12 assumes the fridge runs for 50% of the day. An A++ one might well run less. A good top loader even less.

 

There is no simple answer. You need to understand the complications so you can make the best decision for you. IT may even turn out to be the product you first linked to as long as you can get written confirmation of its true consumption.

Edited July 4, 2015 by Tony Brooks

[smileypete]

Don't waste your breath on him Tony.

 

Won't get any more help from me, though an apology to Tony is definitely in order.

 

cheers, Pete.

~smpt~

[Tony Brooks]

Don't waste your breath on him Tony.

 

Won't get any more help from me, though an apology to Tony is definitely in order.

 

cheers, Pete.

~smpt~

 

Thanks Pete

 

Actually I would like to have worded my reply to MtBM a little more diplomatically but to say much the same.

 

I keep telling myself that for every one that appears (note appears) to be a plonker the forum helps many, many more genuine questioners so one should not give up. but increasingly I feel like doing a "Gibbo".

[Higgs]

My Shoreline 12v has been running off a 650w computer power supply unit non-stop for a year. The supply unit is rated at up to approx 35amp on the 12v side. The PSU runs cool and the fridge seems happy on it.

 

It was only a trial, until I have the time to connect the fridge up to the domestic batteries. But, as I have access to 240v shoreline, I'm in no hurry to connect to the batteries, at the moment. No idea how well the CPU setup would work with an inverter. It would probably need pure sine wave to work well. Can't really see any other problems. The PSU is very close to the fridge.

 

I hardly ever notice when the fridge cycle is on or off. Before, I used to have a mains fridge. The 12v fridge and setup is using less electricity.

Edited July 4, 2015 by Higgs

[Paul C]

 

 

No idea how well the CPU setup would work with an inverter. .

 

This bit doesn't seem right - running a 12V fridge by using an inverter to convert 12VDC to 230VAC, then using a (home made) power supply to convert 230VAC to 12VDC. I'd expect each stage will have an efficiency loss.

 

The rest doesn't seem right either - running a 12V fridge off a 230V supply for so long - the main advantage of a 12V fridge is that it runs........from 12V, so it can run from the boat's 12V electrical system without the need for an (possibly expensive) inverter. The main disadvantage of a 12V fridge is its cost over a similar 230VAC one.

[Tony Brooks]

I think that he is using the power supply to run the fridge off a shoreline (mains). Really not a lot different to running from a battery charger or the shoreline add on unit that does the same thing.

[Higgs]

 

This bit doesn't seem right - running a 12V fridge by using an inverter to convert 12VDC to 230VAC, then using a (home made) power supply to convert 230VAC to 12VDC. I'd expect each stage will have an efficiency loss.

 

The rest doesn't seem right either - running a 12V fridge off a 230V supply for so long - the main advantage of a 12V fridge is that it runs........from 12V, so it can run from the boat's 12V electrical system without the need for an (possibly expensive) inverter. The main disadvantage of a 12V fridge is its cost over a similar 230VAC one.

 

 

That all depends on whether there is a suitable cable connect over distance from the batteries to the fridge. On the subject of it not seeming right - it got the job done, under the circumstances, and the proof of the pudding is in the eating - it works fine. The setup is simple and effective. What more could you wish for? The PSU cost £26.00.

 

It is only another alternative. One that I wouldn't have used had I the correct wiring installed before the mains fridge died a sudden death, and, were it not for the fact that I had a 12v, never-been-used fridge, waiting in the wings. To add an inverter into the solution is only what could be used for people without mains, but who have an inverter and also do not have the correct wiring installed from fridge to batteries. Less than ideal, but would be a solution.

Edited July 4, 2015 by Higgs

[Phil Ambrose]

My god. What a loser, middle aged old troll you are. why do you provoke people online whilst sitting on your arse behind a computer screen? Does it make you feel knowledgable and superior? You know nothing about me, my life, or how hard I work

Tony is probably one of the most knowledgeable people on this forum and an apology from you is the least you can do.

Phil

[cereal tiller]

My god. What a loser, middle aged old troll you are. why do you provoke people online whilst sitting on your arse behind a computer screen? Does it make you feel knowledgable and superior? You know nothing about me, my life, or how hard I wor

Reported

[cuthound]

Don't waste your breath on him Tony.

 

Won't get any more help from me, though an apology to Tony is definitely in order.

 

cheers, Pete.

~smpt~

Seconded.

 

If we had to lose either Kyle or Tony from the forum I know who I would choose.

 

Kyle, if I were you I would apologise now if you expect to get much more help from this forum.

 

Edited for spelling.

Edited July 4, 2015 by cuthound

[Tony Brooks]

Please can we let this branch of the topic die. I could probably have put my observation better sop Kyle probably thinks he has a right to moan a bit.

 

I am only too well aware that many of us have good quality expertise in certain areas so it is not good to appear to single out individuals although its nice to know others seem to value some of my input.

 

Cheers all.

 

 

PS come to think of it I doubt there is much more of value that can be added to the thread so its up to Kyle to read, learn, and inwardly digest. Probably time to let the whole topic drop.

[Phil Ambrose]

Tony, you are definitely the bigger man.

Phil

[abraxus]

Finally, regarding the thermostat, it says that the new fridge I'm thinking of (the first one above) has on 12v "Electronic thermostat

Thermoelectric". Would that ensure its not on a constant drain?

I have the Waeco 40D as an overflow to my main fridge, and so can tell you that the thermostat only works on 240v, when it uses the compressor, where you can set whatever temp you like down to -15C. On 12v it runs in thermoeletric mode, without the thermostat, and cools to max 20 degrees below ambient.

 

Given that it consumes 48w on DC thermoelectric but runs permanently, compared to 65W when running the compressor on 240v, but only seems to run for about 30% of the time, it would appear better to run it continually on 240v from an inverter, as it would be colder and use less power.

 

It's actually a pretty good fridge, especially as it can also be used as a freezer if you like. I set the thermostat to 3C and the thermometer I put inside reads 2.8C, so it seems to work well. I use it mostly for keeping drinks icy cold, for which it's perfect. However, for a main fridge, for keeping food, I prefer a regular one, with shelves.

Edited July 9, 2015 by abraxus