Battery drain help with 240v compressor fridge needed....

[Dodgey]

As an example, a coolmatic (waeco) 60 litre danfoss compressor fridge uses 3.6 amps when on, which is about 50% of the time on a hot day, and about 10%of the time at night (when it's cooler). That has a burst of around 4.5 amps when it fires up each time. You get around 2 days on a well charged, good condition 100Ah leisure battery.

They don't get much more efficient than that. I'm assuming the smaller Waeco fridges lose a little less, but as long as the box is insulated, and they all use the same compressor, they are going to be in the same ball park.

Based on that. At a guess, using a 240v fridge on an inverter, and assuming 25% loss on the inverter, you are looking at a day to a day and a half with one. Add solar and you are good to go longer

[scanner]

frozen milk/pees

I'll stay with a porta potti thanks.

[dom_e]

Frozen peas.....oops

[Waynem325]

Thanks for the replies!

I'm getting severely bogged down with this!
I was hoping there'd be an easy 'cheap solution' to finding a low power fridge?!?

I've put in too much time on this already, so maybe it's time I cut my losses and look at the Waeco market?
Dodgey - you inspired me to invest in solar energy (ever since your first solar related post asking what people would want from a solar-system etc) and the main reason I've gone ahead with it was so we could run a fridge for at least a full weekend and longer, and not have to worry about switching it off or running the engine etc.

I'm sure there is something out there that would tick the boxes I have, but if I continue looking for it I may well end up single?!!

Thanks for the input everyone. When I do finally make a purchase I shall post back here and let you know what I opted for.

[Waynem325]

In fact....hold that thought!

What about the Waeco B40 Hybrid? http://www.camperlands.co.uk/waeco-mobi ... ridge.html

This seems like the perfect solution!
12v supply whilst en-route, and then via an inverter upon arrival!

Now then, is a cheap £15 - £20 150W/200W inverter going to be okay? (Don't want/can't afford a pure sinewave)

(My head hurts!)

[Simon Jones]

Ok, so it runs on 12v as a fridge or if you run it on 240v it can also freeze. Unless you want to run it as a freezer, what is the point of converting 12v to 240v? Do you want something that big and heavy (21kg)?

[Dodgey]

That hybrid sounds like it will run like a cool box on 12v - so not the best compromise for £300. I say "sounds like" as they mention "20 degrees below ambient" which is typical of non-compressor fridges.

If I were in your position, I'd get on the VW forums, find out which 240v fridge they use with an inverter, and try it out. I'm sure we are talking about £100 ish plus a £20-£30 inverter.

[helen&tony]

Hi
I looked at those the other day...we're trying to find a 'fridge that will run in 40C. plus heat, but have eventually decided on a 3-way 'fridge and go camping in Spring and Autumn, when temperatures are in the 30s...So far the Dometic S2200 seems to be our best bet...would it suit you?
Cheers
Helen

[winchman]

That hybrid sounds like it will run like a cool box on 12v - so not the best compromise for £300. I say "sounds like" as they mention "20 degrees below ambient" which is typical of non-compressor fridges.

If I were in your position, I'd get on the VW forums, find out which 240v fridge they use with an inverter, and try it out. I'm sure we are talking about £100 ish plus a £20-£30 inverter.

Quite a few of them use the Dometic DS200 or DS300 as they are only 65w so a cheap Aldi 150w inverter will run one. Remember many of the cheap 240v fridges are compressor models so noisy and higher power drain especially on start up.
Bloke on forum occasionally sells them secondhand

[Waynem325]

Hi all,  
This should (hopefully?) be the last ask...

I think I've found the perfect short to medium term solution, and it won't cost a penny  assuming I'm right???
Whilst in the garage earlier I dug out the 3 way fridge we'd sell/replace for a compressor fridge to take a look at the product spec label. At 12 volts it runs at 6.1 amps, which is no better than the cool box, but at 240 volts it runs at 0.3 amps. I must be wrong, or I have missed something as that figure sounds more like a compressor fridge? Hopefully below is a pic of the label. If I were to use an inverter and run it at 240 volts then even with loss taken into account, and with a solar panel charging the depleting battery, won't this run for a good few days at the very least?  
 

It is big, and I may well remove one of the back seats to accommodate it, but it could work for us?
Then I can save up for a compressor fridge and be able to take my time looking at and choosing exactly what will suit our needs.  

Simples  

[Simon Jones]

If you notice, both the 12v and 240v ratings are 72 watt, so the power consumption is the same for both.

Watts = Volts x Amps, so you see that for the wattage to remain the same, the 20x increase from 12v to 240v will mean a corresponding 20x drop in current. The sticker confirms that: 6.1 A / 20 = 0.3 A (give or take one decimal place).

So, if you had a perfect loss-free inverter, you could run it on 240v and the total power consumption will be same as 12v. In reality an inverter is perhaps 80% efficient, so you would require more energy to go from 12v to 240v than if you just left it on 12v.

Have a read of this: http://www.campertrailers.org/3-way_fridge.htm

[Waynem325]

Curses!
Dammit Simon, you're right!
I was blinkered by the 0.3 and didn't even pay attention to the power!

Bugger!

Thanks for all suggestions too - I will look in more detail when I'm on my laptop - currently on my phone and it isn't the easiest, most practical thing for this forum

[Waynem325]

Well, after much deliberation I have finally decided upon buying this:

http://www.caldura.co.uk/products/refri ... n/ec35.htm

After viewing the operating instructions it has a max input power of 50W (Assume that's upon the compressor initially starting up?) and has an average power consumption of 0.3KWh/24hrs.
If my calculations are correct that makes it as near as damn it 1 amp? Which, even with inverter loss, should last a good couple of days, and especially with a solar panel topping up the batteries!

The potential of noise doesn't put me off, as I imagine during the day (when we're not really in the van) it won't be an issue, and if it proves to be too much overnight, like others - we'll just turn it off!
It's one of the most efficient domestic fridges I have seen, so we shall see if it cuts the mustard?!!

Probably ordering this weekend or early next week so watch this space!

[francophile1947]

Similar spec to this http://www.currys.co.uk/gbuk/household- ... s~12265384 but more than twice the price

[g8dhe]

And its 47l compared to 35l and has a an ice box.