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

[Dodgey]

I'm very tempted to buy one of the fridges from Currys and an inverter and test the current draw.... very tempted.... at least I'll then have the answer to a question that gets asked a LOT.

[g8dhe]

Also measure the noise it generates, that might be the critical factor ?

[Dodgey]

lol - I've got a Decibel meter, a voltage logger, a ammeter built into the solar regulator. I'm all set to go!

I'm not too worried about the noise - they run minimally at night, and I for one turn mine off when I go to bed. It hardly does anything overnight anyhow. I will measure it though.

I'm so going to have to do this.... I wonder how I can justify to myself having a spare, mini, fridge?

p.s. Geoff - any recommendations on a cheap inverter? Something just enough for the fridge. I'm struggling (call it lazy) to calculate Killowatt hours / per annum into Amphours

[g8dhe]

Just for a fridge alone its not a problem even allowing for the switch on surge of say worst case 5 Amps at 12 volts that's only 60 Watts, so a 100 Watt invertor would be fine and won't cane the battery either.

To get from KwHrs to AmpHrs you need to Multiply 1000 (Kw to Watts) and divide by 12v to convert Watts to Amps so you end up multiplying by 83.33

[Dodgey]

Got it - thanks - so the 113 Kwhr per annum fridge works out at about 1Amp draw on average (allowing for 24 hour, 365 day operation with thermostat) - sounds about right - allowing for it to be on about 25% of the time then that gives around 4 amps.

Gonna buy everything tomorrow - it'll allow me to demonstrate the figures on my website etc. - Someone in the locality can buy a cheap fridge off me once I'm done

[Waynem325]

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

I saw this but I'm restricted with its dimensions, hence the Caldura. The one from Currys would be more convenient with the ice box but until this moment I haven't thought I needed ice making/freezing facilities onboard?!

My van will remain unconverted so there is limited space where a fridge could 'live' whilst we're camping. I'm going to put it in the front cab and fabricate a removeable platform for it to sit on. The Caludra should be able to sit above the centre console and fit between the folded backrests of the 2 front seats. I was hoping to get out to measure and then order the fridge this weekend but not had chance yet!

Are the results in yet Dodgey? I wait with anticipation...

[c1rider]

I used a small domestic fridge in my race van. It was perfect except for the very high start-up current, even a 300W inverter baulked at it, so it was only any good on a hook-up. I also ran a 850W generator and it could just about manage the start current

[Waynem325]

But are the Caldura and Currys fridges (etc) that power hungry to need more than a 300w inverter?

[c1rider]

The rated power consumption is extremely low, so they need very little to keep going. It's the initial current to start the compressor that's the problem, and I don't see any way of knowing what that will be before you buy - unless you contact the manufacturer

[Observer]

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  

Hi, if you have three way why not take a spare bottle of gas and run it in a toilet/utility tent?
For longish trips on sites (often pub carparks), we use the Waeco 25 which is fitted inside the Bongo but put the bulk of our stuff (mainly beer) in the three way and leave it behind. The tent was only about £20 and is big enough for a portapotti, the big fridge (Combicool about 17" square) spare chairs and loads of other stuff and then it doubles as a shower (12v)
The three way not being a compressor job, is fine on 12v whilst we are travelling. Most times we don't bother paying for a hook up and so far have not been charged extra for the t/u tent but would expect to pay for a driveaway awning.

[Waynem325]

The rated power consumption is extremely low, so they need very little to keep going. It's the initial current to start the compressor that's the problem, and I don't see any way of knowing what that will be before you buy - unless you contact the manufacturer

Could be an expensive oversight!?! Would hate to dive in and buy one only to find its a no-go because of the start up surge - would a larger inverter cope, or would it be due to having a 12v source?

Hi, if you have three way why not take a spare bottle of gas and run it in a toilet/utility tent?

I did consider this option, which would be the cheaper option to go for (and possibly the one we go for whilst saving for a Waeco, if a domestic fridge is out of the question?) but would prefer to keep everything within the van for convenience & security.

Soooo many options!

[Dodgey]

I've not bought one yet as I need to find out about the start-up current. There are people using these fridges on inverters in the VW forums but as quick as they are to tell everyone that they work, then never seem to say which inverter. I've also read that pure sine inverters are important as it's what AC pump motors prefer.

What I can tell, is that you can add about an amp on in terms of consumption, and critically, another half amp permanent drain from the inverter, whether the fridge is on or not.

[Waynem325]

Pure Sine means lots of pennies and will turn a cheap idea into one costing 2 to 3 times more than originally planned. I have a cheap 300W inverter that a friend gave to me which works on low drain (Laptop/tablet/phone etc) devices, however, short of pulling the kitchen fridge into the garage (no chance!) I will have no way of knowing if it will take an assault from a compressor starting up.

I don't have it in front of me as I'm at work, but I seem to remember the Caldura tech specs mentioned 58W max for something, even though it runs at 13W. Would that indicate the 'power surge' at start up, or would it specifically say '...on start up max power would be 58W...'?

Anyway - we're Bongoing this weekend and I've resigned myself to the idea of taking the 3 way in the awning so I'm no longer in a mad rush to sort it out! Booooo!

[Waynem325]

The quest is finally over!!!

I've just bought one of these:

http://www.suremarineservice.com/c41.aspx

...for a truly bargainous £120!

It has a Danfoss compressor, which seems to get positive comments, and has just been re-gassed. Will get it next week....and then the testing can begin

Thanks for all comments and advice over the last few weeks - if anyone is interested I shall post back findings here?!

[g8dhe]

Good choice! The chest type don't drop all that nice cool air out when you open them! Plus you have a a reasonable "name" as to the quality (not something to rely on these days).