compressor fridge

[Wildbill]

Thinking abut getting a compressor fridge do they swallow up battery power 12v
bill

 

[wiljoy]

They eat your power. If not on hook up you'll need extra power to keep it happy. Solar panels will help but possibly not all the time.

 

[cmcardle75]

They will clearly take a significant amount of 12V. However, if you design your 12V system correctly, this can be catered for. You do get significant advantages with a compressor fridge, such as not using any gas supplies, not requiring gas engineer servicing, greater reliability, an actual ability to cool things down, ability to use solar power, larger usable capacity for the same space taken, greater flexibility in location, no need to puncture the vehicle skin...

Just don't expect to off grid for a week with a 100Ah lead acid, no solar and a split charge relay. And if a pine needle dropping in the next field wakes you up, forget it.

You'll need at least one of: decent solar (and enough daylight to make it work), occasional electric hookup, a B2B (and enough driving to activate it), or a large lithium battery to last out your trip.

 

[CamperJack]

I'm thinking about getting a Dometic crx50 if I ever save up enough pennies. That has an "average consumption" of 40 watts. So at 12V that's about 3.3 amps.

As I understand it that isn't constant. It will turn on and off based on when it reaches the set temperature. So it changes.

But a compressor is supposed to be much more efficient than a 12V absorption type or a 240V household one.

 

[Richard n Ann]

Our compressor coolbox drops below 3 amps when it's been running a while. Standby consumption will be very low, just the LED display and microprocessor controller.

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[DBK]

Thinking abut getting a compressor fridge do they swallow up battery power 12v
bill

A lithium battery is not essential. A relative living in Scotland has a van with a compressor fridge and they use it in the winter for trips of three or four days without problems. 200W of solar and a 220Ah lead acid battery. Obviously a lithium battery would extend the time available off grid but they manage fine with their set up.

 

[Richard n Ann]

We ran our compressor coolbox in Benidorm. Easily enough power with the 150w panel and 100ah battery. The panel had the battery charged again by lunchtime while running the fridge half the time too Beni is rather sunny though

 

[DBK]

I'm thinking about getting a Dometic crx50 if I ever save up enough pennies. That has an "average consumption" of 40 watts. So at 12V that's about 3.3 amps.

As I understand it that isn't constant. It will turn on and off based on when it reaches the set temperature. So it changes.

But a compressor is supposed to be much more efficient than a 12V absorption type or a 240V household one.

In energy terms absorbtion fridges are not hugely efficient, making cold from heat isn't the easiest thing to do. But running an absorbtion fridge from gas is hugely convenient and your gas bottle will last longer than your battery.

Compressor fridges are more or less the same whether they run on 12 volt or like a domestic fridge on 240 volt. Running an absorbtion fridge on 12 volts only works when the engine is running except for those with huge amounts of solar.

 

[cmcardle75]

I'm thinking about getting a Dometic crx50 if I ever save up enough pennies. That has an "average consumption" of 40 watts. So at 12V that's about 3.3 amps.

As I understand it that isn't constant. It will turn on and off based on when it reaches the set temperature. So it changes.

But a compressor is supposed to be much more efficient than a 12V absorption type or a 240V household one.

With good installation (which means decent ventilation) a CRX50 can get down to an average of 1.5A even in warm weather. That's 40 minutes daily driving with a 60A B2B (plus a bit more for your other loads) or an hour and a half of decent mediterrean sun with a 400A solar array.

If you sit still in Scotland in November, you'll need EHU or enough battery to last.

 

[CamperJack]

A lithium battery is not essential. A relative living in Scotland has a van with a compressor fridge and they use it in the winter for trips of three or four days without problems. 200W of solar and a 220Ah lead acid battery. Obviously a lithium battery would extend the time available off grid but they manage fine with their set up.

I think a lot of my power will come from my B2B in the winter. If Wildbill is concerned about the fridge using too much power I would highly recommend installing a B2B if you don't have one and don't stay sat in one place for a long time.

When I was designing my power system I installed the B2B before solar because you can always drive but you can't make the sun shine.

Obviously a B2B requires driving. It works for me because I tend to move every day.

Do you have a B2B, Wildbill?

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[Wildbill]

They will clearly take a significant amount of 12V. However, if you design your 12V system correctly, this can be catered for. You do get significant advantages with a compressor fridge, such as not using any gas supplies, not requiring gas engineer servicing, greater reliability, an actual ability to cool things down, ability to use solar power, larger usable capacity for the same space taken, greater flexibility in location, no need to puncture the vehicle skin...

Just don't expect to off grid for a week with a 100Ah lead acid, no solar and a split charge relay. And if a pine needle dropping in the next field wakes you up, forget it.

You'll need at least one of: decent solar (and enough daylight to make it work), occasional electric hookup, a B2B (and enough driving to activate it), or a large lithium battery to last out your trip.

all of that sounds good so will 2x 800 AH battery's be ok with 600w of solar or it might be more
work payload not a problem
bill

 

[Wildbill]

I think a lot of my power will come from my B2B in the winter. If Wildbill is concerned about the fridge using too much power I would highly recommend installing a B2B if you don't have one and don't stay sat in one place for a long time.

When I was designing my power system I installed the B2B before solar because you can always drive but you can't make the sun shine.

Obviously a B2B requires driving. It works for me because I tend to move every day.

Do you have a B2B, Wildbill?

No BTB yet but i think i will be getting it
BILL

 

[cmcardle75]

Obviously a B2B requires driving. It works for me because I tend to move every day.

Do you have a B2B, Wildbill?

I decided in the end not even to install the solar. An hour would be an exceptionally small amount of driving for me every day. The solar would have been ugly and reduced fuel economy by more than I saved in free energy. I spent the money on 300Ah of lithium instead. I'm pretty sure I'll never run out. The only serious loads are diesel heating, compressor fridge and a 22" LCD TV. If the BMS starts complaining, I'll just shell out for a proper campsite for the night.

 

[cmcardle75]

all of that sounds good so will 2x 800 AH battery's be ok with 600w of solar or it might be more
work payload not a problem
bill

That would typically run a lot more than a compressor fridge!

 

[Wildbill]

That would typically run a lot more than a compressor fridge!

And i have just been informed by my son two more battery's might be available 3200 AH so that will be 4x800 think i wont have much problems led lights 12v TV DVD player radio computer microwave and paint on a new water line
bill

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[cmcardle75]

And i have just been informed by my son two more battery's might be available 3200 AH so that will be 4x800 think i wont have much problems led lights 12v TV DVD player radio computer microwave and paint on a new water line
bill

That's some serious weight, assuming lead acid. I mean a 12V 800Ah battery would weigh nearly 200kg. Are you sure they're not 800Ah 2V cells? (which would be a more reasonable 33kg) The bad news there would be that you'd need 6 of them in series.

 

[Wildbill]

That would typically run a lot more than a compressor fridge!

so that's good then

That's some serious weight, assuming lead acid. I mean a 12V 800Ah battery would weigh nearly 200kg. Are you sure they're not 800Ah 2V cells? (which would be a more reasonable 33kg) The bad news there would be that you'd need 6 of them in series.

There going on my boat there lead acid might nead to paint another water line i can get x 6 in the battery hold and probably another two we would be hoping to more off grid three to five days all year round and probably run a Generator From time to time

bill

 

[Raul]

A CRX 50, takes 320-380wh daily, or 25-30ah in amps. And no, it does not have variable speed like a inverter compressor. At least that’s what I noticed and nothing in the specs anyway. It can draw 40-45w depending how effective is the condenser ventilated. If you shove it in a tight cupboard, it will labour hard. Next to window for the sun to shine on it will not help. The noise is the same, depends how is installed. I have mine at my feet and only hear it when it starts, sometime. Also the cooling settings will determine consumption, we pulled the top shelf out and is a fridge on 3deg setting the hole think. We do have a separate compressor fridge, that has eco function with variable speed. That one is at the back, holds 45l and it takes half the power of the CRX 50 , amazing down to -20 deg, but we set at -14 is enough.

 

[cmcardle75]

so that's good then

There going on my boat there lead acid might nead to paint another water line i can get x 6 in the battery hold and probably another two we would be hoping to more off grid three to five days all year round and probably run a Generator From time to time

bill

You never said it was for a boat! You'll need to crane 'em in though!

 

[Wildbill]

You never said it was for a boat! You'll need to crane 'em in though!

There truck battery's there heave but can be lifted by hand i dont need a crane i have a Steve or honey monster as wee call him
bill

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[Richard n Ann]

About ventilation :
I'd always take the temperature of the dryer in the pipework, it's OK for it to be warm, especially when the fridge is pulling down. But if it's hot the head pressure is too high, the compressor will be using more power and will have a reduced life span. The condenser probably isn't condensing all the refrigerant back to a liquid either so it will run longer, also the evaporating temperature will be higher, all bad

An extractor fan thermistor could be fitted to the dryer to switch the fan on at 40°c

 

[Wildbill]

I must correct myself there 135 AH 750 cranking amp 540 AH
it's this type i can fill them with distilled water and carry out maintenance on them them
i dont like sailed battery's every single seal battery i have had fail was to a dry cell
bill

 

[Wildbill]

About ventilation :
I'd always take the temperature of the dryer in the pipework, it's OK for it to be warm, especially when the fridge is pulling down. But if it's hot the head pressure is too high, the compressor will be using more power and will have a reduced life span. The condenser probably isn't condensing all the refrigerant back to a liquid either so it will run longer, also the evaporating temperature will be higher, all bad

An extractor fan thermistor could be fitted to the dryer to switch the fan on at 40°c

I will probably run a computer fan drawing air from near the hull below water line probably constant temperature will that cure the problem.
bill

 

[Richard n Ann]

I will probably run a computer fan drawing air from near the hull below water line probably constant temperature will that cure the problem.
bill

Yes probably, stick a cheap digital thermometer sensor on the dryer the dryer is the little torpedo shaped cylinder with the capillary tube coming out.

 

[Raul]

There truck battery's there heave but can be lifted by hand i dont need a crane i have a Steve or honey monster as wee call him
bill

Do yourself a favour and get two 6v blocks of Trojan t125 or rolls surrette s300. Don’t bother with truck batteries, and fit hydro caps, instead original caps. It will save you allot of water top ups. I use rolls surrette 6v on the house, 8 of them for 48v system. Fitted new in March 2016 and still going strong. A hydrometer is mandatory, it will tell you exactly the health and state of the batteries like no other devise. I got hydrovolt that has the temperature compensation built in, made in Germany and very accurate, about 15 quid. Or a durite floater but you need to measure at 20 degC or calculate the temperature compensation.

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[walburga]

A few years ago I swapped out a poor performing 3 way fridge for an old 2nd hand 12v compressor fridge...worked great!
3 months over winter in Spain, no EHU, 150 watts solar, 2 x 110 amp LB's...it was very quiet as well. It possibly benefited from the original vents for the 3 way fridge.

Allen

 

[cmcardle75]

There truck battery's there heave but can be lifted by hand i dont need a crane i have a Steve or honey monster as wee call him
bill

You've got some of the numbers wrong then. A truck battery (i.e. 629) is around 180Ah and 45kg. There's no magic that would make a 12V 800Ah lead acid possible to lift by hand. Check they're not 2V, rather than 12V.

 

[chaser]

I just put this on Northernraider thread , so it was handy to post again, this is what we have in our van, 100w solar and two 100 a battery's will keep this going for three days in the sun, and will keep frozen stuff frozen in South of France temperature.
Excellent things.

 

[funflair]

You've got some of the numbers wrong then. A truck battery (i.e. 629) is around 180Ah and 45kg. There's no magic that would make a 12V 800Ah lead acid possible to lift by hand. Check they're not 2V, rather than 12V.

Bill corrected himself and they are 135ah each so yes they would be manageable by hand I wouldn't want to drop one in the hull of a boat though

I don't know what people do about venting lead acid batteries in boats but having Hydrogen Sulphide sitting in the bottom of the hull doesn't sound safe to me, don't want you to blow yourself up Wildbill

 

[Raul]

Hydrogen vents upwards, it’s such a light and small molecule gas that is very hard to contain. The smallest of vent, gap, will let it out. The concentration of hydrogen air to combust is quite high, hence minimal ventilation is more than enough. Besides, the gas escapes on excessive gassing only, if he gets the voltage right for his use and conditions, it will have very little gassing. Hence I recommended the hydrocaps. They are specifically designed to recombine the gases back into the solution and return to the cell. I got mine fitted from new, and minimises the water top up, despite high absorb voltage.