Compressor fridge calculation

[Nesting Zombie]

Trev,
What’s you favourite Gulpa ?

 

[Robmac]

I wondered that two, its says on the back plate 250mA. i dont think thats correct as it only ran 24 hrs before the battery was well down.
Got me thinking now.

That's without the inverter coming into play Trev.

I'm not doubting your post - I don't know what your test conditions were and I've had results from batteries over the years which appear to not be possible as I have stated before, just seeking clarification.

Even so, 50ah isn't bad from a 240V fridge which is probably quite a bit larger than my 12v Compressor and I know a few people who use your setup (with larger batteries though).

 

[bartman]

I like the look of this one - I normally try to avoid buying from amazon, but this appears to be a rebadged Alpicool, a brand that I've seen praised on here. It's the CR85X but over £100 less than elsewhere.
On an unrelated matter, why are all my posts coming out in BOLD?

 

[trevskoda]

Trev,
What’s you favourite Gulpa ?

Milk.

 

[trevskoda]

That's without the inverter coming into play Trev.

I'm not doubting your post - I don't know what your test conditions were and I've had results from batteries over the years which appear to not be possible as I have stated before, just seeking clarification.

Even so, 50ah isn't bad from a 240V fridge which is probably quite a bit larger than my 12v Compressor and I know a few people who use your setup (with larger batteries though).

It was tested in my workshop at about 10/14 c, i put it on early and next evening it was still running, just about, smart charger when put on showed a amber charge light, it took a long time to full charge at 6 amps output.
No installed in van with 200w solar the voltage never drops in daytime below 13.4 ish, but at night i have no idea so may try a test on that, thing is i have 2 90amp batteries so maybe have to devide by 2 and also maybe take 20% of that to be sure, all i know it has never scalded the batteries in the van.

 

[Chasn]

Unless you are going to spend long periods off-grid with a lead acid battery a compressor fridge is definitely the way to go. I just bought an Alpicool for £216 which has individual fridge and freezer settings and has bluetooth which enables setting and monitoring on my phone. Current draw when running is 8A but the run time is much less than a 3 way (typically half). Given that my previous 3 way took 15A the overall energy consumption is now about 25% of what it used to be.

 

[exwindsurfer]

Unless you are going to spend long periods off-grid with a lead acid battery a compressor fridge is definitely the way to go. I just bought an Alpicool for £216 which has individual fridge and freezer settings and has bluetooth which enables setting and monitoring on my phone. Current draw when running is 8A but the run time is much less than a 3 way (typically half). Given that my previous 3 way took 15A the overall energy consumption is now about 25% of what it used to be.

One of our group. has just bought the same fridge and is well pleased with it he has I think 200amps of lithium and 820watts of solar.

 

[r4dent]

I wondered that two, its says on the back plate 250mA. i dont think thats correct as it only ran 24 hrs before the battery was well down.
Got me thinking now.
This all i can find online.

That "1 amp every 4 hours" was actually 1 amp hour at 230v. i.e. 20 ah every 4 hours at 12v.
see post #26 for detail.

power = amps x volts

 

[wildebus]

That "1 amp every 4 hours" was actually 1 amp hour at 230v. i.e. 20 ah every 4 hours at 12v.
see post #26 for detail.

power = amps x volts

bear in mind that is the power when running and the duty cycle of the fridge means it won't actually be drawing the equivalent of 20Ah@12V every 4 hours

 

[Harrers]

I had this same quandary in 2023. The original Electrolux absorption fridge in our van refused to stay alight on gas. I had already replaced every part possible on it. I thought about a 240v compressor running on an inverter but realised I would probably need to upgrade my 12v system completely. I only have one solar panel of unknown size and also the same controller that came with the van. My two existing 110ah batteries cope adequately at the moment even though we run 2 CPAP's every night. I looked at the replacement Dometic three-way fridges and decided they were too costly so in the end I purchased a Vitrifrigo 3-way. Still fairly costly but I wanted to keep the ability to run on gas.
Apart from a problem with being unable to use different settings when on EHU, I have been pleased with it so far. It turned out that a micro-switch behind one of the push buttons had broken. As it was still in warranty, the manufacturer sent me a replacement front panel which I fitted.
However, as with all absorption fridges it's performance is not great in very hot weather. So, I have recently fitted 2 small 12v fans in front of the metal fins to circulate the cold air. They are switchable so we can use either or both or none. Initially, these seem to help but we haven't had a chance to test them thoroughly yet. I used all plastic fixings to avoid any possibility of rust.
We may be heading down to Frejus next week but not sure at the moment and also of course it may not be that hot!

 

[Nesting Zombie]

Interesting ,
Let us know your findings in a few weeks,

 

[r4dent]

bear in mind that is the power when running and the duty cycle of the fridge means it won't actually be drawing the equivalent of 20Ah@12V every 4 hours

which is why I suggested using 50ah @ 12v per 24 hours.

the problem is that people are using "1 amp every 4 hours" (which is of course a meaningless statement) as being the same as""1 amp hour every 4 hours" then assuming it is a 12v figure whwn then post clearly says 230v and making all sorts of erroneous calculations. ( e.g post # 18 - a 90ah 12v battery will run a fridge for 15 days).

 

[barryd]

How do you find these compressor fridges that are exactly the same size as the three way fridges in motorhomes that fit exactly into the slot in the kitchen they were intended for? I had a brief look but they all seem different sizes. If it ever comes to the day when our right now very reliable and very good 3 way packs up I would need to find one exactly the same size and its a bigun. Then by the sound of it Jodrell bank (dish) would have to come off the roof and a huge solar array in addition to what we have and a lithium set up like Robs would be needed.

To be honest I thought Gas would be an issue on this trip but it really hasn't been. LPG still widely available in France. The only place we came close to running out was the Pyrenees but that was only because we were so high up for weeks on end.

 

[wildebus]

How do you find these compressor fridges that are exactly the same size as the three way fridges in motorhomes that fit exactly into the slot in the kitchen they were intended for? I had a brief look but they all seem different sizes.

Jackson Leisure have a downloadable file for both Thetford and Dometic that does exactly what you want.

If it ever comes to the day when our right now very reliable and very good 3 way packs up I would need to find one exactly the same size and its a bigun. Then by the sound of it Jodrell bank (dish) would have to come off the roof and a huge solar array in addition to what we have and a lithium set up like Robs would be needed.

To be honest I thought Gas would be an issue on this trip but it really hasn't been. LPG still widely available in France. The only place we came close to running out was the Pyrenees but that was only because we were so high up for weeks on end.

 

[barryd]

Jackson Leisure have a downloadable file for both Thetford and Dometic that does exactly what you want.

I'll have to give poor Merl a few years to get over my last upgrades really or until the lovely Gas Fridge packs up, whichever comes first

I'm not sure its a major thing for us. Everything has worked perfectly on this trip so far touch wood.

 

[Harrers]

Interesting ,
Let us know your findings in a few weeks,

So we returned from the campsite at St Raphael on Monday having arrived there early afternoon on Friday. We only use sites very rarely and this one is a 5 star and we stay there as my sister and bil usually stay there with Eurocamp each September. So we had EHU for the weekend. I had started the fridge on gas on the Wednesday and switched to 12volt for the journey down (about 5 hours with stop for lunch). I started the 2 internal fans as the journey started and also the 2 fans that assist the external airflow. Once on site we were on electricity so left all the fans running. The weather was quite warm - mid to upper 20's on Friday and Saturday. I am pleased to say that the fridge performed much better than when I had used it on EHU at my house earlier in the summer. I don't think we'll be getting any more heatwaves this year but I am much more optimistic about it's ability to keep things cold for next year.