leisure batteries and compressor fridge question

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griff71

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I'm in the middle of a major reno of a 1996 kontiki.
i'm almost at the point of redesigning the kitchen area and i'm seriously considering getting a compressor fridge to replace the old 3 way fridge that was in the van when i bought it.
we have 2x 115ah leisure batteries which i know won't quite cut it for the fridge if we go without EHU. my plan in about a year or so is to install solar and get some lithium batteries but at the moment i'm spent out on the renovations i've been doing.
my short term plan was to just get 2 pretty cheap leisure batteries to bump up my battery bank to 460ah and then get a b2b charger.
i know its not good practice to mix old batteries with newer ones but i'm only looking at it as a short term fix rather than expecting to get a 100% efficiency off my batteries.
any info or tips would be much appreciated as i don't want to commit to the fridge unless i know i can run it without solar for the time being
 
I would bite the bullet and have an 3way absorption fridge and save the worry.

They are not so much more expensive

www.justkampers.com

Thetford N4112-E+ Absorption Fridge Curved Framed Door (113 Litre)

This N4112E+ model has a curved framed matt black door with left hand hinging, which can easily be converted to the right side if desired. The secure closing door ensures the fridge remains closed when the vehicle is moving.
www.justkampers.com www.justkampers.com


Broken Link Removed
 
thanks for the reply.
my main issue with the fridge isn't the cost issue as such, its mainly that in the future i will be going for a solar set-up so it seems a better idea to get a compressor fridge for futureproofing.
i get what you're saying but i just want to get less reliant on gas (just for cooking) and get a fridge that will be eventually powered by solar and b2b charging.
 
I would go for solar now, add lithium later if you want to. 200W of solar will be enough to keep the fridge running and twinned with say a Victron 75/30 controller you will be set up with capacity for more panels to be added later. This makes sense if the alternative is buying two extra batteries which you are going to chuck away in a year. You could even go for a budget controller if necessary as long as you have the panels on the roof, adding a better controller later.
 
This may help in your usage calculations, our recently installed compressor fridge freezer when running draws 4.5 amps, but when cooled down uses about 40ah a day, it also has a night time setting which helps. It maintained -15°C in the freezer and about 6°C in the fridge during the heatwave. We have a pair of new Hankook 130ah batteries and 175w solar panel, the batteries remained at 80% soc or higher throughout the summer. Solar is definitely the way to go.(y)
Cheers
Ed

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cheers guys, i'll look into all options, the problem i have now is that i've done my budget fixing up the van so thought 2 batteries would be cheaper than getting solar, i'll have a shop around and compare prices as what you say does seem a more sensible option compared to my idea.
 
If I was you, first thing I would buy is a B2B and keep what batteries you have. It will run a compressor fridge. Then, add solar as DBK says, for when you are stationary, and controller can be upgraded later.
Expect 25-40ah per day for the fridge, more like 30ah ish, this depends on fridge placement, loading setting etc.
 
yeah my first purchase after the fridge was going to be a b2b,
we'll be moving around quite a bit when we finally get to use the motorhome so we should get a good amount of battery charge off that alone. i was just thinking of adding a couple more cheap batteries to increase my storage capacity as realistically i won't really be able to get solar sorted till next spring/summer.
i've had the motorhome for a year and its been stripped down to bare bones and slowly repaired-rebuilt and modernised. i just want to get it to a point that its useable before giving myself another task, ie, fitting and wiring up solar.
 
My 80ah gel battery has been great so far powering the compressor fridge. It uses about 12ah over night then the 150w solar charges the battery and runs the compressor simultaneously. Might struggle on dull days so I've bought a 100w folding panel to deploy if necessary. The compressor runs at about 2.7 amps.
 
Just a thought (dangerous I know).
U are going to spend on new batteries and a b2b so why not get a lithium battery and use that just for the fridge (not connected to main 12v system). If you could run to a cheap stand alone charger for when on hookup so much the better.
Wire it in such a way that u can easily integrate wiring into Van's 12v when u fit the solar. U can ditch the current batteries.

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berni109 said:
Just a thought (dangerous I know).
U are going to spend on new batteries and a b2b so why not get a lithium battery and use that just for the fridge (not connected to main 12v system). If you could run to a cheap stand alone charger for when on hookup so much the better.
Wire it in such a way that u can easily integrate wiring into Van's 12v when u fit the solar. U can ditch the current batteries.
Click to expand...
thats not a bad idea. i will look into that. thanks
 
If you do decide to change your fridge I would be interested in your old one if it's the same as mine 👍
Screenshot_20220914-222557.png
 
The power useage of a compressor fridge does depend on the efficiency rating of the fridge of course, but what be certain is that it will be massively more efficient than a 3-way fridge running on electric (the Compressor Fridge I fitted in my Motorhome is SEVEN times more efficient than the 3-way I took out).

I just looked at the logged data of my fridge power use (get a value recorded every minute) and for my 140L Fridge/Freezer fitted with a 230V AC Compressor, I get the following data on a sample 24 hours a few days ago:
When the Fridge is running, it draws 56W, and the DC current draw into the inverter (so this includes all the inverter overhead) is 5.03A.
The Fridge compressor is not running all the time, of course, and once the duty cycle is taken into account, the Fridge uses 16.8W and the DC current draw is 1.62A
This graph shows when the fridge is on and when it is off .... (I also am showing the Freezer temp so you can see how that is being maintained)
1663194944362.png

Over a full 24 Hours, that power use adds up to 403Wh per day that the Fridge uses, and 38.88Ah @ 12.6V inc DC-AC Conversion and Inverter Overhead.
My previous 240V Fridge I had in my old camper was more efficient at around 1.2A average (inc Inverter O/H) but was just a fridge, no freezer.

I decided to change the fridge over when the 3-way started playing up a bit. I sold it, a 14 year old Absorption Fridge, for only slightly less than a brand new Class A+ Compressor Fridge cost.
 
Last edited:
What you lose with a compressor fridge is the ability to run on gas, how do you manage in the winter when there is insufficient sunlight to recharge your battery?
 
Itsmcb said:
What you lose with a compressor fridge is the ability to run on gas, how do you manage in the winter when there is insufficient sunlight to recharge your battery?
Click to expand...
Mines SORNed in winter, if it wasn't I'd probably need another 150w tilting panel 🤔

Edit: A coolbox locked on the scooter rack would probably be cool enough in the UK though, that's the great thing about using solar for refrigeration, in winter when there's less light, you don't need it 😊

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Only just seen this thread so all this might have been said , but when I did ours , I put a compressor fridge in, don't know the figures but it is bigger than the old three way ones, it's been the best thing we have in it, I started off with two 100 a batteries and one 100w solar, with no problems at all, that's it nothing else and you will get a solar setup for less than two more batteries.
Although I will say during the winter I added another solar, just because I could basically, and now we are overrun with electric, the batteries never show anything less than 12.7. during the day we are up to 14 by ten o clock.
No b2b or anything else although this old ambulance has got some electrical gubbins under the front seat that clicks now and again and a light comes on so I am assuming it maybe something similar.
It works so I have left it alone.
But a long winded post to say I would get a compressor fridge and a solar panel.
 
Hoovie said:
The power useage of a compressor fridge does depend on the efficiency rating of the fridge of course, but what be certain is that it will be massively more efficient than a 3-way fridge running on electric (the Compressor Fridge I fitted in my Motorhome is SEVEN times more efficient than the 3-way I took out).

I just looked at the logged data of my fridge power use (get a value recorded every minute) and for my 140L Fridge/Freezer fitted with a 230V AC Compressor, I get the following data on a sample 24 hours a few days ago:
When the Fridge is running, it draws 56W, and the DC current draw into the inverter (so this includes all the inverter overhead) is 5.03A.
The Fridge compressor is not running all the time, of course, and once the duty cycle is taken into account, the Fridge uses 16.8W and the DC current draw is 1.62A
This graph shows when the fridge is on and when it is off .... (I also am showing the Freezer temp so you can see how that is being maintained)
View attachment 664487
Over a full 24 Hours, that power use adds up to 403Wh per day that the Fridge uses, and 38.88Ah @ 12.6V inc DC-AC Conversion and Inverter Overhead.
My previous 240V Fridge I had in my old camper was more efficient at around 1.2A average (inc Inverter O/H) but was just a fridge, no freezer.

I decided to change the fridge over when the 3-way started playing up a bit. I sold it, a 14 year old Absorption Fridge, for only slightly less than a brand new Class A+ Compressor Fridge cost.
Click to expand...
thats pretty good considering the size of your fridge freezer. i'm deffo going to get a compressor fridge. i've been looking into solar and also b2b chargers and will be investing in both to help us be totally non reliant on EHU or at least minimally as UK weather cannot guarantee solar all year round.
 
Itsmcb said:
What you lose with a compressor fridge is the ability to run on gas, how do you manage in the winter when there is insufficient sunlight to recharge your battery?
Click to expand...
i've weighed it up and if i was to have 200-300ah worth of lithium eventually (£££££) and a b2b charger combined with solar then i think it will be do-able, if shit hit the fan then i would spend a night now and then where there is EHU but i think with lithium-solar-b2b combo the EHU hookups will be few and far between.
our motorhome will be mainly used by me, my partner and our dog, we're not really power hungry so if i can run a fridge, lights, etc, and maybe a decent sound system and occasional telly the all should be good.
also i will check out the fridge for you in a bit👍
 
chaser said:
Only just seen this thread so all this might have been said , but when I did ours , I put a compressor fridge in, don't know the figures but it is bigger than the old three way ones, it's been the best thing we have in it, I started off with two 100 a batteries and one 100w solar, with no problems at all, that's it nothing else and you will get a solar setup for less than two more batteries.
Although I will say during the winter I added another solar, just because I could basically, and now we are overrun with electric, the batteries never show anything less than 12.7. during the day we are up to 14 by ten o clock.
No b2b or anything else although this old ambulance has got some electrical gubbins under the front seat that clicks now and again and a light comes on so I am assuming it maybe something similar.
It works so I have left it alone.
But a long winded post to say I would get a compressor fridge and a solar panel.
Click to expand...
thanks for that info. i will deffo be getting the solar and compressor fridge, i'm still going to get the b2b as its nice to have a back up but really glad to hear that solar sorts your needs as it makes me happier to part with my money knowing that its a good investment.
cheers
 
We’ve got a 90L Compressor fridge, with a small freezer compartment.

130w solar panel, 2 x 110 leisure batteries no b2b (no idea what that would do for me anyway, as I have no idea what one does :unsure: ). Solar charging split 70 /30 in favour of the leisure batteries.

Easily three days without EHU, but don’t normally stay anywhere much longer. We charge all our phones, iPads, torches, Bluetooth speaker whilst on the go…..but on sunny days the batteries always get topped up.

More than ample for our style of moving about.(y)

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Sapper520 said:
We’ve got a 90L Compressor fridge, with a small freezer compartment.

130w solar panel, 2 x 110 leisure batteries no b2b (no idea what that would do for me anyway, as I have no idea what one does :unsure: ). Solar charging split 70 /30 in favour of the leisure batteries.

Easily three days without EHU, but don’t normally stay anywhere much longer. We charge all our phones, iPads, torches, Bluetooth speaker whilst on the go…..but on sunny days the batteries always get topped up.

More than ample for our style of moving about.(y)
Click to expand...
Absolutely, ditto.
 
griff71 said:
thats pretty good considering the size of your fridge freezer. i'm deffo going to get a compressor fridge. i've been looking into solar and also b2b chargers and will be investing in both to help us be totally non reliant on EHU or at least minimally as UK weather cannot guarantee solar all year round.
Click to expand...
Basically, I looked for a compressor Fridge-Freezer that would fit into the same hole that removing the Thetford N180 would leave.
I nearly got a replacement Thetford T2165 (think that was the model?) which would be an exact-size replacement but 12V Compressor one. But I had a good experience of using a 240V Domestic Fridge in my camper and decided to go for that option again given it would be around 1/3rd the price.

New Fridge/Freezer was an LEC model which was around 2" narrower and shorter than the N180.
 
griff71 said:
this is the fridge i have,
Click to expand...
Ah, that's different to mine, that's strange. I am pretty sure mine is the original fridge for my van, it certainly looks old enough. Yours is quite a bit wider.
 
griff71 said:
cheers guys, i'll look into all options, the problem i have now is that i've done my budget fixing up the van so thought 2 batteries would be cheaper than getting solar, i'll have a shop around and compare prices as what you say does seem a more sensible option compared to my idea.
Click to expand...
Hi griff71 i have recently change to Lithium batteries, so I have 2x 85ah AGM batteries in my garage. If you are interested I could let you have them for a nominal fee.
DA917D73-FBC2-48C6-9037-0272A1488335.jpeg

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Itsmcb said:
Ah, that's different to mine, that's strange. I am pretty sure mine is the original fridge for my van, it certainly looks old enough. Yours is quite a bit wider.
Click to expand...
i'm not sure if my fridge was the original tbh.
 
Old Rascal said:
Hi griff71 i have recently change to Lithium batteries, so I have 2x 85ah AGM batteries in my garage. If you are interested I could let you have them for a nominal fee.
View attachment 664782
Click to expand...
i'm still weighing up my options at the moment, thanks for the offer and i'll deffo keep it in mind.
cheers
 

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