Compressor fridge

[Mackyjane]

A friend is considering buying a 2 year old van conversion fitted with a compressor fridge. They have a 150w Solar panel and 1 leisure battery. Our only experience of a compressor fridge is when we had a 02 reg timberland which we bought in 03 and sold in 2010. We had 2 new leisure batteries and a 50w solar panel. We found that we struggled off grid after 24hrs as the batteries were low - we always assumed the fridge was the culprit. Has technology come on enough that the compressor fridges are now a viable option for off grid? The fact that so many new vans are fitted with them implies that they are better than they used to be. Has anyone had recent experience of these fridges?

[colin]

 Compressor fridges are viable off grid, but you need enough solar to run them and enough batteries to get through the night, your friends set up might be just enough to work, they will soon find out, if not they will have to add either battery or solar.

[mtravel]

It seems that Thetford will announce the "miracle" and Trigano group will adopt just compressor ones in 2024 production.

But this is the future, I feel good with my tri-fridge.

[peterjl]

Hi. It depends on the outside temperatures which influences how long the fridge runs, soooo  in outer Hebrides 3 days off grid was fine albeit we did drive short distances during the day which would help top up battereies.

On the other hand in Sweden a month ago with hot weather and brilliant blue skies would hammer battery overnight, still ok but wary about a second night without a good mileage to top up.

on our fridge there is an overnight setting which lowers consumption but I rarely bother and did not use in Sweden.

this is our first compressor fridge and I find I prefer over the gas/electric option.

peter

[mtravel]

Sweden ?

Try 48°C in Cordoba or 36 (midnight) in Delphi.

[hja]

We have a Dometic compressor fridge.  In a 2021 van. We like it as a fridge. It has a night time setting which we dont tend to use because as far as I could tell it just lowered the use until 5am in the morning and the fridge turns itself "off" as its not being opened overnight anyway. Remember, your domestic fridge is a compressor.

We had a 120w solar panel and a 95ah battery. Stayed at the Canterbury aire last year, arrived pm with fully charged battery, next day van stood all day while we went into Canterbury, weather poor, rain some time, little solar. Next morning battery was at 11.9v - obviously too low. It charged quickly once on the move but proved to us we could only do one night comfortably off grid without good solar. We have changed to a 230v lithium battery so now no problem. Have done 4 nights off grid very easily. Just went off site with van once, about 15 mins to somewhere and 15 mins back. Did have good solar. Only 4 nights because that's how long we were away. I think lowest battery dropped was to 78% which for lithium is obviously fine.

[Den]

Hi HJA 

just received notification after waiting for our new van that it’s arrived. 
with loads going on personally I overlooked the fridge is a compressor type. 
2nd battery being fitted along with a 100w solar panel, but from what you and others say I’m going to have battery problems. 
may I ask what make of lithium battery you fitted and price please. 
thanks 

Dennis 

[gassygassy]

I have just bought a one year old camper with a compressor fridge. And a diesel heater which consumes electric power of course. The camper appears to have had a second solar panel fitted because the two panels are different to each other. They total 240W. It has a quality MPPT regulator, which charges the batteries better than a regular cheap chinese one. The camper has two 110AH leisure batteries.

We have only been away once in it  and didn't use the heater so I can't comment on the working days of the fridge but it was absolutely fine over a long weekend without hookup. I think it will be OK. Perhaps the first owner of the camper found that one battery and one solar panel wasn't adequate and had the others fitted.

If your friend really likes the camper and is prepared if necessary to fit a second solar panel and second leisure battery then they should buy it. Assuming there is room on the roof for another panel, of course. If it doesn't need any more power then they'll save a few bob.

Also the current consumption depends of course on the fridge - a small one will consume less than a large one - the lower the fridge temperature, the more current it will consume - the sunnier the weather, the more power the panels will generate - the hotter the outside temperature, the more current the fridge will consume. The decision should rest on whether they are prepared, if necessary, to upgrade the solar panels and leisure batteries.

[Brian Kirby]

21 hours ago, Mackyjane said:

A friend is considering buying a 2 year old van conversion fitted with a compressor fridge. They have a 150w Solar panel and 1 leisure battery. Our only experience of a compressor fridge is when we had a 02 reg timberland which we bought in 03 and sold in 2010. We had 2 new leisure batteries and a 50w solar panel. We found that we struggled off grid after 24hrs as the batteries were low - we always assumed the fridge was the culprit. Has technology come on enough that the compressor fridges are now a viable option for off grid? The fact that so many new vans are fitted with them implies that they are better than they used to be. Has anyone had recent experience of these fridges?

As you will have gathered, there is no "one size fits all" answer to your questions. 

However, given more information, it might be possible to give a better reply than "it depends"!  🙂 

First, which make and model of van is involved?

Second, which make and model of fridge is installed and, if possible (from the users handbook for the fridge) what is its estimated power consumption.  This is likely to be further qualified by reference to ambient temperatures and/or climate zones.  As much info as possible will add to the picture.

Third, what capacity (in Ah), is the leisure battery, and if possible the battery make and model?

Fourth, if known, where is your friend intending to use the van, at what (broad) times of year, and to what extent do they intend to camp "off grid"?  The point of these questions is simply that there is a world of difference in how hard the fridge has to work (and therefore how much electricity it is using) between Southern Spain in mid-summer (with its high temperatures but relatively short nights (during which no solar power gain) and, say, northern Scotland in late Autumn, with its much lower temperatures - but much longer nights (with no solar power gain) and increased occupation electricity consumption from (lighting etc.).  The above are only relevant while off grid - if on EHU they should have no problems at all - providing the mains power doesn't fail of course!  🙂 

Finally, the van will have three ways to re-charge the leisure battery: from the vehicle alternator while driving, from mans power (via a battery charger) while on EHU, and from the solar panel - when there is sufficient light to generate an output.  This last point can be problematic even in southern climes: does one park in the shade to keep the van cool, and sacrifice some, perhaps all, of the solar power gain, or park in full sun and roast the van while the fridge has a nervous breakdown!

Increasing leisure battery capacity may fix off grid fridge power shortages, but may also require an uprated charger to match the higher charging demand, and/or the installation of more solar capacity (for the same reason), and/or more driving time between stops - because the van's alternator output is relatively limited, so to replace a given number of Amps consumed from a fixed input, the remedy has to be more time spent charging, and hence driving.

[Deneb]

I have an Isotherm compressor fridge, with 2 x 90Ah leisure batteries and 200W of solar. We use the van off-grid a lot, sometimes for weeks at a time, and have never had an issue. The caveat being that you have to understand and monitor your energy consumption. I would not be without our Victron battery monitor, which when reasonably calibrated, tells me the state of our batteries, time to go until the discharge floor is reached (set at 50%), current and averaged consumption, etc. at any point in time. By being aware of that information you can make informed decisions, such as when you might need to seek a battery recharge and when it might be advisable to moderate energy consumption by minimising the use of other devices, when we you excess power available that you can use to run or charge other devices etc.

Together with the additional solar panel (the van originally had a single 100Ah panel) I changed the Votronic PWM solar charger for their equivalent MPP version, fitted the Victron battery monitor, and also a B2B charger in place of the less efficient split charge relay that was also the default option on the van. I find the B2B charger, a 30 amp Votronic device, nearly four times as efficient as the split charge relay for recharging the leisure batteries.

In my experience, although the fridge is rated at 6 amps maximum consumption, it averages around 2Ah or slightly less, as the compressor only runs for about 10 minutes in each half-hour period. Weather conditions are swings and roundabouts. If it's hot and sunny, the fridge may use more power, but as long as you park where you can maximise sunlight on the solar panels, 200W will easily cover the fridge consumption and provide spare capacity in daylight hours. Of course in poor sun and/or typical British autumn and winters, there may be insufficient sunlight available, but if you are touring and driving for a couple of hours or so every other day, the B2B will keep the batteries topped up, otherwise with the information provided by the battery monitor, it is easy to see that you will need to factor in a drive in one or two days time if the solar provision doesn't improve.

We sometimes also avoid watching TV, read our Kindles in darkness, carry powerbanks that we can recharge when we have spare capacity and use to recharge phones etc. when we don't, turn off the fridge at night and move freezer packs from the freezer compartment to be distributed around the fridge, returning them to the freezer compartment the following day for further nightly use if necessary.

I have never discharged our batteries more than 47% and usually much less. We have toured Scotland for over 6 weeks in the autumn with only a couple of nights on EHU (and then more because it was there than out of necessity). I took a generator with us on that holiday, but never used it. All it did was stink the van out with petrol fumes. I've never packed it since.

The key to this is having the equipment to be able to charge the batteries, both by solar which is only as reliable as the weather, and other means also (the B2B charger) AND a good calibrated battery monitor that will give a fairly accurate assessment of your power situation at any given time.

But I would say that it is eminently do-able, and the compressor fridge beats the gas fridges we have previously had hands down. However, if like someone I know, you need to constantly use and recharge multiple gadgets, keep electric bikes recharged, always have access to a coffee making machine, can't not watch TV all evening, need the fridge to constantly be ice cold for your beer and to keep ice-creams frozen, and generally want you motorhome life to replicate your home life without being prepared to make adjustments to fit in with the restrictions of being off-grid, you will almost certainly struggle to survive!

[hja]

11 hours ago, Den said:

Hi HJA 

just received notification after waiting for our new van that it’s arrived. 
with loads going on personally I overlooked the fridge is a compressor type. 
2nd battery being fitted along with a 100w solar panel, but from what you and others say I’m going to have battery problems. 
may I ask what make of lithium battery you fitted and price please. 
thanks 

Dennis 

Eco Tree from Oak Tree Motorhomes in Nottingham. They fitted it, with a new mppt solar controller, and adjusted whatever needed adjusting for lithium.  Our charger and b2b were fine.

[Den]

Thank you HJA 

I’ll  probably try it for a couple of trips 3 or 4 days and see how it goes. I’m not hopeful though. 
thanks again 

den