Hi all. If I want to charge my leisure battery from a solar panel when off grid, in the UK. What so I need? Has anyone done this? I have seen loads of kits but have no idea what size panel to use. It is to charge the leisure battery, in the day time, while out and about and away from the camper. It is a 90ah leisure battery.
That's an easy answer, it won't work on that fridge ... The subject has been done to death on here and it worked for me and dozens of others but you've got be realistic with the sums . Sent from my SM-G960F using Tapatalk
42W is 3.5A . As you will have maybe 12 hours not charging the battery every day on a good day, during those 12 hours it will use 50% of your battery charge . If the next day is dull , your battery will be being killed the next day.. Start with a better fridge - compressor fridge which can be more like 15W average and the numbers make more sense. You will save on using smaller solar panels and having fewer knackered batteries pretty quickly to recoup the extra cost of a better fridge. Depending on the poptop or other roof layout, you can easily fit between one and three off 100 watt panels. MPPT controller rated to more than 10 amps x number of panels is required.
all the time? Or only at cooling for some minutes of an hour? Did you measure it? My new compressor fridge is cooling for 1-3 minutes - and then in sleep mode for 15 minutes - and not draining all the time the battery. Calculate your consumption in Ah (Ampere hours for 12V). Keep in mind the time without sun in your calcuations/comparisons. And that a solar panel with 50 Wpeak not reach that optimistic 50W at normal condions with some sun, with clouds it drops down less then 20-50%, etc. I use a 70Wp at a 70+95Ah battery setup, but for sunny south Europe and Africa. For north Europe I would double the solar panels. regards,
Thank you guys. I now have a good starting point. The lower amperage fridge seems a good start. As we will be in The UK it seems that 100w panels will not be enough. More research to do I think, but you have given me some good food for thought. Thank you
The Dometic crx50 is a great fridge although 'branded' cheaper clones are available , think JK ... I bought one about 5 years ago and linked to a basic 100w panel its been a brilliant off grid solution. Sent from my SM-G960F using Tapatalk
my general setup including Mobicool MCG15 fridge is documented online at https://www.vw-t2-bulli.de/electrics-de.html regards,
I purchased a Dometic CRX50 fridge this year, to replace my 3 way gas/12v/240v absorption fridge - and last weekend at Techenders was the first time I'd actually had a chance to use it in a proper camping situation. I was very surprised with how little the compressor appeared to need to work to keep everything nicely chilled. I have 180W of solar panels on my roof, so it made sense to eventually upgrade the fridge situation to make use of the free power (the gas one still works perfectly if anyone wants to buy it ) and even running the propex heater for a while in the evening, plus phone charging and music / watching a DVD when it was raining, didn't dent my leisure battery charge too much - and the daylight topped it up quickly.
Is that in a fairly cold ambient? My compressor fridge runs almost constantly during a 35c summer day, but two 120w panels keep up with the load and charge the 176Ah leisure battery.
Like others I run a compressor fridge (Dometic, expensive but excellent). Linked to a 90Ah repurposed starter battery (so not a dedicated leisure one). Fridge set to 3degrees. I have not had any issues with this setup keeping up with demand. I find that typically as outside temps rise, then so does the solar input. With the reverse, if its cloudy and raining the fridge does much less work anyway. Only thing you need to watch is the shady campsite scenario, where the panel is not getting full access to the sun.
than yours is probably less isolated than mine or used differently. I have only small capacity with much isolation that works good for me. It is adjustable and check automatically the temperature and start cooling again falling less than 3 degress (histeresis) to the setup temp. I don‘t need ice (even if it possible), and use a range +4 to +10 depending what need to be cooled and how long to use less power. I try to avoid opening long or often. But more about it after my next upcoming Sahara trip… regards,
Yes, the fridge and use are very different. My Waeco CR-50 has nearly three times the capacity and I need ice (for G&T’s) but it is well insulated and vented top and bottom. I use it all year round, when it’s hot and also when it’s cold and the difference in running time is dramatic. A few weeks ago, on a trip from France through England up to Scotland and back home through Holland, Belgium and Luxemburg, the temperature was seldom about 10c and the fridge was off for long periods, conversely last summer during many days of 40C+ the fridge was on almost constantly, day and night. It is rated at 1.7 Ah/h at +32°C ambient but it’s probably more if the door is opened a few times I suspect your testing has been done while it is cool and it’ll probably be a bit different in the Sahara.
Doing it now, wild camping, but the fridge is one of those Calor glorified coolboxes, we froze all our ice blocks last night on a campsite and now we are using it just as a cool box rather than switching it on and draining the leisure battery.
