As the title say’s really, would I be ok running the small compressor fridge off a leisure battery for a few hours?

Cheers

Cant you work it out? Volts x Amps =w/hours or something.

Is it a 12v fridge, or are you using an inverter, or….?

You can back calculate from the wattage of the fridge.

Eg – 500w sticker draw on fridge:
Include losses in your calculation
500w out is probably <600w draw from inverter (hopefully less)

600w at 12V is 50A

So you’re using 50Ah (per hour)

Keeping leisure battery over 20% (battery care) means you have 80% of the battery’s Wh run time available:

eg 500Ah battery will give you (500*.8)/50 hours total run time.

Or 400/50=8 hours run time dropping 80% of the battery charge.

NB, peak/startup draw from a fridge is very high, much higher than the continuous power rating. Check your inverter is capable of that usage/peak draw or it maybe will disconnect the load.

If it’s a 12V fridge then just skip the efficiency calculation but use the same principles.

Few days on a compressor fridge, easy. Few hours on an absorption one. When we first went to Morocco we had a compressor fridge running on a single battery set up. Land rover started first time after 36 hours on the boat to Spain. We ate Choc Ices in the Sahara at 44 degrees C that had come all the way from the UK

should be (*based on modern motorhome/decent leisure batter/fridge experiences – ie been off grid for a couple of days using led lights, tv, fridge, all ok) but does depend on fridge power draw, batter capacity, condition charge etc etc

You probably know this but fridges tend to not work if the van isn’t levelish.

Great thanks. Wasn’t sure of all the factors to consider – the 20% battery care buffer is news to me and good know and take heed of and also the fridge not working if not level thing, though I can’t imagine that being an issue. I’ve started the fridge on the mains so just a case of keeping it ticking over for a few hours while we stop off en-route to the site, not going off grid just yet – only just got the van so taking things a step at a time.

If the fridge is supplied with the van then the inverter (if there is one) should be OK. When I say “at startup” I mean the fridge isn’t always running it’s cooling system, so it will start/stop all the time as needed to hold the temperature down.

NB all this refers to a condensor fridge, like you probably have at home, with a heat-exchange circuit and a warm metal tube/grid at the back.

Other types of small fridge exist that use solid-state cooling (a special type of transistor-related technology where a set of silicon squares pump heat from one side of the system to another. These types don’t draw extra current at startup, but tend to be pretty small. They are also called “peltier” heat pumps).

I think i’ve just got a 12v specific fridge, to my knowledge an inverter has not been installed on the conversion. Its a Webasto so looking at their website, though I can’t identify my exact model, it seems it is a conventional type compressor fridge. The fridge has been chilling overnight so will be easily down at temp by the time we set off this morning, especially when loaded up with cold produce.

I’ll take my jump leads just in case though!

Sweet – have a nice trip. If you’re going somewhere hot – take a solar panel!

On a 110Ahr, you are probably looking at 24hrs max for a compressor fridge.

Also, the ‘battery care’ is more like 50% max discharge before you start significantly shortening the battery life.

The compressor fridges are fairly tolerant and will work on an angle, its the 2 and 3 way gas/12v absorption fridges that are fussy about being level.

I’ve stuck 200w of solar on the roof, batteries start to deplete overnight but by the following afternoon they are 100% again with no other charging, thats with a Weaco CRX80 compressor fridge.

There you go. Loads of useful info, and yes 50% discharge for Lead acid looks much better for it than 80%!

Thanks again. I really can’t envisage it running off the battery for more than about 3 hours. Going nowhere hot taking a look out of the window just now, just a shake-down overnight stay at a campsite to test out the van – a complete noob to campervanning so i really don’t know what I don’t know. But got lots planned for this summer if we get one. 2 weeks in France, a few visits to Scotland to hook up with my brother, including some off-grid wild camping, so sounds like a solar panel will be needed and lots of other small weekend trips planned. Looking forward to the adventures!