Hi, I am going away camping soon on different campsites. Some of these do not have electric but it will only be for one night or so at a time. I have a dometic fridge and I would like to keep it running at all times.

So far all I have is a 300W inverter. I am about to purchase a leisure battery from either a caravan stockist or Halfords etc. What size battery will I need to keep the fridge running all night and charge a couple of phones?

Also I am planning on getting a plug in battery charger to charge the leisure battery when I get to a campsite that has electric. Is this the best way to do things? I was looking at Solar but I haven't got a lot of spare space. Will something like this [url]https://www.amazon.co.uk/Maypole-7423A-Battery-Charger-Electronic/dp/B009A83P1E/ref=sr_1_5?keywords=leisure+battery+charger&qid=1566248460&quartzVehicle=29-405&replacementKeywords=leisure+battery&s=gateway&sr=8-5 do the job?

Hi

Is it an electric only fridge, or 3-way (12v, 240v & gas)?
It also depends if its an absorption type fridge, or one with a compressor.

If it has a compressor, I would be very wary - as there is a motor in there, you might cause damage, depending on the inverter type.
Cheap ones output a stepped square wave rather than a sine wave and this might give issues.
Probably the same with modern switched mode power bricks, used for the phones. (Wouldn’t a 12v charger be better anyway here?) Current: FL2 TD4 2008 HSE

Previous: FL1 TD4 2002 // FL2 TD4 2008 // FL1 TD4 2003 // TD5 Disco 2003 // 300TDi Disco 1994

Your advert for your charger seems to say that it is suitable and will not overcharge battery.

Try this link to help work out battery capacity.
https://www.caravansplus.com.au/guides/cal...-a-44.html FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

What is the load of the fridge & all other items. If the fridge is 3way it will use 12amps continuously. So battery is out of the equation. Use gas.

I have DC to DC charger in the car so my auxiliary battery (4 X 26ah) are charged between campsites. The fridge uses 15ah per 24 hours. So running the battery down to 50% I have 3 days.

Driving between campsites down under is hours so enough time to charge the battery up again.


If using a 240 volt charger. You may have limited amps in the evening to run other stuff, so you might only be able to charge when other items are off. If you have a 100ah battery & it is 50% flat you need more than a 4amp charger. Probably 10amps is the go & it will go into trickle mode. I have a 10amp Victron. It also has a low setting of 3amps. Procrastination, mankind's greatest labour saving device!

Acoustic insulation ARB TPMS 3xARB air compressors After cooler Air tank On-board OCD pressure air/water cleaning Additional 50L fuel Carpet in doors ABE 2x1kg Waeco 28L modified fridge Battery 4x26ah Solar 120w Victron MPPT 100/20 DC-DC 18amps 175amp jumper plug Awning 6x255/60R18

Quote:

Is it an electric only fridge, or 3-way (12v, 240v & gas)?
It also depends if its an absorption type fridge, or one with a compressor.

Quote:

If it has a compressor, I would be very wary - as there is a motor in there, you might cause damage, depending on the inverter type.

Quote:

(Wouldn’t a 12v charger be better anyway here?)

Quote:

Try this link to help work out battery capacity.
https://www.caravansplus.com.au/guides/cal...-a-44.html

Quote:

I have DC to DC charger in the car so my auxiliary battery (4 X 26ah) are charged between campsites. The fridge uses 15ah per 24 hours. So running the battery down to 50% I have 3 days.

Driving between campsites down under is hours so enough time to charge the battery up again.

Another useful link.

Some useful power usage figures for appliances on page 2. Also worth noting that some smaller sites only have 5amp outlets.

Many years ago, before motorcaravans were equipped with mains/12v power, I installed a 12v leisure battery and mains/vehicle charging in my van.
I wired in a standard main battery charger to charge battery whilst on site.

You can get specialist combined control boxes for camping/caravanning these days.

Two things worth noting,
Make sure that the extra battery/caravan supply is only connected to vehicle when it is running and charging (relay),
Use appliances which have a low average power consumption (duty cycle).

https://www.campingandcaravanningclub.co.u...ravanners/ FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Or am I over complicating things? Maybe something like this would do? https://www.amazon.com/NOCO-GB70-UltraSafe...B016UG6PWE

It could be charged up on site when we have a site with electric or via the 12V car socket when on the move

It should be able to run the fridge overnight?

Last edited by a100ian on 20th Aug 2019 4:54 pm. Edited 1 time in total

Found this thread, might be useful reading it all, but this post is what I was talking about: http://www.ybw.com/forums/showthread.php?4...ost5730218 Current: FL2 TD4 2008 HSE

Previous: FL1 TD4 2002 // FL2 TD4 2008 // FL1 TD4 2003 // TD5 Disco 2003 // 300TDi Disco 1994

After doing a bit more searching the Battery booster is not a good option so I am back to leisure battery and then some way of connecting it to my fridge and charging it. After Grubbys comments I am a bit worried about using my inverter as it is not Pure Sine, so any help is welcome.

The fridge will run off the car 12V socket whilst it is running it is just on a night on the occasional campsite without electric.

I like the idea mentioned of the split charge/relay but I don't think I will be able to get that done before this trip.

If the fridge works off 12v in the car, why don’t you just get a leisure battery as you planned and connect the fridge 12v direct to that?

Split charge is really easy, just use a caravan charging box, like this: https://www.towsure.com/self-switching-sma...-electrics

Connect the leisure battery and fridge to this box, and a 40a cable to the battery positive. (Thicker the better to prevent voltage drop)

When driving the fridge will work and leisure battery charge from car alternator.
When need 12v disconnect the fridge 12v from the box and connect directly to the leisure battery. Current: FL2 TD4 2008 HSE

Previous: FL1 TD4 2002 // FL2 TD4 2008 // FL1 TD4 2003 // TD5 Disco 2003 // 300TDi Disco 1994

Thank you Grubby, this is definitely the best solution and the one I am going to look into doing. Thanks again for the help.

What’s the amperage of the fridge and the size of the battery as you only have 1/2 the amperage before the battery’s flat and about 30 to 50% loss through an inverter

The Victron inverters are 87% efficient.

If the fridge is full & has a lot of thermal mass, containers of water to fill gaps. Run the fridge a bit colder when you have power, it will be ok overnight, one night at a time.

I would not rush into things before a holiday, that's when you make mistakes, end up with not what you needed & waste money.

A few links about my setup:
https://www.freel2.com/forum/topic33107.html

https://www.freel2.com/forum/topic34006.html

https://www.freel2.com/forum/topic32827.html

https://www.freel2.com/forum/topic31435-30.html

Now I have 4 X 26ah batteries. I don't absolutely need it but it is nice to have a bit extra. The fourth battery is on the floor so I lost a bit of space for water. We found we could get away with a bit less water. We just buy 10L packs if we feel we need a bit extra & juggle the space a bit more.

Under the driver's seat are compressors so that room is gone for batteries, but I have been thinking of rearranging everything! https://www.freel2.com/forum/topic30454.html Procrastination, mankind's greatest labour saving device!

Acoustic insulation ARB TPMS 3xARB air compressors After cooler Air tank On-board OCD pressure air/water cleaning Additional 50L fuel Carpet in doors ABE 2x1kg Waeco 28L modified fridge Battery 4x26ah Solar 120w Victron MPPT 100/20 DC-DC 18amps 175amp jumper plug Awning 6x255/60R18