Thetford Fridge

[Walkingmox]

We have changed from our lovely Burstner motorhome with a 3 way fridge to a camper van with a Thetford electric only fridge. Although we have a rooftop solar panel which runs the leisure battery and thus the fridge in grey weather or parked in the shade to keep cool will it produce enough to avoid using a campsite in order to plug into the electric. Sited just inside the sliding door ie: in the sun we need to run it on high to keep the freezer cold which seems to produce ice build up at the internal back wall and when this defrosts there doesn't seem to be an adequate well under the salad drawer to catch the ice so it floods the floor and carpet outside. we have never had any problem before. are we doing something wrong. can we wild camp and still run the fridge. Sorry lots of questions

 

[REC]

Depends on the size of solar panels/leisure battery and fridge size? We found we need to have an extra leisure battery as the fridge ran battery down fairly fast. We have a small electric only fridge but now often don't even turn it on, use it as a cold box in winter travels. Freeze 2litre bottle of water and keep it in the fridge rather than cold packs helps keep it very cool even in quite warm weather. Never had issue with water but our fridge is pretty small.

 

[molly 2]

Problem with solar is you get good days and bad days , this time of year only bad days ,

 

[Debroos]

We don't turn ours on much either. We recently discovered that if you freeze bottles of milk they stay frozen way longer than bottles of water!
Don't know why. Maybe the fat content? Still usable when melted.

 

[Sid]

We have changed from our lovely Burstner motorhome with a 3 way fridge to a camper van with a Thetford electric only fridge. Although we have a rooftop solar panel which runs the leisure battery and thus the fridge in grey weather or parked in the shade to keep cool will it produce enough to avoid using a campsite in order to plug into the electric. Sited just inside the sliding door ie: in the sun we need to run it on high to keep the freezer cold which seems to produce ice build up at the internal back wall and when this defrosts there doesn't seem to be an adequate well under the salad drawer to catch the ice so it floods the floor and carpet outside. we have never had any problem before. are we doing something wrong. can we wild camp and still run the fridge. Sorry lots of questions

Can't argue with what REC said. I am changing out our 3-way Thetford for the same size compressor fridge. The 3-way is just too inefficient uses too much gas and 12V when motoring. I have built a 330Ah LFP battery which with the other usage we have should give us around 4-5 days of fridge usage (~2-2.5kW)which is more than enough as I don't think I have ever stayed that long in one place. I am upgrading the solar a bit (adding an extra 200W) (won't help in Winter) which will compensate in warmer times and we have a modest 30A B2B charger.

 

[exwindsurfer]

I've ran a compressor fridge now for over 12 years I don't switch it off even when it's standing in the drive as it does my 400amps of lithium batteries some good as they never stand at 100 percent .I wouldn't entertain a 3 way fridge if they gave me it lol

 

[alcam]

I've ran a compressor fridge now for over 12 years I don't switch it off even when it's standing in the drive as it does my 400amps of lithium batteries some good as they never stand at 100 percent .I wouldn't entertain a 3 way fridge if they gave me it lol

Possibly getting a van with compressor fridge . 100w solar , 100ah leisure battery. All of that , long term , may change.
Always had 3 way fridge . Never had any problems. Flexibility sells it to me .
Given all of the above any advice on probable , new fridge ?
p.s. 400ah lithium not happening soon

 

[trevskoda]

Possibly getting a van with compressor fridge . 100w solar , 100ah leisure battery. All of that , long term , may change.
Always had 3 way fridge . Never had any problems. Flexibility sells it to me .
Given all of the above any advice on probable , new fridge ?
p.s. 400ah lithium not happening soon

I have 200ah lead acids and 200w solar, no bother keeping the fridge running 2/3 days without sun, otherwise no problem, but it is a small fridge as we can buy food fresh in shops and i dont stay away more than 1 overnight at a time.

 

[exwindsurfer]

I've had over a week on just batteries and no sun I think the batteries got down to 45 % so still had plenty left.

 

[alcam]

I've had over a week on just batteries and no sun I think the batteries got down to 45 % so still had plenty left.

So the set up I described is useless

 

[r4dent]

Possibly getting a van with compressor fridge . 100w solar , 100ah leisure battery. All of that , long term , may change.
Always had 3 way fridge . Never had any problems. Flexibility sells it to me .
Given all of the above any advice on probable , new fridge ?
p.s. 400ah lithium not happening soon

Couple of assumptions
a) the battery is a standard lead battery. The nominal 100ah will provide 50ah of usable capacity.
b) the compressor fridge will use 20 ah per 24 hours (cold at start)

How long the fridge run.
a) If there is no sunshine you be OK for 24-48 hours.
b) You be OK for longer periods for the month /locations were the 150w solar output (table below) is above 75.

Conclusion.
You will be OK touring with single overnight touring in winter or two night stays at other times.
Fot longer stays without EHU you need to upgrade both battery and solar.

 

[alcam]

Couple of assumptions
a) the battery is a standard lead battery. The nominal 100ah will provide 50ah of usable capacity.
b) the compressor fridge will use 20 ah per 24 hours (cold at start)

How long the fridge run.
a) If there is no sunshine you be OK for 24-48 hours.
b) You be OK for longer periods for the month /locations were the 150w solar output (table below) is above 75.

Conclusion.
You will be OK touring with single overnight touring in winter or two night stays at other times.
Fot longer stays without EHU you need to upgrade both battery and solar.

Thanks for that . Will investigate costs etc .
Easy short term solution I suppose would be to add another lead acid .

 

[wildebus]

Couple of assumptions
a) the battery is a standard lead battery. The nominal 100ah will provide 50ah of usable capacity.
b) the compressor fridge will use 20 ah per 24 hours (cold at start)

How long the fridge run.
a) If there is no sunshine you be OK for 24-48 hours.
b) You be OK for longer periods for the month /locations were the 150w solar output (table below) is above 75.

Conclusion.
You will be OK touring with single overnight touring in winter or two night stays at other times.
Fot longer stays without EHU you need to upgrade both battery and solar.

Major assumption on the fridge power there (I reckon will be notably higher).

 

[alcam]

Major assumption on the fridge power there (I reckon will be notably higher).

Actually don't know . It is smallish .
I know , a bit too scientific!

 

[trevskoda]

I've had over a week on just batteries and no sun I think the batteries got down to 45 % so still had plenty left.

Thats a tad to low for lead acids.

 

[Nabsim]

Compressor fridge/freezer will use approx 48amps in 24 hours, just a fridge will use approx 24amps in 24 hours. Like Geoff I run mine 24/7, I need approx 60/65amps every day for everything I use all in. For about 7 months of the year I can go indefinitely without moving (so long as we get some sun) but for 5 months of the year I need alternative power source. That's with 300amps of solar flat on the roof and 200Ah Lifepo4 battery bank.

 

[wildebus]

Possibly getting a van with compressor fridge . 100w solar , 100ah leisure battery. All of that , long term , may change.
Always had 3 way fridge . Never had any problems. Flexibility sells it to me .
Given all of the above any advice on probable , new fridge ?
p.s. 400ah lithium not happening soon

It really does depend what fridge it is.
The Thetford fridge/freezer the OP has has a nominal power consumption of 0.280Wh/24hrs - or just under 24Ah at a nominal 12V. In reality, it will be higher in use as the fridge gets used.
My Fridge/Freezer and Neils are pretty similar in consumption at around 50Ah/24 hours and are similar sizes, but are different makes.
Something like a Weaco/Dometic CRX50 - a very popular small Fridge that is fitted in campervans - has a quoted average of 1.1Ah/Day. However I ran a test and found my CRX50 would last 2.5 Days on 200Ah of Batteries without any solar before the batteries dropped to 50% so the real average was higher (no surprise there).

There are some fridges that are very efficient but they are not the typical ones installed. I need to check the make and model but one of my neighbours has a drawer-style fridge that he says is extremely efficient and seems to just sip the power. He does have a comparison as well as his old camper has a fridge that lasted on the batteries significantly less despite having twice the battery power.

Overall, for a Summer Camper, 200W of solar will replenish the power used by a fridge and general power use. 200Ah of battery (or 100Ah Lithium) will be enough to cover use overnight and cloudy spells until the sun has a chance to get some power back in.
Camping in Winter, not enough room on the roof for solar to do anything significant.