Power demand

Submitted: Thursday, Apr 11, 2013 at 00:07
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Can anyone help me with this. I need more cold storage when going away in our jayco campervan. I have a 160lt esky and a 3 way fridge. My ? is could i run a 2nd 3way fridge on same gas supply or go solar panels through inverter through batteries to run a fridge on 240v or 12volt through van, i'm not good on all this conversions. I know running fridge and small appliances through solar system uses 220AH'S per day thats based on using 4 x 115ah batteries. I have 2 115ah Trojan deep cycle batteries... hope someone can help.

Regards David.
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Reply By: The Bantam - Thursday, Apr 11, 2013 at 00:26

Thursday, Apr 11, 2013 at 00:26
Firstly understand that 3 way fridges are very inefficient running on electricity...very inefficient indeed.

If you want to be running on batteries/ solar you realy need to be talking compressor based fridges.

you also need to be running a 3 way fridge of an inverter run of batteries like a hole in the head.

The only saving grace thet 3 way fridges have is that they will run for quite a long time on a bottle of gas.

Have you seriulsy thaught about your need for cold storage......people PARTICULARY women have a tedancy to put all sorts of unnecessary stuff in the fridge and refrigerate lots of stuff that does not need it.

AnswerID: 508707

Follow Up By: Ross M - Thursday, Apr 11, 2013 at 11:32

Thursday, Apr 11, 2013 at 11:32
Particularly women! So do blokes, they want to have cold beer all the time for some reason.
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Follow Up By: The Bantam - Thursday, Apr 11, 2013 at 19:17

Thursday, Apr 11, 2013 at 19:17
Men most cerainaly put too much beer in the fridge.....If you have a proper fridge with some sort of efficiency and a reasonable power supply you only need to keep one days supply or less in the fridge, this could be as little as 2 cans for a reasonable drinker.

But women who have grown up with large fridges at home and not on camping...will fill a fridge with all sorts of things.....14 different types of condiments, 4 different types of salad dressing...little tubs of yogart in 6 different flavours and all sorts of other stuff.

Serioulsy.....some of us are old enough to remember when only the rich traveler had refrigeration and ice was often a bit hard to come by..and expensive...so the ice box was small and opened no more than 3 times a day.

When I was in scouts we had very little in the way of cold storage, in fact on the competitive camps it was not allowed.....we ate well enough.

I; not saying we need to travel like that.....but living like you do at home with huge fridges and mains power......gets very expensive on the road.

There is lots of stuff that does not require refrigeration.
Tinned goods, dried goods, heaps of stuff you eat every day.

about half of the fruit & veg we keep in the crisper will keep out of the fridge if it is kept only cool.

On the matter of alcohol.....lots of people used to carry spirits like rum and whiskey, because it required no refirgeration and took up less space.

Serioulst 2 people should be able to live out of a 30 litre fridge indefinitely......my brother and who ever is traveling with him does for 4 to 6 weeks at a time.....and he eats well.

FollowupID: 786351

Reply By: olcoolone - Thursday, Apr 11, 2013 at 07:36

Thursday, Apr 11, 2013 at 07:36
Have to agree with bantam regarding do you need so much cold storage....... If we are doing an extended trip of 2 to 3 weeks where we will not be able to restock we can get away with a 60lt fridge and at worst another 40 lt.

The only stuff you have to keep cold (not frozen) is some dairy, cryovaced meat and drinks.... everything else like bread, fruit and veg you can store in breathable plastic crates in a dry area.

The other option is review what you take and learn to eat differently when away.

Why do you need so much fridge and freezer space?
AnswerID: 508711

Reply By: Member - Ups and Downs - Thursday, Apr 11, 2013 at 08:45

Thursday, Apr 11, 2013 at 08:45

I agree with the others that you need a compressor fridge, ie Engel/Waeco. We have an Engel and a large Esky type fibreglass cooler.

We freeze whatever food we want, as well as 2 x 2 litre containers. These frozen containers go in to the ice-box, and the 2 old ones taken out and put back in the Engel to refreeze.

This works for us with the Esky food/drinks inc beer as cold as required.

AnswerID: 508718

Follow Up By: Member - John and Val - Thursday, Apr 11, 2013 at 12:10

Thursday, Apr 11, 2013 at 12:10
Hi David,

Have to agree with others about both your need for such a big volume of cold storage space and that a compressor type fridge will perform much better.

Regardless of what type of fridge or cool box you have you need to manage it carefully to get the best performance out of it. (Same probably goes for our fridges at home too, but with big volumes and reliable 240V power we mostly get into a habit of just cramming in whatever we want, opening and closing whenever we want etc without thinking about it.) On the road we have limited fridge space and often limited power availability so we need to compensate for that by being more careful about how we use our fridges.

At the start your journey load the fridge and coolboxes after they have been running and already cooled down. Put food in already cool or frozen. Choose as many foods as you can that dont rely on refrigeration. Prepare meals so that you dont have left-overs.

While travelling open your fridge and coolbox as infrequently as possible and for as short a time as possible. Rotate frozen stuff out of the freezer into the coolbox to thaw. Replace drinks in the morning so that they go into the fridge as cool as possible. Rotate a few bottles of water between the fridge freezer and the coolbox to keepthe latter cool. Use camp kitchens wherever possible to refreeze water containers to go into both fridge and coolbox. Shop as you go to minimise the amount of food that you carry from home and/or vacuum seal food to avoid the need for keeping food frozen. And so on...

Good luck


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Follow Up By: Member - John and Val - Thursday, Apr 11, 2013 at 12:14

Thursday, Apr 11, 2013 at 12:14
David, you might also find John blog on Electricity for camping (link is here) useful.


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Reply By: Motherhen - Thursday, Apr 11, 2013 at 12:58

Thursday, Apr 11, 2013 at 12:58
Hi David

Unless you have medical needs, it is easy to manage with little or no refrigeration. We all used to camp that way in the past.

If you really need supplementary refrigeration, I suggest getting a car fridge type of compressor fridge eg Engel. These top loading fridges are power efficient and can be used when really needed and turned off in between. They can be run as a fridge or as a freezer giving you further flexibility. We have run a 30 litre Engel from an 80 w solar panel and one 100 a/h battery. If the battery power goes too low at night, the controller shuts the fridge off, and as it is not being opened during the night, it doesn't warm up unduly.


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Reply By: Member - Robert R1 (SA) - Thursday, Apr 11, 2013 at 14:46

Thursday, Apr 11, 2013 at 14:46
David W28,

I would expect a second 3-way fridge would run off gas okay but it would be a huge load for your vehicle to run two 3-ways when you are driving. I would suggest a compressor fridge like a Waeco or the like. That way you don't need a lot of solar to keep it running while in camp. Depending on the weather etc. you would use between 20 and 40 Ah per day as a fridge. I use two fridges now, one as a fridge and the other as a freezer. I tried the esky for years but it is difficult getting good ice. Most of the ice is half water when you buy it and lasts about a day. If you are camped away from a town then you have a drive every day for more ice. It becomes annoying and expensive. I got sick of vegies and fruit going off in hot climates so I installed extra solar and bought a second fridge.

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Reply By: Dust-Devil - Thursday, Apr 11, 2013 at 18:51

Thursday, Apr 11, 2013 at 18:51
Hello David.

I have been watching this thread since it started and observed that the 'usual suspects' were there immediately to tell you how to go about your business and not answer the question that you asked i.e. How do I power more cold storage.

Personally I couldn't care less if you wanted/needed a 40ft Refrigerated Container to accompany you on you travels to the Bungles, Kakadu, CSR etc etc. Thats your business, so I'll have a go at answering your question.

(1) You already have a 3 way fridge, unless you are at a powered site somewhere forget about running it on 12V or 240v via an inverter. You will struggle to keep a power supply up to it unless you run a a generator.

As someone else stated these type of fridges work excellently on gas, so good in fact that I always run our large 3way fridge in our caravan on gas whether on a power site or not. My wife is always complaining that it freezes 'things' on the recommended Temp settings. Easy fixed, just turn it down a tad.

I don't and would never recommend to anyone to run a 3way refrigerator on 12V or on 240V via an inverter unless they had the mother of all Battery Packs and access to a generator to recharge same on a daily basis.

Suggested Solution: have a look at carrying more gas. 9kg bottles are the go.

(2) Obtain an 12V compressor fridge similar to a Engel 60L. One that draws no more than 5amps. You can use these as a Fridge/freezer and they are 12/240V.

See link:Engel Compressor Type Refrigerator.

How do you power such a device on 12V whilst prolonged free camping:

(i) Generator and/or battery storage

Run it as 240v into a Bat Charger (eg CETEK 25) through batteries to 12v Fridge (not the 3way way fridge)

Requires its own fuel, normally petrol.

(ii) Vehicle (static running) and battery storage

In-efficient way of doing business, however know people who do this. Doesn't do the vehicle a power of good.

Have to factor in extra fuel for the vehicle to do this.

(iii) Solar and battery storage.

Requires Solar panels and a solar regulator of some kind, large enough to run the extra refrigeration during the day as well as charge the batteries from the previous nights usage.

To do this you run the solar pwr through one of these doovers. Link:Redarc BCDC1240

When your traveling it will run off the vehicle Alternator, charging the batteries and running the extra 12V fridge. Not the 3 way Fridge. (why?? I'll explain below)

When static it has a MPPT solar regulator/facility that will charge the batteries and run the extra fridge during the day for nothing via the good old Sun.

This is the way I do it.

(3) Esky - only good if you have got a Ice supply.


(a) My caravan is a Jayco and Jayco as far as I am aware always use a magic 'black box' to run the 240V and 12V supply through.

Suffice to say, when traveling the 3way fridge is wired to the 'black box' so that it only draws a 12V source from the vehicle via a dedicated cable from the 'Black box' to the vehicle. It has no facility to charge the batteries via the 'Black Box' whilst traveling.

I use a Anderson Plug on my vehicle that splits into two Anderson Plugs. One for the dedicated 3way fridge cable and one to the Redarc BCBD1240.

This way I always arrive at destination with the auxiliary 70L 12v compressor refrigerator/freezer perfect, caravan batteries fully charged and the 3 way fridge holding the same chill factor as when we departed.

(b) On arrival at free camping site the 3way fridge is immediately switched to LPG, the solar panel is set up for maximum output (usually 7-10 amps depending on cloud) and all is good.

For me, the one solar panel via the BCDC1240 is more than enough to top up two 100AH batteries and run that auxilliary 12V compressor Fridge/freezer.

(c) The more you keep the access to any fridge to a minimum the less it needs to run to maintain the set temp.

My Aux Fridge pulls approx 5amps an hour, however doesn't run continuously for that hour .

If you ever decide to purchase the Redarc BCDC1240, let me know as there is a place thats sells them for $459 with free delivery.

Some one else may know of a cheaper source.

Hope this helps you


AnswerID: 508763

Follow Up By: Dust-Devil - Thursday, Apr 11, 2013 at 19:08

Thursday, Apr 11, 2013 at 19:08
That should be $415 not $459 for the BCDC1240
FollowupID: 786348

Follow Up By: Happy Frank - Thursday, Apr 11, 2013 at 20:01

Thursday, Apr 11, 2013 at 20:01
Good onya DD for trying to answer the question instead of saying "do it my way"
FollowupID: 786360

Follow Up By: oldtrack123 - Saturday, Apr 13, 2013 at 12:47

Saturday, Apr 13, 2013 at 12:47
Happy Frank posted:
Good onya DD for trying to answer the question instead of saying "do it my way"

FollowupID: 786526

Follow Up By: David W28 - Monday, Apr 15, 2013 at 18:35

Monday, Apr 15, 2013 at 18:35
Thankyou Dust-Devil, After the weekend and doing some thinking. Would it be possible to set a 12v socket on my van to run a 30-40lt Freezer or Fridge-freezer through my (2)115amp batteries off a 160 or 200watt solar panel-s that has 30-40amp regulator on panels.
My 3way fridge runs only on gas. so the freezer and lights which i will change to LD will run off the batteries. Only run lights on power at c'van parks. This is to freeze roasts, bbq packs, marinade Chicken and others. Hope you can help. Hope you can help,

regards David.
FollowupID: 786759

Follow Up By: Dust-Devil - Wednesday, Apr 17, 2013 at 03:08

Wednesday, Apr 17, 2013 at 03:08

(1) You have a Chit load of battery power there, which, from you description/s is only going to power lights, and a Aux fridge/freezer of some sort and maybe some electronic device/s charging of some sort.

(Please advise if I have got this wrong and/or you have some other undisclosed 12V items that you run of the 2 Trojans.)

That is the only power draw you are going to have on that battery bank in a 24hr period, during which you intend to harness the sun for at least 8 hrs to replace the power used.

Depending on what sort of 12V lights you're using the power
consumed by them on a daily basis should be acceptable and will decrease when you install LED's.

(2) If for example you add a 12V Fridge/Freezer such as the Engel described in my reply above, you will be adding a device that draws 5amps per hour from the batteries if run continuously.

To use it effectively as a Freezer or Fridge for that matter, you should load it and get it down to the required Freezing point 24 hrs prior to travel.

(a) This gives you 24hrs notice as to whether or not the sucker is going to work correctly - Yes! these items do decide to break down at the most inopportune times.

(b) Only requires the vehicle and/or battery bank to maintain the Chill Point that you have set. This means it will not be running continuously for an 'amp hour', rather in short cycles on and longer cycles off.

(c) Because you intend to use it in Freezer mode, it will only be opened on the odd occasion which will also help in reducing the amount of times it cycles on during a 'amp hour'.


Fridge/Freezer needs to be run off of the battery bank with its own dedicated, fused, 6mm (4.2mmsq) cable with either a Merit Point Plug (Narva) or a Anderson Plug.

How you do this is up to you. I have fitted a 12V Merit Socket to my caravan that has an external exit, so that the Aux Fridge/Freezer can be placed outside if preferred. Also have them inside. All of the these cables are 6mm, fused and wired direct to battery bank.


I had problems with maintaining the 2 x 100 Ahr batteries in my caravan on maximum charge when traveling for a number of reasons.

I solved them all by purchasing and installing a Redarc BCDC1240. The vehicle supplies 12V to the BCDC1240 via a 4 B&S (4AWG) gauge twin cable and Anderson Plugs at the Tow vehicle, and then outputs 40Amps of whatever Voltage is needed. ie 12V - 14.3V to the Battery Bank

My solar panel used to be used in three different traveling setups and as such is a highly portable item. It is a free standing 120 watt panel that runs to a mobile MPPT regulator via a twin 6mm cable, then DIRECT into the battery bank again via a fused 6mm twin cable

This setup allows me to run Lights, water pump, phone & other electronic items (charging), Satellite TV & Aux Fridge/Freezer without any problems. Add a fan during warm weather and a Diesel Heater in cold weather.

I cant comment on your Solar Regulator, however from what you say I assume that it puts out in excess of 8amps which mine does(on a nice sunny day).

If you connect your solar panel/s DIRECT to your battery with a fused 6mm twin cable from the Regulator, all should be good.

You can do this via a Merit Point (Plug and socket) as I described above. Link:Narva Merit Plugs and Sockets

Hope this covers your concerns.



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Follow Up By: David W28 - Wednesday, Apr 17, 2013 at 14:37

Wednesday, Apr 17, 2013 at 14:37
Thanx DD for your answering my ?'s this will be a great help into what i need to do. much appreciated, Regards David.
FollowupID: 786968

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