Running two Fridges

Submitted: Monday, May 05, 2008 at 22:14
ThreadID: 57318 Views:3400 Replies:6 FollowUps:6
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Hi all last question for tonight can you run two fridges at the same time with out putting too much strain on the battery
I have two plugs wired back to the aux. battery one fridge is an Engel 40ltr the other is a Waeco 80ltr the battery is a Trojan deep cycle
Thanks in Advance

Matt & Julie

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Reply By: Member - John - Monday, May 05, 2008 at 22:19

Monday, May 05, 2008 at 22:19
what size battery and for how long and in what temp?
John and Jan

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AnswerID: 302237

Reply By: Member - Phillip S (WA) - Monday, May 05, 2008 at 22:23

Monday, May 05, 2008 at 22:23
I run two fridges all the time, 1x60L and 1x50L Waeco's...when I'm travelling....I have two is a cranker only and the other is a deep cycle /crank as well....the 50L is run as a freezer....with two fridges I get two days without the engine running.....four days with just one fridge...been doing it for a long time now...and will contiue to do so...cheers Phil
AnswerID: 302238

Follow Up By: Member - Phillip S (WA) - Monday, May 05, 2008 at 22:25

Monday, May 05, 2008 at 22:25
ps...the cranker IS only for the criuser....the other for the fridges and lights and inverter and etc etc etc
FollowupID: 568293

Follow Up By: Member - Mark E (VIC) - Monday, May 05, 2008 at 23:04

Monday, May 05, 2008 at 23:04

You must have an amazing Deep Cycle Battery!!! My rough calculations:

1 x 60l fridge (as fridge) minimum 25AH/Day in moderate climate
1 x 50l fridge (as freezer) minimum 40AH/Day in moderate climate

Above totals a minimum of 65AH/Day without running anything else and that is a very conservative estimate. Two days would see 130AH used. Dunno about the lights, inverter and etc etc etc......

I have the biggest AGM I can fit in the 105 series (had to modify the tray) and it is 120AH. I do run it down to 80% occasionally which is about 85AH or so. and I can get a max of 4 days with the Autofridge running eutectic mode in moderate climate.

Can you tell us how you do it? Do you run them till the battery is dead flat or have you a low voltage cutout? I would love to get more power out of my battery setup without damaging the batteries.


FollowupID: 568299

Follow Up By: al - Tuesday, May 06, 2008 at 11:58

Tuesday, May 06, 2008 at 11:58
i run two 39 litre engle fridges plus other accessorries i get 2 days out of my battery. battery has 90 amp written on it. it is a super cheap lead acid deep cycle battery we've had it for 3 years still working. we travel a good part of the year in northern part of oz. working and enjoying so used constantly. i'm not it to amp hour usage not that interested.
when it breaks down i'll get another. why are u concerned about amp useage the battery will tell when it is flat or the fridge stops far hasn't happened.
have a nice day
FollowupID: 568351

Follow Up By: Member - Mark E (VIC) - Tuesday, May 06, 2008 at 14:38

Tuesday, May 06, 2008 at 14:38

Not really that fussed, but over the years I have spent more than my fair share on replacing batteries and over the past few years have been looking into ways of not stuffing them, as most battery failures are through operator error and poor maintenance as were all of mine.

Clearly with your setup, your battery will be close to flattened at the end of two days and imagine won't last that long (though 3 years with this treatment is keep doing it and buying those Supercheap batteries as they must be good!)

I also agree, when it breaks down I'll get another too, but preferably when not a week away from civilisation with a months meat in the fridge!!!


FollowupID: 568364

Follow Up By: Member - Phillip S (WA) - Tuesday, May 06, 2008 at 22:48

Tuesday, May 06, 2008 at 22:48
As I said being doing it now for a while....I listen to you guys and it amazes me how you calculate this and that etc etc....I just do it and it works for me.... soooooooooooo....if it ain't broke why fix works for me. The second battery has the normal posts and two studs as well so that you can attach a few cost a few bob too....I used to have two big crankers but this set up is a lot better.
FollowupID: 568462

Reply By: Crackles - Monday, May 05, 2008 at 22:39

Monday, May 05, 2008 at 22:39
Yes you can run 2 fridges at once without hurting the battery. Similar load to running one driving light. Of course the next question is invariably how long will it last & that as John has eluded to will depend on the size of the Trojan & the temperature. Suggest a 100ah battery only good enough for around 12 to 20 hours at best running one as a freezer & the other as a fridge so good for overnight stops but not much more.
Cheers Craig.............
AnswerID: 302242

Reply By: The Rambler( W.A.) - Monday, May 05, 2008 at 23:08

Monday, May 05, 2008 at 23:08
Ithink Crackles is spot on.Irun a 40l Engel as a fridge and a 32 Engel as a freezer plus a few lights and with a 115a/hr battery I look at getting about 18hrs on an overnigt stop.
AnswerID: 302246

Follow Up By: mowing - Tuesday, May 06, 2008 at 00:14

Tuesday, May 06, 2008 at 00:14
Yep my vote is with crackles. The most efficient fridge/freezer set up as one fridge and the other freezer will use around 65+ amphrs without sucking it too low.

FollowupID: 568303

Reply By: Motherhen - Monday, May 05, 2008 at 23:15

Monday, May 05, 2008 at 23:15
Hi Matt & Julie

We are going to try something similar. When we went on holiday last year we ran a 40 litre Engel and reading lights off the deep cycle battery. I'm not sure what size - it is what we got from the local dealer and the invoice doesn't give any details. It charges from one 80 w solar panel, and the battery read full charge most of the time. We are going to try an additional 30 litre Engel as a freezer and see how it goes.


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AnswerID: 302249

Reply By: In Good Time - Tuesday, May 06, 2008 at 08:59

Tuesday, May 06, 2008 at 08:59
We run an Auto Fridge and 3 way 12/240/gas.
Have found this to work very well. Auto fridge is operaterated as a freezer with a 60w solar panal to backup when required. 3 way is operated on gas once stopped for the night. This system has enabled us to stop camped in the one place for extended periods and not have to be concerned about batteries. We turn the freeze (auto fridge) of at night and it still holds at approximately -4 to -6 in the morning. 9kg gas bottle on the 3 way will last approximately 4 to 5 weeks depending on temperature.
AnswerID: 302278

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