what size thumper/solar will run 40lt engel permanently?

we are setting off on a year or so trip around oz (in a HZJ75 Landcruiser) and need to set up a duel battery and soar system to run our 40lt fridge permanently. Where do we start? Any advice with what size solar? or in car duel battery, or portable system (ie:thumper)?
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Reply By: Muddy.au - Sunday, Mar 27, 2011 at 19:58

Sunday, Mar 27, 2011 at 19:58
It will depend on how many days you plan on stopping at each location, I run a 120 amp/hour Full River dual battery set up in my 100 series, with a 60lt Engel combo but only spend 2 days max with out traveling to recharge but also run 12v lighting.
AnswerID: 449389

Reply By: Member - Neil G (VIC) - Sunday, Mar 27, 2011 at 20:46

Sunday, Mar 27, 2011 at 20:46
Hi Donna,
We have a set up that does what you want and works verywell for us.
We have 40 litre Engel set up in the back seat area of our 60 series Landcruiser and mostly use it as a freezer on our extended trips. It stays at between -10 and
-15 for all of the time we are away.(sometimes several months at a time).
To run it we have an auxilary battery of 120AH ( Full River Deep Cycle AGM) and an 80 watt Solar panel mounted on the roof of the car. This means that the battery is topped up every time we use the car and if we don't use it much the panel keeps it charged.
Hope this helps and good luck with your planning. Let us know if you need any more details.

AnswerID: 449401

Reply By: Motherhen - Sunday, Mar 27, 2011 at 20:58

Sunday, Mar 27, 2011 at 20:58
We use an 80 w panel with Prostar controller and a 100 a/h battery to run the 40 litre Engel. It sometimes switches off at night. While this panel worked for us in good weather originally as a portable for a camper running an upright Engel and lights, you would be better to get the largest panel you can accommodate eg 130 w when setting it up and the largest battery you can fit in eg 120 a/hs. 80 w was the norm when we got our first panel.


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AnswerID: 449404

Reply By: Sand Man (SA) - Sunday, Mar 27, 2011 at 21:34

Sunday, Mar 27, 2011 at 21:34

Your question is a bit ambiguous as to the "permanent" requirement.

If you have a good dual battery setup, the auxiliary battery will be charged by the vehicle alternator and that may be all you need if you are travelling daily.

If however, you intend to be stationary for a couple of days or more, the requirements change.

I have a 75Ah thumper running my 40 litre Engel and is charged by the vehicle alternator when on the move. I also have an 80 watt folding solar panel array to add a charge to the portable battery system when stationary and have found this setup to be adequate for my needs.

When I upgraded my vehicle I added a new auxiliary battery system consisting of a Flyer battery pack containing a 100Ah AGM battery and also capable of being charged by the alternator.

The fridge is connected to the Flyer while travelling, then to the Thumper when camping, with the solar panels connected to add a charge back into the battery pack during daylight hours. The Flyer then is available as a back up battery system should inclement weather negate the input of the solar panels.

There is no "perfect" system as environmental conditions change, but as a general minimum for a 40 litre fridge on "fridge" setting (not freezer), an 80 watt solar panel should be adequate to put in as much charge to the battery during daylight hours, as the fridge draws from the battery over a 24 hour period.

A modern 40 litre fridge such as the Engel will run at a maximum of 2.5 amps per hour (usually somewhat less) and an 80 watt solar panel is capable of putting back around 5 amps per hour in good sunny conditions.


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AnswerID: 449412

Reply By: S Paul - VIC - Sunday, Mar 27, 2011 at 23:07

Sunday, Mar 27, 2011 at 23:07
I have a 140 watt panel permanently mounted on my Jeep's roof it charges via a MPPT reg the 100 aH AGM in the rear which runs a Waeco CF 50 Litre fridge -
No dual battery set up and I haven't flattened the battery yet - touchwood.
Thumpers are very good but you would save money buying a decent AGM deep cycle battery and a battery box to put it in - That extra cash could be used to beef up the Solar ...



AnswerID: 449423

Reply By: Gossy - Monday, Mar 28, 2011 at 12:46

Monday, Mar 28, 2011 at 12:46
if you mean to have the solar connected to the batter all the time when you are not driving then any size will do. I have a 50 litre running on a 50amp/hr deep cycle and that runs 'forever' as long as the solar is connected at the same time. What you lose at night time you get back during the day so if this is what you mean then you don't need to buy a large battery.
AnswerID: 449457

Reply By: Member - John and Val - Monday, Mar 28, 2011 at 13:03

Monday, Mar 28, 2011 at 13:03
Hi Donna,

Have a look here at our Electricity for Camping Blog. Theres a bit of info there to help get you started.


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AnswerID: 449459

Reply By: Member - Geoff H (Q - Monday, Mar 28, 2011 at 16:34

Monday, Mar 28, 2011 at 16:34
We run a 105 A/h battery and if it gets low (only happened once because we normally drive somewhere each couple of day) we run the Prado for half an hour or so.

It only uses 4 litres an hour when idling, and punches out 100 amps.

Saves buying a Gen set, carrying unleaded or setting up a solar system.

We like to travel light and have a couple of uses for each item. And I can buy lots of beer for the price of a Gen set or Solar system.

AnswerID: 449474

Reply By: Torza - Monday, Mar 28, 2011 at 20:49

Monday, Mar 28, 2011 at 20:49
We have a 105A/H deep cycle battery and a 170Wfolding solar panel and this runs a 40 litre Engel on freeze and 115 litre (give or take) Eva Kool which runs on 1/2 fridge, 1/2 freezer. We had a few problems until we learnt how to tweak the Eva Kool to get the best out of it but now it works like a charm. I think you do need a dual battery system.

Hope this helsp too and enjoy your travels
AnswerID: 449510

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