# G'Mornin' Campers!



## unclejonboy (May 15, 2011)

Off camping and the only thing I miss about leaving civilisation behind is keeping stuff cool...Don't want lights cookers radios cells laptops but do enjoy the odd cold beer and just stopping stuff going off. I refuse to use the prepped meals or stuff in a can, so I've seen a folding portable solar panel that gives 13 -15 watts... I know that won't run the 12v cool box at 4 amps, thats 48 watts isn't it...watts = volts x amps? Does that work the other way round so that a twelve volt 12-13 watt output is one amp??' is one amp enough to trickle charge a battery like it claims on the box?

Waddya think if I run the cooler off a spare battery and keep the panel linked up to the battery all day and disconnect the coolbox from the battery from time to time is it going to make the battery last significantly longer?. .... the cooler will drain a standard car battery in four or five hours....??? any ideas or electrickery theorists out there? UJB


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## tixntox (Jul 17, 2009)

Just wrap your cans or bottles in a wet T towel. As the water evaporates, it cools the drink. Grand dad used this trick in the desert! :notworthy:

Mike


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## jasonm (Nov 22, 2003)

We had this 'issue' a cool box running off our leisure ( extra ) battery, it was drained in a few hours, I guess its a matter of matching the charge to the drain with your panel , buy the largest rated one you can afford, they get quite pricey for the big ones ...

Maplin do a range, also try 'justKampers' ....


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## mel (Dec 6, 2006)

First off, the current drain on the battery for an electric coolbox is just horrendous, 4A on a 100Ampere hour battery will easily drain one in four hours or so, and then you get into deformed plates and permanent destruction in the battery cells as the output voltage drops belwo 11 or so volts. :dontgetit:

Next, although a 12/15W panel will in theory deliver 1A at twelve volts, if you check the volts coming out of one, it'll be in the region of around 18V to allow the panel to charge the battery, and the battery itself "regulates" the charge voltage to around 13V by being the load on the panel. For that reason, the easiest panels to use are around 12/15W - you don't need a (relatively) sophisticated electronic charge controller module to prevent the battery overcharging and "boiling off" :yes:

So a regular 15W solar panel will indeed *trickle charge* a twelve volt battery that is already in good or well charged condition as a "top-up" but is immediately struggling to charge a drained battery, especially given daylight hours in the UK - and lack of sun - the charge volts and current will be reduced on a dull or wet day, although is still there.

So if you opt for a really large panel, there will need to be a charge controller - either built-in, or as a separate item - to reduce the charge rate as the battery comes up to a "full" condition, just like in a good quality car battery charger from the mains.

If you're camping on a regular site, the best option is likely a Mains Supply Unit (with safety trips) and use a "three-way fridge" runs off gas, leccy or twelve volts, but not a great option if you are slim or back-pack camping. OTOH you can also run other stuff (decent lights etc.,) off the mains unit 

There used to be coolers that worked quite well simply by pouring water into a shallow depression on the top of a small fridge like insulated box, but I'm damned if I can remember the name of them - it's an ldman: age thing! Try asking at a caravan/camping shop to see if they're still made, had one for years, works on the evaporation principle.

HTH a bit!

The Sequined Avenger


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## unclejonboy (May 15, 2011)

Thanks for that comprehensive reply... I am off tomorrow and as the panels are on an end of season offer I think I 'll gamble a hundred beer tokens... If it doesn't work out for camping it's always there for other stuff...I'll post the results next week if I haven't had a breakdown caused by warm beer and runny butter... I am in Supersunny portugal so the sunlight hours thing isn't a problem, but that also means 40Âº in the shade...on the boat at the biggest freshwater artificial lake in Yurp .... Tanx agen UJB


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## a6cjn (Oct 29, 2009)

One thing I would check is the spec of your cool box as they are not designed to be run continuously.

It says no more than eight hours on the one I have.

Chris


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## Roger the Dodger (Oct 5, 2009)

Yeah...mine too...I wasn't aware of that when we bought a cool box for camping... usually take the trailer tent to a site with electric hook up...so in the end I got one of those small Husky fridges. They usually come branded with a famous name (Coke, Stella, Guiness etc) but you can get plain ones, and they are a proper fridge, not just a cooler. It easily fits in the locker box on the 'A' frame of the trailer.


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## SammieNasser (Mar 30, 2014)

mel said:


> First off, the current drain on the battery for an electric coolbox is just horrendous, 4A on a 100Ampere hour battery will easily drain one in four hours or so, and then you get into deformed plates and permanent destruction in the battery cells as the output voltage drops belwo 11 or so volts. :dontgetit:
> 
> Next, although a 12/15W panel will in theory deliver 1A at twelve volts, if you check the volts coming out of one, it'll be in the region of around 18V to allow the panel to charge the battery, and the battery itself "regulates" the charge voltage to around 13V by being the load on the panel. For that reason, the easiest panels to use are around 12/15W - you don't need a (relatively) sophisticated electronic charge controller module to prevent the battery overcharging and "boiling off" :yes:
> 
> ...


Really top quality solution.. Sorry for posting in bit old thread but I was facing similar issue with electrical system and now I will be able to sort it out..


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## oldnut (Mar 10, 2014)

SammieNasser said:


> mel said:
> 
> 
> > First off, the current drain on the battery for an electric coolbox is just horrendous, 4A on a 100Ampere hour battery will easily drain one in four hours or so, and then you get into deformed plates and permanent destruction in the battery cells as the output voltage drops belwo 11 or so volts. :dontgetit:
> ...


I think they were swamp coolers, used a lot in old American cars. I prefer a small wind turbine for charging while camping, I mean its always wet and windy!


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## SammieNasser (Mar 30, 2014)

SammieNasser said:


> mel said:
> 
> 
> > First off, the current drain on the battery for an electric coolbox is just horrendous, 4A on a 100Ampere hour battery will easily drain one in four hours or so, and then you get into deformed plates and permanent destruction in the battery cells as the output voltage drops belwo 11 or so volts. :dontgetit:
> ...


Problem got solved..It worked perfectly..


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