I've got a 85amh leisure battery. It doesn't last a day on a 50w cooler. I was thinking of getting a second one so that I could charge one, whilst using the other.
I have heard about a split charger on the car (apparently will cost about £50 to fit)but dont know how long it will take to charge a battery up. Does anyone know how much charge I will put back into the battery if I have it in the car for a hours worth of driving? Or are there better ways to charge a leisure battery (other than sneaking a battery charger onto someones mains)?
Try not to baffle me with the e=mc2 stuff, just rough hours worth of use or idiots guide stuff.
Many thanks
Ian117
Hi and welcome ,
i agree with oldham , Coolboxes are just not meant to be run on batteries when the engines not going.
Youd be better off with a 3 way fridge and run it on gas,if ehu is not an option. the combicools are about £150 and will work much better than an electic coolbox too.
£50 for a split charger plus the cost of another leisure battery , which still won't power the coolbox for long periods is just a waste of money .
Hi Ian
Got to agree with all comments on coolbox, no good on 12v.
I have just come back from a 3 week trip to France with no EHU, we had 3 way fridge on gas essential for cold beers, and 12v leisure battery for lighting and satellite TV only for news & English radio stations.
How I charge mine is when out for the day I plug a split charge relay into cigar lighter of car connected to leisure battery and it does it automaticlly, but bear in mind I worked as a towbar fitter so know what I'm doing.
Regarding the price of split charge relays have a look here only £9.95 from Towsure.
Somewhere else on the site people were talking about just running the car for 5 minutes with croc clips on the car battery, which would out-perform most solar panels for a day!
That's a lot of drain on a battery though - are you leaving it all in your nice _warm_ tent during the day?!
Quote: Originally posted by riddles on 25/6/2009
Somewhere else on the site people were talking about just running the car for 5 minutes with croc clips on the car battery, which would out-perform most solar panels for a day!
That's interesting, is that true? We're looking at a battery solution to power run the laptops, phones, cameras etc and poss the 3 way fridge if there was enough power. we've been looking at a solar panel but it's still a bit too priceY
given that it's a bit of a luxury and we don't actually need power. Maybe we should just be looking at charging a leisure battery from the car?
When you start vehicle you use battery power, this needs to be replaced before any charge available for second battery. Will tick over be sufficient for charging two batteries and if so how long for two fully charged batteries.
Working on the principle that you using the car as a portable generator are you not going down that line, via a different route.
Expect running cars on site threads on par with generator threads.
For high usage EHU is the way to go, for low usage Solar. Split charging,or asking site to charge.
The power required to start the car is well within a decent batteries limits, Even if you disconnect the alternator you could be sitting there for an hour starting and restarting the engine.
£50 - £100 for a 12watt/1amp solar panel. This would take 4 or 5 times longer to charge the battery than a cooler drains it. 85 hours of full sunshine to recharge the battery. 10 days worth??
A cars alternator will put out 50 amps +
In theory you could replace the charge from starting the car and fully charge the leisure battery in under 2 hours. I dont think a leisure battery would take kindly to being charged from flat to full in under 2 hours though. They are best charged slowly 5/8 amps will see it lasting for years to come.
Ok I know EHU is the answer but was trying to go without on principle, as I am in a tent.
I was also trying desperately to fight getting a gas bottle as have petrol stove and lantern.
These 13w solar panels briefcases - would they really be able to recharge a leisure battery and if so how many hours are you looking at. I was lead to believe they were only good for topping up your battery if left for long periods
Thank you all for responding I am loving this forum for being helpful and friendly
just running a car on idle with a standard alternator, would take hours to charge two battery's, you couls upgrade your alternator but you still have the problem of running your car for some time annoying people aroung you.
solar panels are good but i think your using to much power for a cheapish panel to cope with,
These 13w solar panels briefcases - would they really be able to recharge a leisure battery and if so how many hours are you looking at. I was lead to believe they were only good for topping up your battery if left for long periods
To charge a flat battery 1 hour for each amp, providing you get full sun.. as i mentioned above 85 hours of full sun to charge one fully. 8 days?? to put back the charge you used in less than 24 hours.
A 13w solar panel will give around 4AH per day in the UK in summer. An 85AH battery gives about 40Ah useable energy.
40/4 = 10 days!
A car alternator will not give the full rated amps in any sensible configuration unless you fit a sophisticated (and very expensive, 100s of £s) charge controller.
Most split charge relays are rated at around 10A - if you were getting the full charge you'd need some substantial wiring! The modern fitment voltage sensing ones will not kick in until the car battery is well charged. This is fine if you can load the battery in the boot and are doing a fair bit of driving each day - be sensible and it's an excellent way of keeping the battery charged.
If you just use jump leads car - leisure battery you will initially be taking juice from the car battery (it's got to come from somewhere at the end of the day). I believe you'd need to run for a lot longer than 5 minutes to get a sensible charge.
At the end of the day though things like fridges and heaters need mains 'leccy or gas.
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Topic: Charging Leisure battery while in tent
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