How long should a coolbox run off a leisure battery for?

Strettyp

Strettyp

Senior Member
VIP Member
T6 Guru
I've got a 19 plate LWB T6 and opted for the factory fit heater which came with the leisure battery under the passenger seat - I only sleep in it a night at a time after hiking but would like to leave my cool-box plugged in while parked up for the day to keep some food and er, refreshments cool all day - I've been told that the cigarette lighter draws from the leisure battery so could I leave the cool-box running all day without killing it? I only need it to run for around 16 hours during the day and would pack with icepacks at the start of the day, so that when I got back from the days exertions my sausages would be fresh and my beer cold.

It's this one from halfords and has the following drain "Wattage is 42W. Draw in amps is approximately 3.5A from a 12V supply"

Halfords 40 Litre Mains and 12V & 24V Electric Coolbox | Halfords UK

I'd normally just give it a go and see what happend but my father in law (expert in literally everything) tells me that it would ruin the battery if I drained the charge to nothing.

Anyone got any ideas?

Thanks in advance :thumbsup:
 
On the battery, there will be an amp hour rating (Ah), lets assume for round numbers is 100Ah, 100/3.5 = 28 hours. You will need to check your battery and substitute '100' with the correct number. It may be the unit only draws 3.5A when 'cooling' if it has any sort of temperature regulation when it gets down to the required temperature it may well reduce its current draw thus prolonging the possible run time.

I'm not sure if there is any battery monitoring on the factory fit leisure battery, ideally it is wise to have a device monitoring the battery state of charge and 'turn off' any loads before the battery is fully discharged to prevent damage to the battery.

Finally, you need to be sure the cigarette is connected to the leisure battery...it would not be wise to run such a load of the main engine battery as the likelihood, when partly discharged it wouldn't have the guts to crank the engine.
 
I might be missing something here.... I usually am...

But if the spec of the unit is a 3.5A draw from a 12V supply and he has a 110Ah leisure battery, then wont that give him approximately 30 hours (30x3.5=105) before he completely kills the battery..? So a 16 hour use from a fully charged battery would probably be OK..?

Untitled1.jpg
 
You'll probably find that 3.5a/h is once the coolbox is down to temperature, It will draw a lot more than 3.5a. You'll be lucky to get 5 hours from it. Coolboxes are very inefficient and they can only cool so many degrees below ambient so if it's warm outside it'll be working even harder. Also remember that you should only discharge your battery to 50% to avoid damaging it.
 
@Deaky brill thanks - he's usually right which is good (if annoying!) I guess - presumably there's no issue it being plugged in while driving but then need to unplug when parking up? I would be getting it down to temperature before plugging in with the icepacks - it says it can get down to ambient -18 but in an indium grey van in the sun that could still be warm....

@sparkzer - I have got a jobby with an additional 12v socket, two USB sockets a a voltage reading that I am going to connect to the leisure battery but annoyingly need to remove the passenger seat to do - going to sort that this afternoon.

@JasonW that's what I worked out but the FiL disagreed

is a better cooling solution the best option - any ideas?
 
thank you - I'll have a look at the solar panel threads and see what's what
 
I'm sure someone will have a cheaper solution if your on a budget...

I know my 250 Watt panel on a sunny day can put between 20-25Amps and hour back into my battery....

So something around the 100-150W mark should be plenty to just top up your leisure battery with the coolbox attached..... and would be cheaper for you...
 
An additional point, there is nothing stopping you plugging it in to the mains and loading it up at home...then transferring to the van 'ready cooled' therefore its only got to maintain the temperature..

I've a 130W solar panel, 120Ah battery and a draw fridge...the fridge draws next to nothing when down to the required temp.
 
I don't mind buying the right thing as I'm of the "buy cheap, buy twice" mindset - the missus bought me the coolbox for my birthday last year and now it's getting warmer would like to use it - my camping is all very ad-hoc as I need to keep the van empty during the week so just chuck bed, cooker and water container in the back and off I go

thanks everyone for all the help - this place is a goldmine information wise
 
Just to back up what everyone else has said, Peltier coolboxes are really greedy and inefficient, and you shouldn't take more than 50% of a Pb battery's capacity.
Some coolboxes have a thermostat and will coast once down to temperature, others are permanently running so pre-cooling doesnt reduce its draw.
If yours doesnt, its easy to add one. Roo has a timer on his, it powers for an hour then switches off, which seemed a good compromise at the time, not critical now as he has solar.
Overnight, a properly insulated coolbox shouldnt need to be on, if you're not opening it, it should stay cold - and you dont want the fan noise overnight ;)

There are also compressor and gas-cartridge coolboxes, significantly more expensive but could be an answer

Cheers
Phil
 
If it’s only a day or so, if it’s well packed with ice and presumably reasonably insulated then I would think it’s probably going to be reasonably cool without any active cooling at all? Plus, you can happily have it plugged in to the starter 12v whilst driving to your destination as it’ll be driven by the alternator.
 
Get a compressor cool box like a mobicool fr40. A peltier based one will draw circa 5amps continuously. Compressor very efficient and as good as a proper fridge.
 
As above.

Electric element cool boxes draw around 6A. (Will kill a 100ah battery in 1 day)

A compressor fridge is the way to go.

Unless you get 100w solar to offset the draw.

Here a quick vid I done years ago.... but shows cooler box loads and 12v and via 240 inverter.


.
 
The Mobicool MFC32 compressor coolbox for example is rated at 83kwh per year.
That works out to 10 watts average, less than an amp (average) at 12v - a fraction of a typical Peltier coolbox. No contest! :)
 
Last edited by a moderator:
Just to throw another angle from someone i follow on YT...Probably not something you will be interested for occasional use, but interesting none the less.


Your basically offsetting the efficiency of a compressor fridge off the inefficiency of an inverter.
 
IMG_7674.jpeg
I replaced the Halfords cool box with a Vitrifrigo compressor fridge.
The Halfords fridge would drain my battery in a few hours.
The Vitrifrigo runs easily for 2-3 days off my leisure battery. I don't have solar.

My advice is buy a compressor fridge, they are brilliant.
 
You must log in or register to reply here.

Similar threads

S
Amp off leisure battery
Replies
2
Views
251
snoop6060
S
Ayjay
Powering a Coolbox - 12V or 240V?
Replies
8
Views
2K
Ayjay
Ayjay
CrazyDunk
Solar Install & Mystery Vehicle Battery Drain
Replies
7
Views
511
CrazyDunk
CrazyDunk
P
Leisure battery install has raised a couple of fault codes.
Replies
3
Views
645
Pistol-pete67
P
d8smt
Clayton LPS I 12vDC current drain - ideas/advice pls?
Replies
10
Views
587
d8smt
d8smt
Back
Top