How long will a battery run a cool box?

[welland99]

I'm going on holiday next week with my W210 E280 and I plan to run one of those 12v cool boxes from the lighter socket in the boot.

Does anybody know, or know how to calculate, the most time I could run the cool box for without making the battery too flat to start the engine (if I run it with the engine switched off)?

The Cool box is rated at 50W.

Does the car have the in built ability to cut the power supply to the boot lighter socket before the battery goes flat?

If the battery did go flat, would it cause any complications in the car apart from the radio losing its code? Or could I just start it with jump leads and then carry on.

 

[bolide]

50 Watts means (approximately) a 4-amp draw. So an 80 AH battery will last (theoretically) 20 hours

It all depends on the state of your battery. Try it overnight one night - if it starts OK the next morning, and you run the car for a couple of hours each day, I am sure it'll be OK

Nick Froome

 

[verytalldave]

Or to look at it another way...............
Its roughly the same leaving ONE headlamp on.

How long would you estimate you could do that and leave enough reserve in the battery for the car to still start?
8 hours maybe is a reasonable time-scale before you get into the "will it or wont it start" scenario. Specially in summer when current drain on starting is less and batteries tend hold charge better.
Your car doesn't have the capability to switch off the power to the cool-box automatically before its runs the battery down too low for it to start. It will stay on until the battery is completely dead. Not a good thing to do as it can buckle the battery plates and render the battery permanently useless.
You could rig-up an home-made device which would switch off the power to the cool-box after a predetermined time to avoid total battery drain. It wouldn't be too difficult to do with a self-powered timer.

 

[RichardM]

You can buy cool boxes that have the protection built it, so they will cut off automatically when the voltage drops below a certain level.

 

[Dec]

Doesn’t a coo box consume power in the same way as a domestic fridge?
For example a fridge will run for 1 minute every 15 minutes so that’s 4 minutes per hour that it is consuming power.

Dec

 

[280gee]

Doesn’t a coo box consume power in the same way as a domestic fridge?
For example a fridge will run for 1 minute every 15 minutes so that’s 4 minutes per hour that it is consuming power.

Dec

Not for the types most easily available as they use a Peltier cooling device which runs continuously.

In the case of the far more expensive compressor type fridge/cool box then they will switch off after reaching the desired temperature.

I used a 50W cool box earlier this year in temps up to 30C but would not dare run it unless the engine was also running.
Perhaps just for a lunch stop or similar, say an hour or so, it would be alright. A lot depends on the health of your battery.

HTH

 

[BTB 500]

As above, they do draw power continuously and are really intended for use with the engine running.

Speaking of which ... is the boot socket permanently live anyway?

 

[whitenemesis]

As above, they do draw power continuously and are really intended for use with the engine running.

Speaking of which ... is the boot socket permanently live anyway?

Not on my S203

 

[flango]

I'm going on holiday next week with my W210 E280 and I plan to run one of those 12v cool boxes from the lighter socket in the boot.

Does anybody know, or know how to calculate, the most time I could run the cool box for without making the battery too flat to start the engine (if I run it with the engine switched off)?

The Cool box is rated at 50W.

Does the car have the in built ability to cut the power supply to the boot lighter socket before the battery goes flat?

If the battery did go flat, would it cause any complications in the car apart from the radio losing its code? Or could I just start it with jump leads and then carry on.

We used to do this when camping at race events and there is a couple of tricks to eek the most out of it. Before I answer in full will you have access to mains power where you will be staying I'm thinking electric hook up for camping etc or is there no mains acesss at all?

 

[rf065]

Does anybody know, or know how to calculate, the most time I could run the cool box for without making the battery too flat to start the engine (if I run it with the engine switched off)?

Do what I did, buy a Hella lead from cigarette lighter to cool box which cuts the power when it goes down to 11.8 volts.

I use mine for work & leave it plugged in 24 hours a day, no problems. I even leave it plugged in all weekend & have never had a flat battery.

Remember, good quality cool boxes are very well insulated & will keep everything cool many hours after they are switched off.

Russ

 

[whitenemesis]

So the socket is permanently live?

Mine only works with the key in

 

[BTB 500]

Do what I did, buy a Hella lead from cigarette lighter to cool box which cuts the power when it goes down to 11.8 volts.

That seems very low - 11.9V is normally considered fully discharged

 

[A210AMG]

Hello

I used one in my ML and used the socket in the boot, this socket is live with the key out of the car...

I did however leave the fridge on for nearly two days...ooops and it was dead

 

[dougal74]

Remember, good quality cool boxes are very well insulated & will keep everything cool many hours after they are switched off.
Russ

Can anyone recommend a good quality box as I am interested in getting a decent one?

Many thanks, Adam

 

[flango]

Mines a Thermos had it about 5 years and its done some work, never let me down, off the top of my head think its about 28 litre capacity got it from a specialist camping shop in Sheffield (Towsure) but Blacks Millets etc all stock them.

 

[rf065]

So the socket is permanently live?

Mine only works with the key in

Not the cigarette lighter, I have an accessory socket wired in with its own fuse & 4 separate outlets.

Russ

 

[rf065]

That seems very low - 11.9V is normally considered fully discharged

This one cuts out at 11.6v, mine is a Hella & cuts out at 11.8v, never had a flat battery yet.

MGD Coolers Thermo Electric Cool Boxes & Bag Fridges 12 Volt Cool Box Fridge Free U K Delivery.

Russ

 

[rf065]

Can anyone recommend a good quality box as I am interested in getting a decent one?

Many thanks, Adam

Mine is a Waeco Tropicool Classic, excellent fridge.

Tropicool Thermoelectric Coolbox TC-14

Russ

 

[BTB 500]

This one cuts out at 11.6v, mine is a Hella & cuts out at 11.8v, never had a flat battery yet.

There may well be some voltage drop in the cabling, which is probably what's saving you. 11.6V at the battery would be dead.

A fully charged lead acid battery is 12.7V, sulphation damage starts at 12.4V.

 

[rf065]

There may well be some voltage drop in the cabling, which is probably what's saving you. 11.6V at the battery would be dead.

A fully charged lead acid battery is 12.7V, sulphation damage starts at 12.4V.

When I go into the hidden menu in my CLK, the battery voltage is always shown as less than 12v until the engine is started.

Russ