Quite a number of places sell these items with all the whistles and bells at various prices, but from my own personel experiences I have found that the non-commercial types can be unreliable, especially if they are not kept at peak condition.

Most 'cool-boxes' can be plugged into the vehicle socket during the journey, and with ice packs, they should retain some degree of coolness at the journey end.

Using a standard 'sealed' battery might be a good substitute, as wee eddie as already suggested. If you have an home battery charger, then plug it in on the return home. This method could also act as a replacement for your own vehicle, if needed at a later date.

Soz link mix up LOL

Ring 20AH

It is usual in caravanning to use a leisure battery for this type of use. Slightly different to a car battery and asfer.

Probably the best place to look for the type of charger/battery that you want is a caravan/camping store.

FE thanks very much I was having lots of problems with the Page not fully loading and icons not showing, even with Java Script turned off.

The Link I gave is for Deep Charge Battery's Like caravan battery, they use them on Disabled Scooters, So that they last longer on a Charge. Car Battery's only give out Big amps on Start as that's what car battery's are made for

Car batteries are not suitable for this sort of thing, they are not designed to be used in this sort of way.

You need a leisure battery, these are designed so that they can be run over a long time until they have only a 30% charge left in them with out damage being done to them before they need a recharge.

Car batteries on the other hand are designed to be used with a min 80% charge in them, a car battery will not really be able to manage the deep cycle that a leisure battery will cope with.