All battery chargers for cars follow the same basic design principle - a portable unit that allows the user to recharge a car battery, either because it's depleted or as a means of keeping an eye on the battery's health. They're relatively compact - like a 12 v air compressor or smaller in some cases - and they're generally inexpensive.
Whether or not a battery discharges its power or simply because batteries need maintaining in general - it's a good idea to make sure you've got a good quality battery charger to hand. There's plenty of choice on the market and you don't have to blow a huge whole in the budget in order to buy one.
The five best automotive battery chargers are featured below. They're all great value for money, designed according to need and manufactured to a high standard.