Contrary to popular belief, the best-known brands are not necessarily the best batteries.
Only the electrical specifications really matter, since all batteries generally come with a three-year warranty.
How to choose the right battery
First of all, the battery has to fit the compartment, so make sure you choose one suited to your car.
Next, pay attention to several figures: the ampere-hours (Ah) and the power that can be delivered on starting (A).
The higher the capacity in A and Ah, the longer the battery will last and the more power it can deliver at any given moment. It is therefore very much in your interest to choose the best-performing ones.
Too powerful, or not powerful enough
it is better to go too powerful than not powerful enough, and there is no risk in doing so. You will simply have more reserve and more power available. The only really important figures are the battery's size (it has to fit) and the 12V rating
Technical specifications of a battery
V for Volt
This is the electrical voltage. Harder to grasp than the ampere, it is broadly the “amount of electricity that can be generated”.
A for Ampere
This is the strength of the current flowing through a cable. The more current (and therefore amperes) there is, the more electrons pass through. The more there are, the more the metal will glow red, because it generates heat: it is the friction of the very numerous electrons compressing against one another. It can be compared to pressure in a garden hose — the harder you turn it up, the more pressure there is.
The figure printed on a car battery shows how many amperes it can deliver for 30 seconds at a temperature of -18°C. The higher that figure, the greater the power delivered over those 30 seconds. So if your car tends to struggle to start, try choosing a high rating for this figure.
Ah for Ampere-hour
This is the capacity it can hold in its “belly”. The higher the figure, the greater your “electricity reserves”. An 800 Ah battery can deliver 800 amperes over one hour… but also 400 amperes for 2 hours, or even 200 for 4 hours.
