Change your car battery either when there is a defect or when the remaining capacity is no longer sufficient. You can recognise this by various factors:

• Engine starting problems
• Weak lighting

As the battery is heavily unloaded in cold temperatures, a defect is particularly noticeable on winter days. Please note that these starting problems are not exclusively due to the battery. If necessary, contact a garage to check your car.
With normal wear and tear, a battery lasts between four and six years. This value can be greatly reduced by your driving characteristics, such as long periods of standing with the radio and/or lights on or frequent short journeys.

Often, with increased capacity, the price goes up. Conventional lead-acid batteries are much cheaper than EFB variants, which in turn are more affordable than AGM batteries.
Often the cost depends on the car. This is illustrated by the example:

• Opel Corsa C 1.2 75 hp (55 kW) - from approx. £ 45
• Audi A6 Avant (C6) 3.0 240 PS (176 kW) - from approx. £ 50
• BMW 3 (F30) 2.0 136 hp (100 kW) - from approx. £ 141

For small cars with few electrical consumers, small car batteries with comparatively low power and low price are already sufficient. Large cars or modern cars with a lot of electronics not only need more power, but also more expensive battery types due to the automatic start-stop system or brake power regeneration.

For a successful bypass, you first need the appropriate jumper cable and an auxiliary car. This should have a sufficiently charged battery with the same voltage.
The jumper cable usually consists of a black (negative) and a red (positive) cable. You will find all the relevant information about the required procedure in the instruction manual. Pay attention to the following steps so as not to damage the car's electronics unintentionally:

1. Switch off all consumers and motors
2. Connect the red cable to the positive terminals of both batteries. First to the donor car, then to the discharged battery.
3. Connect the black cable to the negative terminal of the intact battery.
4. Find a ground point with the other end of the black cable, for example the engine block.
5. Now start the engine of the intact battery and then the car with the discharged battery.

After bypassing, it is important that you remove the cables in reverse order and then charge the battery by driving for a while. If the bypass did not work, either the battery is defective, the cable is not of sufficient diameter or the donor battery is not sufficiently charged.

Both the acid battery and the gel battery are used as vehicle batteries. However, both batteries have different advantages, which we have summarized for you in the following table:

Because of its advantages, the gel battery is often used, especially by motorcyclists or campers.

New batteries have a nine-digit number, also called ETN (European Type Number). Among other things, this provides you with information about the cold start current, nominal voltage and the design. If the ETN number of two batteries is the same, you can change them without hesitation.
The numbers are coded as follows:

Here is an example:

• Varta Blue Dynamic 540 125 033
• Rated voltage (5): 12 Volt
• Capacity in ampere hours (40): 40 Ah
• DIN data (125): Battery was newly registered, 25 contains data on forms
• Cold test current in amperes (033): 330 A

Old batteries are hazardous waste, which you should take to a recycling centre or workshop if possible. This is highly recommended as batteries are toxic and can harm the environment if disposed of incorrectly.
When transporting the old battery, make sure it is placed on a suitable surface, i.e. a boot liner, so that it does not fall over.