Exide EK457 · Auxiliary battery 45Ah 380A AGM

Yes. AGM (Absorbent Glass Mat) technology, 45 Ah: sealed lead-acid, with the electrolyte held in glass fibre. It tolerates heat better and handles more cycles than a conventional battery, which is why it is the required technology with advanced Start-Stop and regenerative braking.

Yes: being AGM, the Exide EK457 is designed for Start-Stop cars. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. If the car recovers energy when braking, AGM is recommended for its higher cycle count; for basic Start-Stop, EFB. The manufacturer's specification comes first. It needs nothing to work, though on most modern cars registering it via OBD is advisable so the alternator adjusts its charging profile.

As a guide, you can expect the Exide EK457 to last 5 to 8 years in mild-climate car use with Start-Stop, although the real figure may be higher or lower. Many factors play a part: how it is used (lots of short trips, for example), temperature (cold makes every start harder and intense heat evaporates the electrolyte), the condition of the alternator and charging system, power drawn with the engine off and maintenance, as well as the type of car and whether it has Start-Stop.

The Exide EK457 takes up 237×127×227 mm (length, width and height, terminals included). Before buying, measure the space in your car: one extra millimetre can stop the hold-down clamp from closing.

On the Exide EK457, the polarity is positive on the left. It must match your current battery: reversed polarity means lengthening cables or reconfiguring the system, with a risk of short circuit. To check, stand the battery in front of you with the terminals nearest you: the positive (+) is the one with the red ring.

For your own vehicle: type your number plate into the finder (DGT/DVLA/KBA identify model and engine), check the "Compatible vehicles" tab below, listing vehicles verified by our technical team, or message us on WhatsApp with make, model, engine and year; we reply during business hours (Mon–Fri 10:00–13:30 and 16:30–18:00 (Spanish time, CET)). The car manufacturer's specifications always take priority over our tables. The EK457 typically fits a wide range of European vehicles thanks to its standard DIN case format.

A direct equivalent needs what this EK457 offers: 237×127×227 mm, positive on the left, the same Ah and CCA and AGM technology. See the "Equivalents" section of this page for the recommended options at the same performance level. Mind the technology: in Start-Stop cars an EFB is not swapped for a conventional battery.

Same case and same technology as the EK457: an alternative by size, not an official equivalent. Compared with the EK457 it has the same Ah and cranking power. It costs the same. If the polarity matches and your car had a similar capacity, it works as a replacement; if in doubt, ask us with your model.

Hence it is recommended for advanced Start-Stop with regenerative braking, such as BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO or Volvo i-Stop, and it handles tilting, vibration and extreme temperatures better than an EFB. The absorbent glass-fibre mat of an AGM retains the electrolyte, so it cannot leak and withstands considerably more cycles than a conventional battery. Cold cranking current (EN) of the Exide EK457: 380 A.

On most cars it is not strictly necessary: the alternator detects the new battery and adapts the charge by itself. It is advisable, though, to register it via OBD so the optimum profile applies from the first minute and the battery lasts as long as possible, especially on brands with sophisticated BMS (BMW, Mercedes, Audi, Volvo, Land Rover). Without registration the car starts normally; the alternator simply takes a few days to adjust the profile. To do it yourself: VCDS or Carista on VAG, Bimmercode on BMW, iCarsoft. At a workshop with an OBD scanner it takes minutes.