Tudor TK457 · Auxiliary battery 45Ah 380A AGM

Yes. The Tudor TK457 is AGM (Absorbent Glass Mat): sealed lead-acid, with the electrolyte absorbed in glass fibre. Compared with a conventional battery it withstands more charge/discharge cycles and handles heat better; it is the required technology for cars with advanced Start-Stop and regenerative braking.

Yes, the AGM technology of the TK457 is built for Start-Stop. 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.

There is no exact figure: for a battery such as the Tudor TK457 (AGM), a reasonable guide is 5 to 8 years in mild-climate car use with Start-Stop. What weighs most: temperature (cold makes starts harder and intense heat evaporates the electrolyte), frequent short trips, the condition of the alternator and charging system, power draw while parked and maintenance, not forgetting the type of car and Start-Stop.

The Tudor TK457 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.

It has the positive on the left (polarity). It must match your current battery: reversed polarity means lengthening cables or reconfiguring the system, with a risk of short circuit. Put it in front of you, terminals towards you: the post with the red ring and the + sign is the positive.

Three routes: the "Compatible vehicles" tab on this page, with the vehicles verified by our technical team; your number plate in the finder, from which DGT/DVLA/KBA detect model and engine; and WhatsApp, with make, model, engine and year, 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 "Equivalents" section of this page gathers the recommended options with equivalent performance; remember that in Start-Stop cars an EFB should not be replaced with a conventional battery. A direct equivalent needs what this TK457 offers: 237×127×227 mm, positive on the left, the same Ah and CCA and AGM technology.

Same case and same technology as the TK457: an alternative by size, not an official equivalent. Compared with the TK457 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.

The absorbent glass-fibre mat of an AGM retains the electrolyte, so it cannot leak and withstands considerably more cycles than a conventional battery. It is the recommended choice for advanced Start-Stop with regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop) and copes better than an EFB with tilting, vibration and extreme temperatures. Cold cranking current (EN) of the Tudor TK457: 380 A.

The alternator detects the new battery and adapts the charge automatically, so on most cars it is not compulsory. Even so, it is advisable to register it via OBD so charging is optimum from the first minute and the battery lasts longer, particularly on BMW, Mercedes, Audi, Volvo or Land Rover, with more sophisticated BMS. Without registration the car starts normally; the alternator simply takes a few days to adjust the profile. Any workshop with an OBD scanner does it in a few minutes; DIY, with VCDS or Carista (VAG group), Bimmercode (BMW) or iCarsoft.