Fulmen FK151 Start-Stop Auxiliary · Battery 15Ah 200A AGM

Yes: the FK151 from Fulmen uses AGM (Absorbent Glass Mat) technology, a sealed lead-acid battery whose electrolyte soaks a glass-fibre mat. 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, the AGM technology of the FK151 is built for Start-Stop. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. Basic Start-Stop: EFB. Start-Stop with regenerative braking: AGM, which withstands more cycles. Check the handbook for the technology the car manufacturer requires. Once fitted it is ready to go; registering it via OBD, advisable on most modern models, lets the alternator charge with the optimum profile.

There is no exact figure: for a battery such as the Fulmen FK151 (AGM), a reasonable guide is 5 to 8 years in mild-climate car use with Start-Stop. 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.

Its dimensions are 150×90×145 mm, also written 150x90x145 mm; the height already includes the terminals. Check the room available in your car, because a single millimetre too much can stop the clamp from closing.

It has the positive on the left (polarity). Put it in front of you, terminals towards you: the post with the red ring and the + sign is the positive. A change of polarity from the original means longer cables or a reconfigured system and can cause a short circuit: check it before ordering.

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)). Always cross-check with what the car manufacturer states in the owner's handbook.

Interchangeable means the same dimensions, same polarity, same Ah and same CCA; for the FK151, 15 Ah (200 A cranking). 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.

It is the verified Exide equivalent for the FK151 tray. Compared with the FK151 it has the same Ah and cranking power. It costs €54.60 more. Decide by price, brand preference and availability: both fit and crank the same.

The Tudor alternative that fits where the FK151 goes, with the same polarity. Compared with the FK151 it has the same Ah and cranking power. It costs €64.95 more. A straight swap with nothing to adapt; the difference is the price and the brand you prefer.

For regenerative braking systems such as BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO or Volvo i-Stop, AGM is the recommendation; it also copes better than an EFB with tilting, vibration and extreme temperatures. In an AGM (Absorbent Glass Mat) battery the electrolyte is held in a glass-fibre mat: no spills, and many more charge/discharge cycles than a conventional battery. The Fulmen FK151 has a capacity of 15 Ah.

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. Any workshop with an OBD scanner does it in a few minutes; DIY, with VCDS or Carista (VAG group), Bimmercode (BMW) or iCarsoft. Even if you do not register the Fulmen FK151, the car will start correctly; the profile adjusts within a few days.