Varta A9 Dynamic AGM · Start-Stop battery 50Ah 540A

Yes. The Varta A9 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. It is a AGM battery of 50 Ah, designed for vehicles with 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. Once fitted it is ready to go; registering it via OBD, advisable on most modern models, lets the alternator charge with the optimum profile.

Allow 15-30 minutes and a 10 mm spanner for a L1 case like this one. If the car keeps its battery in the boot or under a seat, it can take up to twice as long. With Start-Stop there are three more points: the negative terminal usually carries a battery sensor (IBS), so undo the cable at the terminal nut without removing the sensor; register the battery via OBD so the alternator applies the correct charging profile; and fit the same technology as the original (AGM or EFB) or higher, because a conventional battery wears out within months. What matters most is the terminal order: removing, negative (−) before positive (+); refitting, positive (+) before negative (−). In between, with the engine off and the key out, release the clamp and fit the new battery the same way round as the original, positive on the right (polarity). For the detail, read our guide to replacing the car battery and, if in doubt, the owner's handbook or a main dealer.

Estimated lifespan of the Varta A9: 5 to 8 years in mild-climate car use with Start-Stop. Treat it as an approximate guide, as every case is different. 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.

Its dimensions are 207×175×190 mm, also written 207x175x190 mm; the height already includes the terminals. In European terms it is a L1 case. Check the room available in your car, because a single millimetre too much can stop the clamp from closing.

The A9 has the positive on the right in a L1 case: that is its polarity. Face the battery with its terminals nearest you and see which side the positive post (+, red ring) is on. A change of polarity from the original means longer cables or a reconfigured system and can cause a short circuit: check it before ordering.

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)). According to our data, 90 verified vehicle versions are compatible with the A9. Always cross-check with what the car manufacturer states in the owner's handbook.

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. A battery interchangeable with the Varta A9 must match it on dimensions (207×175×190 mm), polarity (positive on the right), capacity (50 Ah) and cranking current (540 A).

Same case and same fitting as the A9, from Exide. Compared with the A9 it has 30 A of cold cranking more. It costs 10,30 € less. If you want to save or the A9 is out of stock, it is the safe alternative: same dimensions, same polarity and official warranty.

It is the verified Tudor equivalent for the A9 tray. Compared with the A9 it has 30 A of cold cranking more. It costs 10,30 € less. Decide by price, brand preference and availability: both fit and crank the same.

Capacity of the A9: 50 Ah. 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. Compared with an EFB it resists tilted positions, heavy vibration and extreme temperatures better, and it is the recommended option where there is regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop).

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.