Varta A4 Dynamic AGM · Start-Stop battery 105Ah 950A

Yes, it is AGM. In an AGM battery such as the A4, the electrolyte is not free but absorbed in a glass-fibre mat inside a sealed lead-acid battery. 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.

AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. The Varta A4 is AGM, so yes, it is designed for Start-Stop cars. Once fitted it is ready to go; registering it via OBD, advisable on most modern models, lets the alternator charge with the optimum profile. As a rule: EFB for basic Start-Stop, AGM when there is also regenerative braking (more cycles); in any case, what the car manufacturer specifies.

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. On most cars it is a 15-30 minute job needing only a 10 mm spanner (up to twice as long when the battery is under a seat or in the boot). Steps: 1) switch off and remove the key; 2) find the battery (bonnet, boot or under a seat); 3) undo the negative (−), then the positive (+); 4) remove the clamp and the old battery; 5) fit the new one facing the same way (positive on the right) to match the polarity; 6) connect the positive (+) and finally the negative (−). Our blog guide covers it in detail; if the owner's handbook describes a different procedure, follow the manufacturer.

As a rough estimate, the Varta A4 typically lasts 5 to 8 years in mild-climate car use with Start-Stop; it is a guide figure, not a guaranteed period. 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.

Check the room available in your car, because a single millimetre too much can stop the clamp from closing. Its dimensions are 394×175×190 mm, also written 394x175x190 mm; the height already includes the terminals. In European terms it is a L6 case.

Polarity of the Varta A4: positive on the right. Seen from the front, terminals towards you, the positive (+) is the post with the red ring. 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. The A4 fits 149 verified vehicle versions in our database.

Interchangeable means the same dimensions, same polarity, same Ah and same CCA; for the A4, 105 Ah (950 A cranking). Not just any technology will do: an EFB cannot be replaced with a conventional battery in Start-Stop cars. The "Equivalents" section further down lists the recommended alternatives.

Same range and the same performance as the A4. Compared with the A4 it has the same Ah and cranking power. It costs 54,60 € more. Either one works; decide by price.

The Exide alternative that fits where the A4 goes, with the same polarity. Compared with the A4 it has 1 Ah more. It costs 23,60 € less. A straight swap with nothing to adapt; the difference is the price and the brand you prefer.

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. 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 Varta A4 has a capacity of 105 Ah.

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 there is no starting problem: the alternator adjusts the profile within a few days. To do it yourself: VCDS or Carista on VAG, Bimmercode on BMW, iCarsoft. At a workshop with an OBD scanner it takes minutes.