Varta E46 Dynamic EFB · Start-Stop battery 75Ah 730A

Yes: the E46 (75 Ah) is an EFB, an evolution of the flooded lead-acid battery with additives that strengthen the plates. For cycles it sits between a conventional battery and an AGM, and it costs less than an equivalent AGM; it is the technology for cars with basic Start-Stop, without regenerative braking.

EFB batteries cover basic Start-Stop (no regenerative braking). The Varta E46 is EFB, so yes, it is designed for Start-Stop cars. Basic Start-Stop: EFB. Start-Stop with regenerative braking: AGM, which withstands more cycles. Check the handbook for the technology the car manufacturer requires. It works once fitted; on most modern cars, registering it via OBD is advisable so the alternator applies the optimum charging profile.

Our blog guide covers it in detail; if the owner's handbook describes a different procedure, follow the manufacturer. Tool: a 10 mm spanner. Time: 15-30 minutes on almost every car, and up to double if the battery is not under the bonnet but in the boot or under a seat. The right order: engine off and key out; disconnect the negative (−) first, then the positive (+); release the hold-down clamp, lift out the old battery and seat the new one in the same position (positive on the right), keeping the polarity; reconnect the positive (+) first and the negative (−) last. Start-Stop or BMS specifics: do not remove the IBS sensor on the negative terminal (just loosen the cable nut); after the swap, register the battery via OBD so the alternator charges with the right profile; and never step down in technology: if the car had AGM or EFB, the new one must be the same or better, as a conventional battery lasts only a few months.

As a rough estimate, the Varta E46 typically lasts 4 to 6 years in basic Start-Stop car use; it is a guide figure, not a guaranteed period. 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 Varta E46 takes up 315×175×175 mm (length, width and height, terminals included), the European LB4 case size, with a B13 hold-down. Before buying, measure the space in your car: one extra millimetre can stop the hold-down clamp from closing.

Polarity of the Varta E46: positive on the right. Seen from the front, terminals towards you, the positive (+) is the post with the red ring. Compare it with the battery you are replacing: if it does not match, cables must be lengthened or the system reconfigured, with a risk of short circuit.

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 compatibility list for the E46 runs to 67 verified vehicle versions.

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. Interchangeable means the same dimensions, same polarity, same Ah and same CCA; for the E46, 75 Ah (730 A cranking).

Same case and same fitting as the E46, from Tudor. Compared with the E46 it has the same Ah and cranking power. It costs 38,00 € less. If you want to save or the E46 is out of stock, it is the safe alternative: same dimensions, same polarity and official warranty.

Same case and same fitting as the E46, from Exide. Compared with the E46 it has the same Ah and cranking power. It costs 5,00 € more. If you want to save or the E46 is out of stock, it is the safe alternative: same dimensions, same polarity and official warranty.

The EFB (Enhanced Flooded Battery) is a reinforced flooded battery: plates with carbon and polyethylene additives and thicker grids, giving it more cycles than a conventional one; for cycles and deep discharges it still sits below an AGM. Many basic Start-Stop systems (no regenerative braking) come with it from the factory, such as Renault Energy TCe, Peugeot/Citroën PureTech, Fiat MultiAir, Hyundai/Kia ISG and Ford EcoBoost. Rule of thumb: car with an EFB from new, EFB (AGM is an optional, marginal upgrade); car with an AGM from new, AGM.

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 Varta E46, the car will start correctly; the profile adjusts within a few days.