Exide EL550 · Start-Stop battery 55Ah 540A EFB

Yes. The EL550 is an EFB (Enhanced Flooded Battery): flooded lead-acid reinforced with plate additives. More affordable than an equivalent AGM and with more cycles than a conventional battery (though fewer than AGM), it is what cars with basic Start-Stop use, without regenerative braking.

Yes. It is a EFB battery of 55 Ah, designed for vehicles with Start-Stop. EFB batteries cover basic Start-Stop (no regenerative braking). 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.

Before you start, check the car handbook: the manufacturer's procedure always comes first. Our full step-by-step guide is on the blog. 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. 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. 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.

Estimated lifespan of the Exide EL550: 4 to 6 years in basic Start-Stop car use. Treat it as an approximate guide, as every case is different. It can vary considerably with usage (short or long journeys), temperature, the condition of the alternator and charging system, power drawn with the engine off and maintenance, plus the car itself and Start-Stop. Cold demands more at every start and intense heat evaporates the electrolyte.

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 EL550 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.

Not sure? Try your number plate in the finder (DGT/DVLA/KBA detect model and engine) or the "Compatible vehicles" tab, checked by our technical team; if your car is not there, send us make, model, engine and year on WhatsApp and we will reply during business hours (Mon–Fri 10:00–13:30 and 16:30–18:00 (Spanish time, CET)). The compatibility list for the EL550 runs to 91 verified vehicle versions. Always cross-check with what the car manufacturer states in the owner's handbook.

To replace the Exide EL550 without modifications, the other battery must be identical in size (L1 case), polarity, Ah and CCA. 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.

The AGM of this size: what cars with Start-Stop and regenerative braking fit from the factory, and a real durability upgrade over the EL550. Compared with the EL550 it has 5 Ah less. It costs 22,80 € more. Essential if your car has Start-Stop, regenerative braking or came with AGM; without those systems it is an upgrade you do not need to pay for.

Same case and same fitting as the EL550, from Tudor. Compared with the EL550 it has the same Ah and cranking power. It costs 19,15 € less. If you want to save or the EL550 is out of stock, it is the safe alternative: same dimensions, same polarity and official warranty.

If your car left the factory with an EFB, that is the right technology and moving to AGM is optional (a marginal improvement); if it had an AGM, an EFB would fall short. It is still flooded lead-acid, but an EFB reinforces the plates with carbon and polyethylene and uses thicker grids. That gives it more cycles than a conventional battery and deeper discharge tolerance, though less than an AGM. It is fitted as standard to cars with basic Start-Stop, without regenerative braking: Renault Energy TCe, Peugeot/Citroën PureTech, Fiat MultiAir, Hyundai/Kia ISG or Ford EcoBoost.

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.