Tudor TK820 AGM Microhybrid · Start-Stop battery 82Ah 800A

Yes, it is AGM. In an AGM battery such as the TK820, the electrolyte is not free but absorbed in a glass-fibre mat inside a sealed lead-acid battery. 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, the AGM technology of the TK820 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. It needs nothing to work, though on most modern cars registering it via OBD is advisable so the alternator adjusts its charging profile.

Our blog guide covers it in detail; if the owner's handbook describes a different procedure, follow the manufacturer. Allow 15-30 minutes and a 10 mm spanner for a L4 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. 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.

There is no exact figure: for a battery such as the Tudor TK820 (AGM), a reasonable guide is 5 to 8 years in mild-climate car use with Start-Stop. 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 Tudor TK820 takes up 315×175×190 mm (length, width and height, terminals included), the European L4 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.

It has the positive on the right (polarity). It must match your current battery: reversed polarity means lengthening cables or reconfiguring the system, with a risk of short circuit. Put it in front of you, terminals towards you: the post with the red ring and the + sign is the positive.

The compatibility list for the TK820 runs to 418 verified vehicle versions. 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 "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 TK820, 82 Ah (800 A cranking).

Same case and same fitting as the TK820, from Varta. Compared with the TK820 it has 2 Ah less. It costs 39,15 € more. If you want to save or the TK820 is out of stock, it is the safe alternative: same dimensions, same polarity and official warranty.

It is the verified Exide equivalent for the TK820 tray. Compared with the TK820 it has the same Ah and cranking power. It costs 2,10 € less. Decide by price, brand preference and availability: both fit and crank the same.

The absorbent glass-fibre mat of an AGM retains the electrolyte, so it cannot leak and withstands considerably more cycles than a conventional battery. 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. The Tudor TK820 has a capacity of 82 Ah.

It is not strictly necessary on most cars, because the alternator detects the change and adapts the charge. The advisable step is to register it via OBD: the charging profile is optimum from the first minute and the battery lasts longer, especially on brands with sophisticated BMS (BMW, Mercedes, Audi, Volvo, Land Rover). Any garage with an OBD scanner can do it in a few minutes. If you prefer to do it yourself: VCDS / Carista (VAG), Bimmercode (BMW) or iCarsoft. Even if you do not register the Tudor TK820, the car will start correctly; the profile adjusts within a few days.