# Fulmen FK820 · Start-Stop battery 12V 82Ah 800A ![Fulmen FK820 · Start-Stop battery 12V 82Ah 800A](https://bateriasonline.es/2660-home_default/fulmen-fk820.jpg) > Fulmen FK820: 82 Ah Start-Stop battery, 800 A (EN), 315×175×190 mm, positive terminal on the right, L4 case, AGM. Equivalent to Exide EK820 and Tudor TK820. **Category:** [Start-Stop batteries (AGM and EFB)](https://bateriasonline.es/en/start-stop-batteries-agm-efb) → [Fulmen](https://bateriasonline.es/en/fulmen-batteries) - **Canonical URL**: https://bateriasonline.es/en/fulmen-fk820 - **Language**: en - **Brand**: Fulmen - **Reference**: BOL-FULMEN-FK820 - **EAN**: 3661024047418 - **MPN**: FK820 - **Last updated**: 2026-11-06 ## Technical specifications | Feature | Value | |---|---| | Brand | Fulmen | | Range | FULMEN AGM | | Application | Start-Stop cars | | Technology | AGM | | Voltage | 12 V | | Capacity | 82 Ah | | Cold cranking amps (EN) | 800 A | | Length | 315 mm | | Width | 175 mm | | Height | 190 mm | | Weight | 23.3 kg | | Polarity | Positive terminal on the right | | Case size | L4 (315 × 175 × 190 mm) | ## Quick description The Fulmen FK820 is a Start-Stop battery (AGM) with 12 V, 82 Ah and 800 A cold cranking current, case size L4 (315 × 175 × 190 mm), with the positive terminal on the right. ## Description ## Who the Fulmen FK820 is for The Fulmen FK820 is a battery for cars with Start-Stop: it withstands many more starting and partial-discharge cycles than a conventional battery and powers the electronics every time the engine stops at the lights. It takes repeated discharges without losing capacity the way a conventional battery would. At 82 Ah it moves into large diesels, SUVs, vans and cars with heavy electrical equipment. The FK820 belongs to the Fulmen FULMEN AGM range. [More Fulmen batteries](https://bateriasonline.es/en/fulmen-batteries) ## Fulmen FK820 vs FK800 and FK720: differences How the FK820 compares with Fulmen batteries of similar size and capacity: | Model | Capacity | Cold cranking (EN) | Dimensions (mm) | Positive | Weight | |---|---|---|---|---|---| | Fulmen FK820 (this one) | 82 Ah | 800 A | 315 × 175 × 190 | right | 23.3 kg | | Fulmen FK800 | 80 Ah | 800 A | 315 × 175 × 190 | right | 23.1 kg | | Fulmen FK720 | 72 Ah | 760 A | 278 × 175 × 190 | right | 20.6 kg | - Fulmen FK800: 2 Ah less, the same cranking power, the same L4 case. - Fulmen FK720: 10 Ah less, 40 A less cranking power, a different case (278 × 175 × 190 mm). ## Fulmen FK820 codes and part numbers Look for any of these FK820 codes on your current battery or in the manufacturer's catalogue: | Commercial reference | FK820 | |---|---| | EAN | 3661024047418 | | Case size (EN) | L4 | | Not to be confused with | Fulmen FK620 (62 Ah, 680 A), Fulmen FK720 (72 Ah, 760 A), Fulmen FK800 (80 Ah, 800 A) | ## Equivalents and alternatives to the Fulmen FK820 As the FK820 is an AGM battery, we only list other AGM batteries with its dimensions and polarity: neither an EFB nor a conventional battery can replace it. | Model | Technology | Capacity | Cold cranking (EN) | Dimensions (mm) | |---|---|---|---|---| | Exide EK820 | AGM | 82 Ah | 800 A | 315 × 175 × 190 | | Tudor TK820 | AGM | 82 Ah | 800 A | 315 × 175 × 190 | | Deta DK820 | AGM | 82 Ah | 800 A | 315 × 175 × 190 | | Varta A6 | AGM | 80 Ah | 800 A | 315 × 175 × 190 | | Deta DK800 | AGM | 80 Ah | 800 A | 315 × 175 × 190 | | Fulmen FK800 | AGM | 80 Ah | 800 A | 315 × 175 × 190 | Its Bosch equivalent is the Bosch S5 A11, the same as for the Varta A6. Bosch is not part of our catalogue; we list it so you can compare. ## What to look at before buying the FK820 - The FK820 needs 315 × 175 × 190 mm of space (European case size L4): measure it with the hold-down clamp in place. - The FK820 has the positive terminal on the right: compare it with your current battery. - With 82 Ah, the FK820 replaces an original battery of that capacity or slightly less. - Check the EN amps on your battery: if it says 800 A or less, the FK820 covers your engine. - The FK820 is AGM: it replaces an AGM or an EFB of the same size. You can swap an EFB for an AGM, but not an AGM for an EFB. ## Inside the FK820: AGM technology The FK820 is AGM: the electrolyte is absorbed in glass fibre mats, so it is sealed and spill-proof. Being sealed, the FK820 can be fitted in the boot or under a seat with no risk of spills. ## Frequently asked questions about the Fulmen FK820 ### Fulmen FK820 or FK800? Compared with the FK820, the Fulmen FK800 has 2 Ah less. With the same cranking power (800 A), the FK820 and the FK800 differ in capacity: the one with more Ah supports more load with the engine off. Both measure 315 × 175 × 190 mm, so they fit the same tray. ### Can the Fulmen FK820 be used in a car with Start-Stop? Yes. As an AGM battery, the FK820 handles automatic engine stop and brake energy recovery, and it can replace an EFB of the same size. ### How much does the Fulmen FK820 weigh? The FK820 weighs 23.3 kg. For reference, the Fulmen FK800 (80 Ah) weighs 23.1 kg. ### Which battery is equivalent to the Fulmen FK820? Only other AGM batteries with its dimensions and polarity: Exide EK820, Tudor TK820 and Deta DK820. Neither an EFB nor a conventional battery replaces the FK820. Its Bosch equivalent is the Bosch S5 A11, the same as for the Varta A6. Bosch is not part of our catalogue; we list it so you can compare. ### What case size is the Fulmen FK820? Case size L4: 315 × 175 × 190 mm. The FK820 fits any standard L4 battery tray such as the Exide EK820. ### Which side is the positive terminal on the Fulmen FK820? The FK820 has the positive terminal on the right, looking at the battery from its long side with the terminals closest to you. ## More batteries to compare with the FK820 - [More start-Stop batteries (AGM and EFB)](https://bateriasonline.es/en/start-stop-batteries-agm-efb) - [The whole Fulmen range](https://bateriasonline.es/en/fulmen-batteries) - [Exide EK820](https://bateriasonline.es/en/exide-ek820) · 82 Ah, 800 A, 315×175×190 mm - [Tudor TK820](https://bateriasonline.es/en/tudor-tk820) · 82 Ah, 800 A, 315×175×190 mm --- *bateriasonline.es — Batteries and accessories · 2026-11-11*