# Auxiliary battery Fulmen FK143 12V 14Ah 80A AGM ![Auxiliary battery Fulmen FK143 12V 14Ah 80A AGM](https://baterias.com/3749-home_default/battery-fulmen-fk143-12v-14ah-80a.jpg) > Fulmen FK143 auxiliary battery 12V 14Ah 80A AGM. Start-Stop Auxiliary range. Dimensions 150Γ—100Γ—100 mm, + terminal on the left. Check fitment by plate. **Category:** [Auxiliary Batteries](https://baterias.com/gb/auxiliary-batteries) β†’ [Fulmen](https://baterias.com/gb/fulmen) - **Canonical URL**: https://baterias.com/gb/battery-fulmen-fk143-12v-14ah-80a - **Language**: en-GB - **Brand**: Fulmen - **Reference**: BCOM-FULMEN-FK143 - **EAN**: 3661024046466 - **MPN**: FK143 - **Last updated**: 2026-10-28 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | FULMEN | | Reference | FK143 | | Model | FULMEN Start-Stop Auxiliary | | Voltage (V) | 12 V | | Largo | 150 mm | | Ancho | 100 mm | | Alto | 100 mm | | Peso | 4.2 kg | | TecnologΓ­a | AGM | | EAN | 3661024046466 | | Terminal layout | Positive terminal on the left | | Terminal type | Screwed/Lug | | Hold down | B0 | | Cold cranking amps (EN) | 80 A | | Capacity (C20) | 14 Ah (c20) | | Case type | C76 | ## Quick description **Fulmen FK143 12V 14Ah 80A** is an AGM support battery designed for daily cycling while keeping voltage stable for the vehicle systems. ## Why this auxiliary battery? - **Designed for Start-Stop** built for the intensive cycling of modern cars - **2 to 3 times longer life** vs fitting a cheap conventional battery - **Fast recovery** recharges in minutes once the engine is running πŸ”Œ Voltage 12 V ⚑ Capacity 14 Ah C20 πŸ”‹ Cold cranking 80 A EN-1 πŸ“ Dimensions 150Γ—100Γ—100 mm βš™οΈ Technology AGM 🧭 Polarity Positive on the left βš–οΈ Weight 4,2 kg 🏷️ Model FULMEN Start-Stop Auxiliary ## Description ## Auxiliary battery Fulmen FK143 Start-Stop Auxiliary 14Ah 80A 12V 12*V* Voltage 14*Ah* Capacity 80*A* Cold cranking 4.20*kg* Weight Designed for the auxiliary network of cars with advanced Start-Stop and heavy electronics, the **Fulmen FK143** from the **Start-Stop Auxiliary** range stabilises the voltage with **14 Ah** with AGM technology. It replaces the original battery without adaptation in vehicles with an auxiliary battery with a 150 Γ— 100 Γ— 100 mm format: same 14 Ah capacity and the positive terminal on the left. - AGM technology: absorbed electrolyte, no spills, can be mounted at an angle. - Stabilises the onboard network voltage. - Sealed AGM: safe when installed in the cabin. - Maintenance-free. ### Size, terminals and hold-down of the Fulmen FK143 It has external dimensions of 150 Γ— 100 Γ— 100 mm and weighs 4.20 kg. The positive terminal on the left decides which side the cables end up on: it is the detail that causes most buying mistakes, so check it before ordering. It uses a B0 hold-down and Screwed/Lug terminals, the system that anchors and connects it in the vehicle. Before replacing it, measure your current battery tray: if all three dimensions and the terminal positions match, the swap is direct and needs no adapters. ### What the Fulmen FK143 is for The Fulmen FK143 is designed for the auxiliary network of cars with advanced Start-Stop and heavy electronics: it stabilises the voltage and protects the main battery in cars with heavy electronics. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 4.20 kg, Screwed/Lug terminals and B0 hold-down. ### The Fulmen FK143: Start-Stop Auxiliary range and AGM technology Within the Fulmen catalogue, the **Start-Stop Auxiliary** series groups the references designed for this use. The FK143 is the 14 Ah model of that family, with the same performance as its siblings in other sizes. In an AGM battery the electrolyte is absorbed in glass-fibre separators: there is no free liquid, it cannot spill and it can be mounted at an angle. That construction lowers internal resistance, speeds up recharging and multiplies cycle life compared with a conventional battery. ### What Fulmen does differently With more than a century of history, Fulmen offers complete ranges for cars, trucks, motorcycles and leisure with the industrial quality of the Exide group. At baterias.com we work directly with the manufacturer or its official distributor: real stock, brand-new product and official warranty. ### Official warranty The Fulmen FK143 comes with the **manufacturer's official warranty** against manufacturing defects. If it fails through a defect within the warranty period, we replace it at no cost to you. ### How to make it last longer The auxiliary battery works alongside the main one: if a support-network fault warning appears, check both. Replace it with the same technology and capacity as the original. ### Shipping, delivery and returns Same-day dispatch from our warehouse for in-stock orders placed **before 6:00 pm**: 24-48 working hours in mainland Spain and Portugal, 3 to 5 days in the islands and the rest of Europe. Returns are accepted for **14 days** if the battery has not been used (free collection on the Iberian mainland). You will receive tracking by email. ## Frequently asked questions ### Is this battery AGM? What is it for? Yes. The FK143 from Fulmen uses AGM (Absorbent Glass Mat) technology: a sealed lead-acid battery where the electrolyte is absorbed in a glass-fibre mat. It withstands more charge/discharge cycles than a conventional one, handles heat better and is the required technology for cars with advanced Start-Stop and regenerative braking. Expected lifespan: 5-8 years under normal conditions. ### Is the Fulmen FK143 battery suitable for Start-Stop? Yes. As AGM technology it is designed for Start-Stop vehicles. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. EFB is recommended for basic Start-Stop; AGM is recommended when regenerative braking is also present, thanks to its higher cycle capability. It works straight out of the box β€” on most modern vehicles registering the battery via OBD is recommended so the alternator automatically applies the optimal charging profile. ### How long does the Fulmen FK143 battery last? Expected lifespan of the Fulmen FK143 is 5 to 8 years in mild-climate car use with Start-Stop. In cold regions it drops slightly due to cold-start stress; in very hot regions it also drops because of electrolyte evaporation. To extend its life: avoid deep discharges (headlights on with engine off), have the alternator checked yearly, and keep the battery clean and properly secured. ### What are the dimensions of the Fulmen FK143 battery? Dimensions (length Γ— width Γ— height) are 150Γ—100Γ—100 mm β€” also written as 150x100x100 mm β€” following the European DIN standard. Always measure the space in your car before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals. ### Which side is the positive terminal on this battery? Polarity: positive on the left. To identify it, place the battery in front of you with the terminals facing you and check which side the positive (+, marked with a red ring) is on. Before buying, verify the polarity matches your current battery: switching polarity forces longer cables or system reconfiguration, with short-circuit risk. ### Will the Fulmen FK143 battery fit my car? Three options to confirm: 1) enter your number plate in the finder (DGT/DVLA/KBA auto-detect your model and engine); 2) check the "Compatible vehicles" tab on this page, where we list every vehicle verified by our technical team; 3) if you cannot find your model, message us on WhatsApp with brand, model, engine and year β€” we reply during business hours (Mon–Fri 10:00–13:30 and 16:30–18:00 (Spanish time, CET)). The FK143 typically fits a wide range of European vehicles thanks to its standard DIN case format. ### Which batteries are equivalent to the Fulmen FK143? Directly interchangeable batteries (same dimensions, same polarity, same Ah and CCA) are the OEM equivalents from leading brands: Bosch, Tudor, Exide and, depending on the model, Banner or Yuasa. Exact equivalence depends on technology β€” an EFB cannot be replaced with a conventional battery in Start-Stop cars. See the "Equivalents" section to view recommended options at the same performance level. ### What advantages does the Fulmen FK143 AGM battery offer over an EFB? AGM (Absorbent Glass Mat) technology uses absorbent fibreglass that retains the electrolyte, eliminating leaks and allowing up to 3Γ— more charge/discharge cycles than a conventional battery. It is the recommended option when the car has advanced Start-Stop with regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop). Withstands tilted positions, high vibration and extreme temperatures better than EFB. The Fulmen FK143 is fully original and meets European EN 50342-6 standards for advanced Start-Stop. ### Do I need to register the Fulmen FK143 on the car after installation? On most cars it is not strictly necessary β€” the alternator detects the new battery and adapts the charge automatically. It is recommended to register the battery via OBD so that the alternator applies the optimal charging profile from the first minute and extends the battery life as much as possible (especially on brands with sophisticated BMS: BMW, Mercedes, Audi, Volvo, Land Rover). Any workshop with an OBD scanner (~10-15 € labour) does it in 5 minutes. DIY apps: VCDS / Carista (VAG), Bimmercode (BMW), iCarsoft. If you do not register, the car will still start correctly β€” the alternator just takes a few days to adjust the profile. The Fulmen FK143 ships factory-charged at 80-90% so you can use it straight after fitting. ## Equivalent batteries - [TUDOR TK143](https://baterias.com/gb/battery-tudor-tk143-12v-14ah-80a) - [EXIDE EK143](https://baterias.com/gb/battery-exide-ek143-12v-14ah-80a) ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team β€” automotive battery specialists since 2012. β†’ https://baterias.com/gb/technical-team --- *baterias.com β€” Automotive batteries Β· 2026-11-04*