# Auxiliary battery Fulmen FK131 12V 13Ah 200A AGM ![Auxiliary battery Fulmen FK131 12V 13Ah 200A AGM](https://baterias.com/3748-home_default/battery-fulmen-fk131-12v-13ah-200a.jpg) > Fulmen FK131 auxiliary battery 12V 13Ah 200A AGM. Start-Stop Auxiliary range. Dimensions 150×90×145 mm, + terminal on the left. Check fitment by plate. **Category:** [Auxiliary Batteries](https://baterias.com/gb/auxiliary-batteries) → [Fulmen](https://baterias.com/gb/fulmen) - **Canonical URL**: https://baterias.com/gb/battery-fulmen-fk131-12v-13ah-200a - **Language**: en-GB - **Brand**: Fulmen - **Reference**: BCOM-FULMEN-FK131 - **EAN**: 3661024046459 - **MPN**: FK131 - **Last updated**: 2026-10-28 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | FULMEN | | Reference | FK131 | | Model | FULMEN Start-Stop Auxiliary | | Voltage (V) | 12 V | | Largo | 150 mm | | Ancho | 90 mm | | Alto | 145 mm | | Peso | 4.5 kg | | Tecnología | AGM | | EAN | 3661024046459 | | Terminal layout | Positive terminal on the left | | Terminal type | M04 | | Hold down | B00 | | Cold cranking amps (EN) | 200 A | | Capacity (C20) | 13 Ah (c20) | | Case type | C56 | ## Quick description **Fulmen FK131 12V 13Ah 200A** is an auxiliary battery: it supports the Start-Stop system and on-board electronics during stops, without draining the main battery. ## 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 🔌 Voltage 12 V ⚡ Capacity 13 Ah C20 🔋 Cold cranking 200 A EN-1 📏 Dimensions 150×90×145 mm ⚙️ Technology AGM 🧭 Polarity Positive on the left ⚖️ Weight 4,5 kg 🏷️ Model FULMEN Start-Stop Auxiliary ## Description ## Auxiliary battery Fulmen FK131 Start-Stop Auxiliary 13Ah 200A 12V 12*V* Voltage 13*Ah* Capacity 200*A* Cold cranking 4.50*kg* Weight The **12 V**, **13 Ah** **Fulmen FK131** auxiliary battery from the **Start-Stop Auxiliary** range with AGM technology powers the auxiliary network of cars with advanced Start-Stop and heavy electronics. Its 150 × 90 × 145 mm and the positive terminal on the left make it the exact replacement for the 13 Ah battery fitted as standard to many vehicles with an auxiliary battery. - Direct replacement for the original auxiliary battery. - Supports advanced Start-Stop systems. - Protects the main battery and the alternator. - AGM: faster recharging and better cycle resistance than a conventional battery. ### What the Fulmen FK131 is for With 13 Ah, the Fulmen FK131 is the direct replacement for the original auxiliary battery in the auxiliary network of cars with advanced Start-Stop and heavy electronics. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 4.50 kg, M04 terminals and B00 hold-down. ### The Fulmen FK131: Start-Stop Auxiliary range and AGM technology The FK131 is part of the Fulmen **Start-Stop Auxiliary** range. Choosing the right reference within the series comes down to capacity, dimensions and terminals: technology and quality are common to the whole family. AGM (Absorbent Glass Mat) technology seals the electrolyte in glass microfibre. The result is a maintenance-free battery that is highly vibration-resistant and able to withstand deep discharges that would ruin a classic lead-acid battery. ### Dimensions, polarity and mounting It has external dimensions of 150 × 90 × 145 mm and weighs 4.50 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 B00 hold-down and M04 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. ### Fulmen: the maker behind the FK131 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. ### Care and maintenance 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. ### Manufacturer's warranty The Fulmen FK131 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. ### Shipping, delivery and returns Order **before 6:00 pm** with stock available and it leaves today: mainland Spain and Portugal receive it in 24-48 working hours, the islands and the rest of the EU in 3 to 5 days. You have **14 days** to return it if it has not been installed, with free collection on the mainland, and shipment tracking by email. ## Frequently asked questions ### Is the Fulmen FK131 an AGM battery and what are the benefits of AGM? Yes, it is AGM. In an AGM battery such as the FK131, the electrolyte is not free but absorbed in a glass-fibre mat inside a sealed lead-acid battery. Its advantages: more charge/discharge cycles than a conventional battery and better heat tolerance. It is also required in cars with advanced Start-Stop and regenerative braking. ### Is the Fulmen FK131 battery suitable for Start-Stop? AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. The Fulmen FK131 is AGM, so yes, it is designed for Start-Stop cars. It needs nothing to work, though on most modern cars registering it via OBD is advisable so the alternator adjusts its charging profile. As a rule: EFB for basic Start-Stop, AGM when there is also regenerative braking (more cycles); in any case, what the car manufacturer specifies. ### How long does the Fulmen FK131 battery last? As a rough estimate, the Fulmen FK131 typically lasts 5 to 8 years in mild-climate car use with Start-Stop; it is a guide figure, not a guaranteed period. Actual lifespan varies with climate (cold starts, heat evaporating the electrolyte), with usage and short journeys, with the condition of the alternator and charging system, with power draw while parked and with maintenance; the type of car and Start-Stop also count. ### What are the dimensions of the Fulmen FK131 battery? Check the room available in your car, because a single millimetre too much can stop the clamp from closing. Its dimensions are 150×90×145 mm, also written 150x90x145 mm; the height already includes the terminals. ### What polarity does the Fulmen FK131 battery have? Polarity of the Fulmen FK131: positive on the left. It must match your current battery: reversed polarity means lengthening cables or reconfiguring the system, with a risk of short circuit. Seen from the front, terminals towards you, the positive (+) is the post with the red ring. ### Is the FK131 valid for my vehicle? The quickest way is to enter your number plate in the finder: DGT/DVLA/KBA detect model and engine. You can also look at the "Compatible vehicles" tab, verified by our technical team, or send us make, model, engine and year on WhatsApp; we answer during business hours (Mon–Fri 10:00–13:30 and 16:30–18:00 (Spanish time, CET)). Always cross-check with what the car manufacturer states in the owner's handbook. ### What are the equivalents of the FK131 model? Not just any technology will do: an EFB cannot be replaced with a conventional battery in Start-Stop cars. The "Equivalents" section further down lists the recommended alternatives. Interchangeable means the same dimensions, same polarity, same Ah and same CCA; for the FK131, 13 Ah (200 A cranking). ### Fulmen FK131 or Exide EK131: which one to choose? Same case and same fitting as the FK131, from Exide. Compared with the FK131 it has the same Ah and cranking power. It costs €62.20 more. If you want to save or the FK131 is out of stock, it is the safe alternative: same dimensions, same polarity and official warranty. ### Fulmen FK131 or Tudor TK131: which one to choose? The Tudor alternative that fits where the FK131 goes, with the same polarity. Compared with the FK131 it has the same Ah and cranking power. It costs €63.60 more. A straight swap with nothing to adapt; the difference is the price and the brand you prefer. ### What advantages does the Fulmen FK131 AGM battery offer over an EFB? In an AGM (Absorbent Glass Mat) battery the electrolyte is held in a glass-fibre mat: no spills, and many more charge/discharge cycles than a conventional battery. Compared with an EFB it resists tilted positions, heavy vibration and extreme temperatures better, and it is the recommended option where there is regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop). The Fulmen FK131 has a capacity of 13 Ah. ### Do I need to register the Fulmen FK131 on the car after installation? 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 Fulmen FK131, the car will start correctly; the profile adjusts within a few days. ## Equivalent batteries - [EXIDE EK131](https://baterias.com/gb/battery-exide-ek131-12v-12ah-200a) - [TUDOR TK131](https://baterias.com/gb/battery-tudor-tk131-12v-13ah-200a) ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team — automotive battery specialists since 2012. → https://baterias.com/gb/technical-team --- *baterias.com — Automotive batteries · 2026-11-08*