# Auxiliary battery Fulmen FK111 12V 11Ah 150A AGM ![Auxiliary battery Fulmen FK111 12V 11Ah 150A AGM](https://baterias.com/3747-home_default/battery-fulmen-fk111-12v-11ah-150a.jpg) > Fulmen FK111 auxiliary battery 12V 11Ah 150A AGM. Start-Stop Auxiliary range. Dimensions 150×90×130 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-fk111-12v-11ah-150a - **Language**: en-GB - **Brand**: Fulmen - **Reference**: BCOM-FULMEN-FK111 - **EAN**: 3661024046343 - **MPN**: FK111 - **Last updated**: 2026-10-28 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | FULMEN | | Reference | FK111 | | Model | FULMEN Start-Stop Auxiliary | | Voltage (V) | 12 V | | Largo | 150 mm | | Ancho | 90 mm | | Alto | 130 mm | | Peso | 3.9 kg | | Tecnología | AGM | | EAN | 3661024046343 | | Terminal layout | Positive terminal on the left | | Terminal type | M04 | | Hold down | B00 | | Cold cranking amps (EN) | 150 A | | Capacity (C20) | 11 Ah (c20) | | Case type | C55 | ## Quick description **Fulmen FK111 12V 11Ah 150A** 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 11 Ah C20 🔋 Cold cranking 150 A EN-1 📏 Dimensions 150×90×130 mm ⚙️ Technology AGM 🧭 Polarity Positive on the left ⚖️ Weight 3,9 kg 🏷️ Model FULMEN Start-Stop Auxiliary ## Description ## Auxiliary battery Fulmen FK111 Start-Stop Auxiliary 11Ah 150A 12V 12*V* Voltage 11*Ah* Capacity 150*A* Cold cranking 3.90*kg* Weight The **Fulmen FK111** with AGM technology is the **11 Ah**, **12 V** support battery for the auxiliary network of cars with advanced Start-Stop and heavy electronics. It replaces the original battery without adaptation in vehicles with an auxiliary battery with a 150 × 90 × 130 mm format: same 11 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. ### Will it fit your current battery tray? In terms of format, the Fulmen FK111 measures 150 × 90 × 130 mm (length × width × height) and weighs 3.90 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. Checking the three dimensions and the terminal position before buying avoids the most common mistake when replacing a battery. ### What the Fulmen FK111 is for With 11 Ah, the Fulmen FK111 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 3.90 kg, M04 terminals and B00 hold-down. ### The Fulmen FK111: Start-Stop Auxiliary range and AGM technology Within the Fulmen catalogue, the **Start-Stop Auxiliary** series groups the references designed for this use. The FK111 is the 11 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. ### Fulmen: the maker behind the FK111 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. All the Fulmen batteries in our catalogue are genuine product, recently manufactured and covered by the manufacturer's warranty. ### Warranty and coverage The Fulmen FK111 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. ### Care and maintenance Charge with a charger that has an AGM mode: it limits the voltage and protects the glass-fibre separators. The auxiliary battery works alongside the main one: if a support-network fault warning appears, check both. ### When you get it and how to return it Orders placed **before 6:00 pm** with the battery in stock ship the same day. Delivery in mainland Spain and Portugal takes 24-48 working hours; for the Balearic Islands and the rest of the European Union allow 3 to 5 working days. You have **14 days** to return an unused battery; in mainland Spain and Portugal collection is free. We email you the tracking number as soon as the parcel ships. ## Frequently asked questions ### Is the Fulmen FK111 an AGM battery and what are the benefits of AGM? Yes, it is AGM. In an AGM battery such as the FK111, the electrolyte is not free but absorbed in a glass-fibre mat inside a sealed lead-acid battery. It is the technology required by cars with advanced Start-Stop and regenerative braking. It withstands more cycles than a conventional battery and copes better with heat. ### Is the FK111 model suitable for Start-Stop cars? Yes. It is a AGM battery of 11 Ah, designed for vehicles with Start-Stop. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. It works once fitted; on most modern cars, registering it via OBD is advisable so the alternator applies the optimum 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 FK111 battery last? Estimated lifespan of the Fulmen FK111: 5 to 8 years in mild-climate car use with Start-Stop. 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. ### What are the measurements of the FK111 model? Measure the battery tray before ordering: a one-millimetre difference is enough for the hold-down clamp not to close. It measures 150×90×130 mm in length × width × height, with the terminals included in the height. ### What polarity does the Fulmen FK111 battery have? The FK111 has the positive on the left: that is its polarity. Face the battery with its terminals nearest you and see which side the positive post (+, red ring) is on. Compare it with the battery you are replacing: if it does not match, cables must be lengthened or the system reconfigured, with a risk of short circuit. ### Is the FK111 valid for my vehicle? 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)). In every case, the car manufacturer's specifications (owner's handbook) take precedence. ### Which batteries are equivalent to the Fulmen FK111? Interchangeable means the same dimensions, same polarity, same Ah and same CCA; for the FK111, 11 Ah (150 A cranking). 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. ### Fulmen FK111 or Exide EK111: which one to choose? The Exide alternative that fits where the FK111 goes, with the same polarity. Compared with the FK111 it has the same Ah and cranking power. It costs €33.60 more. A straight swap with nothing to adapt; the difference is the price and the brand you prefer. ### Fulmen FK111 or Tudor TK111: which one to choose? It is the verified Tudor equivalent for the FK111 tray. Compared with the FK111 it has the same Ah and cranking power. It costs €169.70 more. Decide by price, brand preference and availability: both fit and crank the same. ### When do I need an AGM battery like this one? It is the recommended choice for advanced Start-Stop with regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop) and copes better than an EFB with tilting, vibration and extreme temperatures. AGM means Absorbent Glass Mat: the electrolyte soaks a glass-fibre mat (no spills), and an AGM battery lasts many more cycles than a conventional one. The Fulmen FK111 has a capacity of 11 Ah. ### Is there anything to do after replacing a Start-Stop battery? 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 Fulmen FK111, the car will start correctly; the profile adjusts within a few days. ## Equivalent batteries - [TUDOR TK111](https://baterias.com/gb/battery-tudor-tk111-11ah-150a) - [EXIDE EK111](https://baterias.com/gb/battery-exide-ek111-12v-11ah-150a) ## 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*