# Auxiliary battery Fulbat AUX12 12V 10.5Ah AGM ![Auxiliary battery Fulbat AUX12 12V 10.5Ah AGM](https://baterias.com/6486-home_default/battery-fulbat-aux12-12v-10-5ah.jpg) > Fulbat AUX12 auxiliary battery 12V 10.5Ah AGM. Auxiliary AGM range. Dimensions 150Γ—87Γ—130 mm, + terminal on the left. Check fitment by plate. **Category:** [Auxiliary Batteries](https://baterias.com/gb/auxiliary-batteries) β†’ [FULBAT](https://baterias.com/gb/fulbat) - **Canonical URL**: https://baterias.com/gb/battery-fulbat-aux12-12v-10-5ah - **Language**: en-GB - **Brand**: FULBAT - **Reference**: BCOM-FULBAT-AUX12 - **MPN**: AUX12 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | FULBAT | | Model | FULBAT Auxiliary AGM | | Voltage (V) | 12 V | | Largo | 150 mm | | Ancho | 87 mm | | Alto | 130 mm | | TecnologΓ­a | AGM | | Terminal layout | Positive left | | Capacity (C20) | 10.5 Ah | | Capacity (C10) | 10 Ah (c10) | ## Quick description **Fulbat AUX12 12V 10Ah** 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 10 Ah C20 πŸ“ Dimensions 150Γ—87Γ—130 mm βš™οΈ Technology AGM 🧭 Polarity Positive on the left 🏷️ Model FULBAT Auxiliary AGM ## Description ## Auxiliary battery Fulbat AUX12 10.5Ah 12V 12*V* Voltage 10.5*Ah* Capacity The **Fulbat AUX12** with AGM technology is the **10.5 Ah**, **12 V** support battery for the auxiliary network of cars with advanced Start-Stop and heavy electronics. Measuring 150 Γ— 87 Γ— 130 mm and the positive terminal on the left, it is the direct replacement for vehicles with an auxiliary battery fitted from the factory with a 10.5 Ah battery of this format. - Supports advanced Start-Stop systems. - Direct replacement for the original auxiliary battery. - AGM: faster recharging and better cycle resistance than a conventional battery. - Protects the main battery and the alternator. ### What the Fulbat AUX12 is for The Fulbat AUX12 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. ### Will it fit your current battery tray? It has external dimensions of 150 Γ— 87 Γ— 130 mm. 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. For a direct replacement, the current battery tray must accept these dimensions and the same terminal layout; otherwise adapters will be needed or the hold-down will change. ### What Fulbat does differently French brand Fulbat is a European reference in motorcycle, garden and leisure batteries: compact ranges, clear JIS codes and a consistent quality that workshops know well. At baterias.com we work directly with the manufacturer or its official distributor: real stock, brand-new product and official warranty. ### Technology inside the Fulbat AUX12 Within the Fulbat catalogue, the AUX12 is the 10.5 Ah model designed for this application. 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. ### 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. ### Warranty and coverage The Fulbat AUX12 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 Same-day dispatch from our warehouse for in-stock orders placed **before [[ks:cutoff]]**: 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 **[[ks:return_days]] days** if the battery has not been used (free collection on the Iberian mainland). You will receive tracking by email. ## Frequently asked questions ### How is the Fulbat AUX12 battery installed in the vehicle? In most cars it fits in 15-30 minutes with a 10 mm wrench; if the battery is under the seat or in the boot the time can double. See the step-by-step guide on this page. Quick summary: 1) switch off the engine and remove the key; 2) locate the original battery (engine bay, boot or under seat); 3) disconnect the negative (βˆ’) terminal first, then the positive (+); 4) loosen the hold-down clamp and remove the old battery; 5) fit the new one in the same orientation β€” match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (βˆ’). On cars with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile. ### What is the service life of the AUX12 model? Expected lifespan of the Fulbat AUX12 is 4 to 7 years in regular use (depends on technology and climate). 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 measurements of the AUX12 model? Dimensions (length Γ— width Γ— height) are 150Γ—87Γ—130 mm β€” also written as 150x87x130 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. ### Is the AUX12 valid for my vehicle? 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 16:40–18:00 (Spanish time, CET)). The AUX12 typically fits a wide range of European vehicles thanks to its standard DIN case format. ### Which interchangeable batteries are there for this one? 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. ## 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 2015. β†’ https://baterias.com/gb/technical-team --- *baterias.com β€” Automotive batteries Β· 2026-10-13*