# Marine battery Fulbat FDM12-825-M31 12V 105Ah 825A AGM CARBON ![Marine battery Fulbat FDM12-825-M31 12V 105Ah 825A AGM CARBON](https://baterias.com/6392-home_default/battery-fulbat-fdm12-825-m31-12v-105ah-825a.jpg) > Fulbat FDM12-825-M31 marine battery 12V 105Ah 825A AGM CARBON. FDM Marine AGM Carbon range. Dimensions 330Γ—173Γ—237 mm, + terminal on the left. **Category:** [Marine Dual Purpose Batteries](https://baterias.com/gb/marine-dual-purpose-batteries) β†’ [FULBAT](https://baterias.com/gb/fulbat) - **Canonical URL**: https://baterias.com/gb/battery-fulbat-fdm12-825-m31-12v-105ah-825a - **Language**: en-GB - **Brand**: FULBAT - **Reference**: BCOM-FULBAT-FDM12-825-M31 - **MPN**: FDM12-825-M31 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | FULBAT | | Model | FULBAT FDM Marine AGM Carbon | | Voltage (V) | 12 V | | Largo | 330 mm | | Ancho | 173 mm | | Alto | 237 mm | | TecnologΓ­a | AGM Carbon | | Terminal layout | Positive left | | Terminal type | DT | | Cold cranking amps (EN) | 825 A | | Capacity (C20) | 105 Ah | ## Quick description **Fulbat FDM12-825-M31 12V 105Ah 825A** is a quality battery with official manufacturer warranty, confirmed stock and 24-48 h delivery across the peninsula. ## Why this battery? - **Tested and certified** to European EN standards for maximum reliability - **Sealed and maintenance-free** ready to use out of the box - **Long working life** optimised for its real-world use case πŸ”Œ Voltage 12 V ⚑ Capacity 105 Ah C20 πŸ”‹ Cold cranking 825 A EN-1 πŸ“ Dimensions 330Γ—173Γ—237 mm βš™οΈ Technology AGM 🧭 Polarity Positive on the left ## Description ## Marine battery Fulbat FDM12-825-M31 105Ah 825A 12V 12*V* Voltage 105*Ah* Capacity 825*A* Cold cranking The **Fulbat FDM12-825-M31** with AGM technology is a marine battery with **105 Ah** and **825 A** of cold cranking current (EN) for motor and sailing boats, both for engine starting and onboard services. Its 330 Γ— 173 Γ— 237 mm and the positive terminal on the left make it the exact replacement for the 105 Ah battery fitted as standard to many boats. - Resistant to humidity and salt air. - Sealed: no spills or gases in the locker. - Ready for starting outboard and inboard engines. - AGM: faster recharging and better cycle resistance than a conventional battery. ### What the Fulbat FDM12-825-M31 is for With 105 Ah, the Fulbat FDM12-825-M31 covers motor and sailing boats, both for engine starting and onboard services. At the end of the season, charge it fully before winter storage. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has DT terminals. ### Dimensions, polarity and mounting It has external dimensions of 330 Γ— 173 Γ— 237 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. It uses DT terminals, the system that anchors and connects it in the vehicle. 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. ### Fulbat: the maker behind the FDM12-825-M31 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. All the Fulbat batteries in our catalogue are genuine product, recently manufactured and covered by the manufacturer's warranty. ### Technology inside the Fulbat FDM12-825-M31 Within the Fulbat catalogue, the FDM12-825-M31 is the 105 Ah model designed for this application. AGM means the acid is held in a glass mat instead of floating free. That is why the battery can be installed in the cabin without gases, survives more cycles and recovers its charge quickly. ### Care and maintenance At the end of the season, charge the battery fully and, if possible, keep it on a charger over the winter lay-up. Protect the terminals with dielectric grease and check the fixing: vibration and swell loosen connections. ### Warranty and coverage The Fulbat FDM12-825-M31 comes with the **manufacturer's official warranty** against manufacturing defects. Deep discharge from winter lay-up without charging is not covered. ### Delivery times 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 do I fit the FDM12-825-M31 model in my car? 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. ### How long does the Fulbat FDM12-825-M31 battery last? Expected lifespan of the Fulbat FDM12-825-M31 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 FDM12-825-M31 model? Dimensions (length Γ— width Γ— height) are 330Γ—173Γ—237 mm β€” also written as 330x173x237 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 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€” over 25 years of experience validating automotive batteries. β†’ https://baterias.com/gb/technical-team --- *baterias.com β€” Automotive batteries Β· 2026-10-08*