# Marine battery Optima BTDC-5.5 12V 75Ah 975A AGM ![Marine battery Optima BTDC-5.5 12V 75Ah 975A AGM](https://baterias.com/3804-home_default/battery-optima-blue-top-btdc-55-8052-188-12v-75ah.jpg) > Optima BTDC-5.5 marine battery 12V 75Ah 975A AGM. BLUE TOP range. Dimensions 325×165×238 mm. Cranking and house duties. **Category:** [Boat Batteries](https://baterias.com/gb/boat-batteries) → [OPTIMA](https://baterias.com/gb/optima) - **Canonical URL**: https://baterias.com/gb/battery-optima-blue-top-btdc-55-8052-188-12v-75ah - **Language**: en-GB - **Brand**: OPTIMA - **Reference**: BCOM-OPTIMA-BTDC-5.5 - **EAN**: 4016987113592 - **MPN**: BTDC-5.5 - **Price**: 263,70 € - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | OPTIMA | | Reference | BTDC-5.5 | | Model | OPTIMA BLUE TOP | | Voltage (V) | 12 V | | Largo | 325 mm | | Ancho | 158 mm | | Alto | 218 mm | | Peso | 27.9 kg | | Tecnología | AGM ESPIRAL | | EAN | 4016987113592 | | Terminal layout | 8 | | Terminal type | 1 & 21 | | Cold cranking amps (EN) | 975 A | | Capacity (C20) | 75 Ah (c20) | | Capacity (C5) | 68 Ah (c5) | | ETN | 8521880008882 | ## Quick description **Optima BTDC-5.5 12V 75Ah 975A** is a marine battery, vibration- and deep-discharge resistant, suitable both for outboard engine starting and for onboard auxiliary services (navigation lights, GPS, sonar, fridge). Sealed and maintenance-free. ## Why this marine battery? - **Marine design** built for boat swell and vibration - **Dual function** starts the engine and powers onboard services - **Sealed and safe** maintenance-free even when the boat rolls 🔌 Voltage 12 V ⚡ Capacity 75 Ah C20 🔋 Cold cranking 975 A EN-1 📏 Dimensions 325×165×238 mm ⚙️ Technology AGM ESPIRAL ⚖️ Weight 27,9 kg 🏷️ Model OPTIMA BLUE TOP ## Description ## Marine battery Optima BTDC-5.5 Blue Top 75Ah 975A 12V 12*V* Voltage 75*Ah* Capacity 975*A* Cold cranking 27.90*kg* Weight The **Optima BTDC-5.5** with spiral-cell AGM technology is a marine battery with **75 Ah** and **975 A** of cold cranking current (EN) for motor and sailing boats, both for engine starting and onboard services. Measuring 325 × 158 × 218 mm, it is the direct replacement for boats fitted from the factory with a 75 Ah battery of this format. - Sealed: no spills or gases in the locker. - Resistant to humidity and salt air. - Spiral AGM construction, sealed and mountable in any position. - Ready for starting outboard and inboard engines. ### What the Optima BTDC-5.5 is for The Optima BTDC-5.5 is designed for motor and sailing boats, both for engine starting and onboard services. If it is your starter battery, run the services from a separate battery; if it is a service battery, avoid routinely discharging it beyond 50%. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 27.90 kg and 1 & 21 terminals. ### Will it fit your current battery tray? In terms of format, the Optima BTDC-5.5 measures 325 × 158 × 218 mm (length × width × height) and weighs 27.90 kg. It uses 1 & 21 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. ### The Optima BTDC-5.5: Blue Top range and spiral-cell AGM technology Within the Optima catalogue, the **Blue Top** series groups the references designed for this use. The BTDC-5.5 is the 75 Ah model of that family, with the same performance as its siblings in other sizes. Spiral AGM construction winds the plates into cylindrical pure-lead cells: maximum active surface, extreme vibration resistance and cranking current far above a battery of the same size. ### Optima: the maker behind the BTDC-5.5 Optima makes spiral-cell (SpiralCell) AGM batteries with pure lead: maximum vibration resistance, very powerful cranking and a durability recognised in 4x4, motorsport, marine and car audio. We guarantee that every Optima arrives new, charged and with the manufacturer's full warranty. ### Official warranty The Optima BTDC-5.5 comes with the **manufacturer's official warranty** against manufacturing defects. Deep discharge from winter lay-up without charging is not covered. ### Usage and maintenance tips Protect the terminals with dielectric grease and check the fixing: vibration and swell loosen connections. Charge with a voltage-controlled AGM charger; a fully discharged pure-lead battery may need a specific charger to recover. ### Shipping, delivery and returns Order **before [[ks:cutoff]]** 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 **[[ks:return_days]] 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 BTDC-5.5 model AGM? What does this technology offer? Yes. The BTDC-5.5 from Optima 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 boats with advanced Start-Stop and regenerative braking. Expected lifespan: 5-8 years under normal conditions. ### How is the Optima BTDC-5.5 battery installed in the vehicle? In most boats 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 (−) 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 — match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (−). On boats with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile. ### How many years does this battery last? Expected lifespan of the Optima BTDC-5.5 is 5 to 8 years in mild-climate boat 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 Optima BTDC-5.5 battery? Dimensions (length × width × height) are 325×165×238 mm — also written as 325x165x238 mm — following the European DIN standard. Always measure the space in your boat before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals. ### What ETN and EAN codes does the Optima BTDC-5.5 battery have? The manufacturer reference (MPN) is BTDC-5.5 and its ETN code is 8521880008882 (short form 852 188 000), the European identifier used in spare-part catalogues. The EAN-13 barcode is 4016987113592. It belongs to the OPTIMA BLUE TOP range. Any of these codes identifies exactly this battery when requesting quotes or comparing prices. ### Will the Optima BTDC-5.5 battery fit my boat? 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 — we reply during business hours (Mon–Fri 10:00–13:30 and 16:40–18:00 (Spanish time, CET)). The BTDC-5.5 fits 2 verified vehicle versions in our database. ### What are the equivalents of the BTDC-5.5 model? 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 — an EFB cannot be replaced with a conventional battery in Start-Stop boats. See the "Equivalents" section to view recommended options at the same performance level. ## Compatible vehicles This battery fits 2 vehicles. 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