# Boat Batteries > Marine batteries for starter, cabin service and dual purpose. AGM, GEL and LiFePO4 by Fullriver, MK, Trojan, Varta marine and Optima **Category:** [Start](https://baterias.com/gb/beginning) → [Batteries](https://baterias.com/gb/batteries) → [Starter Batteries](https://baterias.com/gb/starter-batteries) - **Canonical URL**: https://baterias.com/gb/boat-batteries - **Language**: en-GB ## Description **Find the battery for your boat** using the finder right below: select your vehicle step by step and see only 100% compatible batteries. Other quick paths: by [number plate](/gb/battery-finder-by-plate), by [part-number](/gb/part-number) from the manufacturer or by the **code printed** on your current battery (Varta E11, Tudor TC700, YTX12-BS, etc.). ## How to choose the right marine battery The most expensive mistake in marine use is fitting a starter battery for service duty: the thin plates of an SLI cannot tolerate deep discharge and sulphate within 4-6 weeks of anchoring. The opposite is just as costly: using a service battery (thick plates) to crank an outboard — it doesn't deliver enough CCA and the starter motor doesn't get the peak it needs in cold water. **Each role demands its own battery.** ### Typical capacities by marine use Use Typical capacity Recommended technology Starter, vessels <6 m 50-80 Ah Marine SLI or AGM dual Starter, vessels 6-12 m 80-130 Ah Marine AGM (vibration-proof) Cabin service (radio, GPS, plotter) 100-200 Ah Deep cycle AGM Large bank (fridge, windlass, autopilot) 200-400 Ah GEL or LiFePO4 Sailing yacht, 3+ day autonomy 400-800 Ah LiFePO4 (low weight, 100% DoD) ### AGM vs GEL vs Lithium in marine **AGM** is the modern standard: sealed, maintenance-free, 90° tilt-tolerant, 4-7 year service life with proper use. **GEL** handles extreme depth-of-discharge better (80% DoD cycles) but charges slower and won't accept fast engine charging. **LiFePO4 lithium** is the premium tier: 4x cycles, 100% usable capacity, a quarter of the weight. 2-3x the upfront cost, but pays back in heavy use. Requires a lithium-compatible charger profile. ### Leading marine brands - [Fullriver DC / DCG / FT](/gb/batteries-fullriver) — world reference in recreational marine, 1,200+ cycles at 50% DoD. - [MK Battery AGM and Gel](/gb/batteries-mk) — sealed, 90° tilt and heavy vibration tolerant. - [Trojan AGM Marine](/gb/batteries-trojan) — premium AGM for large vessels and long-autonomy yachts. - [Varta Professional Dual Purpose AGM](/gb/batteries-varta) — official dual range for small boats. - Optima Blue Top — AGM SpiralCell, top vibration resistance for powerful outboards. ### Frequently asked questions ### **Why not a car battery on my boat?** Standard car batteries (SLI thin plates) deliver high CCA briefly and recharge from the alternator. In marine use, discharges are long and deep — destroying SLI in weeks. You need marine AGM (thicker plates) or deep cycle. ### **Will a dual battery work for engine + cabin?** Only on small boats (<6 m) with modest loads. As soon as equipment grows (fridge, plotter, autopilot), split banks: starter (50-80 Ah AGM) + service (100-200 Ah deep cycle AGM). ### **Is lithium worth it?** For occasional weekend use, no. For liveaboard or long cruises, yes: weight savings and 100% usable capacity (vs 50% lead) pay back in 3-4 years. ### **Returns?** Free 14-day returns for mainland Spain and Portugal if sealed. ### **How long does shipping take?** Standard delivery **1 to 5 working days** to your country. We process orders within 24h. Catalogue curated by our technical team. **11,063 Trustpilot reviews · 4.5/5**. 24h mainland delivery, free 14-day returns. ## Products in this category | Product | Brand | Price | |---|---|---| | [Caravan battery Optima YTS-5.5 12V 75Ah 975A AGM](https://baterias.com/gb/battery-optima-yellow-top-yts-55-8051-187-12v-75ah) | OPTIMA | 260,45 € | | [Marine battery Exide EP800 12V 95Ah 850A AGM](https://baterias.com/gb/battery-exide-ep800-12v-95ah-850a) | EXIDE | 132,65 € | | [Marine battery Varta LA95 12V 85Ah AGM](https://baterias.com/gb/battery-varta-la95agm-12v-95ah-850a) | VARTA | 181,75 € | | [Marine battery Exide EP600 12V 70Ah 760A AGM](https://baterias.com/gb/battery-exide-ep600-12v-70ah-760a) | EXIDE | 104,05 € | | [Marine battery Exide EU80-6 6V 80Ah 600A](https://baterias.com/gb/battery-exide-eu80-6-6v-80ah-600a) | EXIDE | 81,87 € | | [Marine battery Exide EP1200 12V 140Ah 700A AGM](https://baterias.com/gb/battery-exide-ep1200-12v-140ah-700a) | EXIDE | 269,18 € | | [Marine battery Optima BTDC-5.5 12V 75Ah 975A AGM](https://baterias.com/gb/battery-optima-blue-top-btdc-55-8052-188-12v-75ah) | OPTIMA | 263,05 € | | [Marine battery Exide EP450 12V 50Ah 750A AGM](https://baterias.com/gb/battery-exide-ep450-12v-50ah-750a) | EXIDE | 141,15 € | | [Marine battery Varta LA80 12V 77Ah AGM](https://baterias.com/gb/battery-varta-la80agm-12v-80ah-800a) | VARTA | 154,15 € | | [Marine battery Varta LFD140 12V 119Ah](https://baterias.com/gb/battery-varta-lfd140-12v-140ah-800a) | VARTA | 180,72 € | | [Marine battery Exide ER550 12V 115Ah 760A](https://baterias.com/gb/battery-exide-er570-12v-120ah-760a) | EXIDE | 122,65 € | | [Marine battery Optima BTDC-4.2 12V 55Ah 765A AGM](https://baterias.com/gb/battery-optima-blue-top-btdc-42-8016-253-12v-55ah) | OPTIMA | 216,23 € | | [Marine battery Exide ER350 12V 80Ah 570A](https://baterias.com/gb/battery-exide-er350-12v-80ah-510a) | EXIDE | 84,50 € | | [Caravan battery Optima YTS-4.2 12V 55Ah 765A AGM](https://baterias.com/gb/battery-optima-yellow-top-yts-42-8012-254-12v-55ah) | OPTIMA | 213,10 € | | [Marine battery Exide EP900 12V 100Ah 800A AGM](https://baterias.com/gb/battery-exide-ep900-12v-100ah-720a) | EXIDE | 245,30 € | ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team — over 25 years of experience validating automotive batteries. → https://baterias.com/gb/technical-team --- *baterias.com — Automotive batteries · 2026-08-10*