# Marine battery Tudor TZ850 12V 100Ah 900A EFB ![Marine battery Tudor TZ850 12V 100Ah 900A EFB](https://baterias.com/4658-home_default/battery-tudor-tz850-12v-100ah.jpg) > Tudor TZ850 marine battery 12V 100Ah 900A EFB. Marina & Leisure Dual EFB range. Dimensions 353×175×190 mm, + terminal on the right. Cranking and house duties. **Category:** [Boat Batteries](https://baterias.com/gb/boat-batteries) → [TUDOR](https://baterias.com/gb/tudor) - **Canonical URL**: https://baterias.com/gb/battery-tudor-tz850-12v-100ah - **Language**: en-GB - **Brand**: TUDOR - **Reference**: BCOM-TUDOR-TZ850 - **EAN**: 3661024057608 - **MPN**: TZ850 - **Price**: 146,20 € - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Largo | 353 mm | | Ancho | 175 mm | | Alto | 190 mm | | Peso | 25.5 kg | | Tecnología | EFB | | EAN | 3661024057608 | | Terminal layout | Positive right | | Terminal type | EN taper post | | Hold down | B13 | | Cold cranking amps (EN) | 900 A | | Capacity (C20) | 100 Ah (c20) | ## Quick description **Tudor TZ850 100Ah 900A** is a marine battery with reinforced anti-vibration case for moorings and offshore use. Tolerates the typical daily cycles on a boat (engine start + night-time services such as lights, sonar, fridge) and holds voltage even when the hull is rolling in open sea. ## 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 ⚡ Capacity 100 Ah C20 🔋 Cold cranking 900 A EN-1 📏 Dimensions 353×175×190 mm ⚙️ Technology EFB 🧭 Polarity Positive on the right ⚖️ Weight 25,5 kg ## Description ## Marine battery Tudor TZ850 100Ah 900A 12V 12*V* Voltage 100*Ah* Capacity 900*A* Cold cranking 25.50*kg* Weight The **Tudor TZ850** with EFB technology is a marine battery with **100 Ah** and **900 A** of cold cranking current (EN) for motor and sailing boats, both for engine starting and onboard services. Its 353 × 175 × 190 mm and the positive terminal on the right make it the exact replacement for the 100 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. - EFB: the evolution of the conventional battery for basic Start-Stop cars. ### What the Tudor TZ850 is for On board, the Tudor TZ850 provides 100 Ah with a case reinforced against vibration and swell. Keep the terminals clean and protected from salt humidity. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 25.50 kg, EN taper post terminals and B13 hold-down. ### Technology inside the Tudor TZ850 The TZ850 is one of the Tudor references for this type of use; it shares the same manufacturing and quality-control criteria as the rest of the brand's catalogue. EFB (Enhanced Flooded Battery) technology reinforces the conventional lead-acid battery with a polyester separator and carbon additives in the plates. It withstands many more start cycles and partial discharges, making it ideal for basic Start-Stop and intensive use. ### Size, terminals and hold-down of the Tudor TZ850 The Tudor TZ850 is made in the 353 × 175 × 190 mm format and weighs 25.50 kg. The positive terminal on the right 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 B13 hold-down and EN taper post 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. ### Why choose Tudor batteries Tudor is Spain's historic battery brand, today part of the Exide group. Its car, truck, motorcycle and leisure ranges are built with the same technology and controls as the group's original-equipment references. All the Tudor batteries in our catalogue are genuine product, recently manufactured and covered by the manufacturer's warranty. ### Usage and maintenance tips A charger with an EFB or smart conventional mode is enough; avoid the high-voltage modes intended for AGM. At the end of the season, charge the battery fully and, if possible, keep it on a charger over the winter lay-up. ### Warranty and coverage The Tudor TZ850 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 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 ### How is the Tudor TZ850 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 Tudor TZ850 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 dimensions of the Tudor TZ850 battery? Dimensions (length × width × height) are 353×175×190 mm — also written as 353x175x190 mm and correspond to the European L5 case size — 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. ### Will the Tudor TZ850 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 TZ850 typically fits a wide range of European vehicles thanks to its standard DIN case format. ### Which batteries are equivalent to the Tudor TZ850? 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. ## 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 · 2026-10-06*