Optima BTSLI-4.2 Blue Top · Marine battery 50Ah 815A AGM

Marine battery Optima BTSLI-4.2 Blue Top 50Ah 815A 12V

The Optima BTSLI-4.2 marine battery offers 12 V, 50 Ah and 815 A of cold cranking current (EN) from the Blue Top range with spiral-cell AGM technology, designed for motor and sailing boats, both for engine starting and onboard services. Measuring 254 × 172 × 173 mm and the positive terminal on the left, it is the direct replacement for boats fitted from the factory with a 50 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.

Vehicles compatible with the Optima BTSLI-4.2

The Optima BTSLI-4.2 is compatible with more than 58 vehicles: it is fitted as original equipment or as a replacement by brands such as Fendt, Deutz-Fahr, New Holland, Ford, International-Harvester and Inter Harv.. It is a go-to option when you need a battery for a Fendt, Deutz-Fahr or other models that use this same format. Models from Isuzu and Jeep are added to that list.

Dimensions, polarity and mounting

The Optima BTSLI-4.2 is made in the 254 × 172 × 173 mm format and weighs 18 kg. 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 1 & 21 terminals, the system that anchors and connects it in the vehicle. Checking the three dimensions and the terminal position before buying avoids the most common mistake when replacing a battery.

What Optima does differently

The Optima Red, Yellow and Blue Top are references for high-performance starting, deep cycling and marine use respectively, all with the characteristic six spiral-cell design. All the Optima batteries in our catalogue are genuine product, recently manufactured and covered by the manufacturer's warranty.

The Optima BTSLI-4.2: Blue Top range and spiral-cell AGM technology

Within the Optima catalogue, the Blue Top series groups the references designed for this use. The BTSLI-4.2 is the 50 Ah model of that family, with the same performance as its siblings in other sizes.

In a spiral-cell battery the electrolyte is absorbed and the plates are wound under pressure. That lets it deliver very high current peaks, recharge quickly and be mounted in any position.

How to make it last longer

As a service battery, avoid routine discharges below 50% to extend its cycle life. Charge with a voltage-controlled AGM charger; a fully discharged pure-lead battery may need a specific charger to recover.

Manufacturer's warranty

The Optima BTSLI-4.2 comes with the manufacturer's official warranty against manufacturing defects. Deep discharge from winter lay-up without charging is not covered.

Shipping, delivery and returns

Orders placed before 6:00 pm with the battery in stock ship the same day. Delivery in mainland Spain and Portugal takes 24-48 working hours; for the Balearic Islands and the rest of the European Union allow 3 to 5 working days. You have 14 days to return an unused battery; in mainland Spain and Portugal collection is free. We email you the tracking number as soon as the parcel ships.