12V 300Ah Cranking & Deep Cycle Lithium Battery (Dual Purpose) - Pro Series

Yes. The Epoch 12V 300Ah Group 8D LiFePO4 battery is designed for both engine starting and deep-cycle power applications. It delivers up to 1,000A of peak discharge for 5 seconds and 800A for 10 seconds, providing the power needed to start compatible marine engines. Epoch specifically notes compatibility with Mercury 250 hp motors when the electrical system is properly matched. In addition to starting power, the battery provides 300Ah of capacity for electronics, trolling motors, lighting, and other onboard equipment. Always verify compatibility with your engine and charging system before installation.

In many compatible marine systems, no. A 12V 300Ah dual-purpose lithium battery combines engine-starting power and deep-cycle energy storage in a single unit. It can power fish finders, bilge pumps, lighting, marine audio, refrigeration, and other 12V accessories while still providing the cranking power needed to start compatible marine engines. Always verify compatibility with your electrical system before installation.

Yes, this battery is designed around a Group 8D marine battery footprint. Epoch lists the dimensions as 19.70 in L × 10.5 in W × 9.75 in H (500 × 267 × 248 mm), and it must be mounted upright. If you currently run a Group 8D lead-acid or AGM battery, this lithium upgrade is intended to fit the same class of tray, but you should still verify tray dimensions, hold-downs, lid clearance, terminal access, and cable reach before ordering.

The Epoch 12V 300Ah Group 8D lithium battery weighs 81 lbs. Many traditional Group 8D lead-acid or AGM batteries weigh roughly 130 to 160 lbs, so it is about 49 to 79 lbs lighter. Less stern weight can help improve boat balance, hole shot, draft, and fuel efficiency depending on the vessel.

Yes. Epoch lists this Pro Series model as supporting up to 16 batteries in parallel for expanded 12V capacity and up to 4 batteries in series for 24V, 36V, or 48V systems. With batteries in series, up to 4 strings may be paralleled (4S4P maximum: 51.2V, 1,200Ah, 61.44kWh). Use matched batteries of the same model, age, capacity, and state of charge, check that their voltages are within 0.5V before connecting, and follow Epoch’s series/parallel, communication, fusing, and charger guidance.

No. Its IP67 enclosure is dust-tight and protected against temporary immersion to 1 m for 30 minutes, but the manual says not to install it where standing water can collect around the case or terminals, such as a bilge, and not to submerge or pressure-wash it. Mount it upright in a clean, dry, ventilated compartment, secured with its bracket, with a DC-rated main fuse close to the positive terminal.

Yes. Bluetooth monitoring is built in, so you can use the free Epoch Pro app on an iOS or Android device to view battery information such as state of charge, voltage, current, temperature, and battery status. The Pro Series also supports over-the-air firmware updates through the app.

Through the Pro Series communications box. The battery has CAN Link in and Link out ports for networking a bank; for Victron systems or NMEA 2000 networks, Epoch offers the Pro Series communications box. Contact Epoch for configuration support.

Yes. It has internal heating. When a charger is connected in cold weather, the heater warms the battery to 10°C (50°F) and then switches to charging, so it charges down to -20°C (-4°F); leave the charger connected and allow up to 60 minutes. It discharges down to -20°C (-4°F).

Use a lithium-compatible charger, inverter charger, converter, solar charge controller, or DC-to-DC charger programmed for LiFePO4 batteries. The Epoch 12V 50A Lithium Battery Charger is compatible. Epoch’s recommended settings are 14.2V bulk/absorption (14.2V–14.6V range), 13.8V float (13.4V–13.8V range; float off is preferred where the charger allows), equalization disabled, temperature compensation disabled, and up to 150A charge current (300A maximum from all sources combined). 15.4V is a listed maximum, not a charger target. For alternator charging, use a DC-to-DC charger or lithium-ready regulation where the engine maker allows it.

This battery stores 3,840Wh (nominal; plan on about 3,072Wh) and is rated for 6,000+ cycles at 0.2C and 80% depth of discharge, to 80% of initial capacity at 25°C. It also handles engine cranking (1,000A for up to 5 seconds) and weighs 81 lb, against 130–160 lb for a lead-acid 8D.

This dual-purpose battery is built for marine engine starting plus deep-cycle house power: electronics, sonar, pumps, refrigeration and lighting on dual-purpose boats, RV, van and overland 12V systems, 3,000W-class inverter systems within 300A, solar, off-grid, cabin and backup power, and 24V to 48V banks. At 500W it runs about 6.1 hours, and at 1,000W about 3.1 hours. Its large energy capacity supports extended runtimes for appliances, electronics, and essential equipment. The battery’s lightweight LiFePO4 design, long cycle life, and reliable performance make it a practical choice for demanding energy needs.