If you run a boat, a large RV, or an off-grid system you already know the frustration. Two battery banks to manage. Heavy, bulky lead-acid batteries that need constant attention. Voltage that sags under load right when you need it most. A starting battery that takes up space but only gets used for five seconds at a time.

The Epoch 12V 300Ah Pro Series Dual Purpose LiFePO4 Battery was built to eliminate all of that.

This is a single Group 8D battery that does what most batteries can't it cranks your engine and powers your house loads, from the same unit, without compromise. With 1,000A of peak cranking power and 300Ah of deep cycle capacity, it replaces a two-bank lead-acid system and fits directly into the same footprint.

It's fully sealed to IP67 waterproof and dustproof. It has an internal self-heating system that allows charging down to -4°F. It talks natively to Victron equipment via CAN bus. And you can monitor everything from your phone via Bluetooth.

This is the battery serious boaters, RV owners, and off-grid builders move to when they're done replacing lead-acid every two years.

• 3.84 kWh of usable energy in a single Group 8D package
• 6,000+ cycles at 80% depth of discharge  built to last over a decade
• 81 lbs  roughly half the weight of a comparable lead-acid Group 8D
• 11-year Epoch manufacturer warranty
• Certified: UL1973, RoHS, CE

Key Benefits

Most battery upgrades improve one thing. This one changes how your entire power system works.

• One battery replaces two
  Stop managing a separate starting battery and house bank. The 12V 300Ah Pro Series handles both engine cranking and sustained house loads from a single unit. Less wiring, less complexity, less to maintain.
• Nearly twice the usable power of a same-size AGM
  A 300Ah AGM delivers roughly 150Ah of usable energy before you risk damaging it. This battery gives you 240–270Ah of usable energy from the same 300Ah rating because LiFePO4 safely discharges to 80–90%. That's the difference between running out at 9 PM and running through the night.
• Voltage stays flat under load no more sag
  Lead-acid batteries lose voltage as they discharge. LiFePO4 holds a stable voltage curve throughout the discharge cycle. Your electronics, trolling motor, and inverter get consistent power from full to empty.
• Charges dramatically faster
  A lead-acid bank this size can take 10–12 hours to fully recharge. This battery accepts up to 300A of charge current. With a properly sized charger, that means less time at the dock and more time on the water.
• Know exactly what your battery is doing from your phone
  Built-in Bluetooth connects to the Epoch app on iOS or Android. Real-time voltage, current, state of charge, and cell temperature all visible from your phone. No guessing. No analog gauges. No surprises when you're already underway.
• Works in cold weather without babysitting
  The internal self-heating system activates automatically when temperatures drop, allowing safe charging down to -4°F. You don't have to do anything. It handles itself.
• Fits where your current battery already sits
  Group 8D form factor means it drops directly into your existing battery tray. No modifications, no custom mounts, no fabrication required for most installs.
• One purchase instead of five over a decade
  A quality Group 8D AGM costs $300–$500 and lasts 2–3 years under regular use. Over 10 years, you replace it 3–5 times spending $1,000–$2,500 plus labor and inconvenience. This battery is rated for 6,000+ cycles, which at daily use is well over a decade of service.

Is This Battery Right for You?

This battery was designed for demanding power systems that need reliability, not just capacity. Here's how to know if it's the right fit.

This is the right battery if you:

• Own a boat with a large outboard or inboard engine and currently run two separate battery banks
• Want to simplify your marine electrical system without giving up starting power
• Run a Victron-based system and need native CAN bus integration
• Boat or camp in cold climates where charging below freezing is a regular concern
• Are replacing one or more Group 8D lead-acid batteries and want a direct drop-in upgrade
• Run heavy loads inverters, electric windlasses, refrigeration, air conditioning, or multiple trolling motors
• Want to monitor your battery remotely from a smartphone without adding external monitors
• Are building an off-grid solar system that needs both cranking capability and deep storage
• Are tired of replacing lead-acid batteries every 2–3 years

Does this sound like you?

• The serious boater / offshore angler Runs a 22–32 ft center console, bay boat, or offshore vessel with a large Mercury, Yamaha, or Volvo Penta engine. Currently managing two battery banks. Values reliability above everything else and cannot afford electrical failures offshore.
• The sailboat cruiser Needs serious house bank capacity for instruments, autopilot, refrigeration, lighting, and communication gear during passages. Has or is building a Victron system. Wants to simplify the electrical layout and reduce weight.
• The RV boondocker Travels full-time or seasonally. Wants to run the inverter, CPAP, refrigerator, and lighting without a generator. Already has or plans to install Victron equipment.
• The off-grid builder Building a cabin, container home, or van conversion on a Victron backbone. Needs maximum capacity per battery slot with native ecosystem communication.

This battery may not be the right fit if you:

• Only need a dedicated trolling motor battery smaller, lighter options serve that purpose better
  
• Need native 24V, 36V, or 48V voltage this is a 12V battery
• Rarely discharge below 50% and are on a tight budget an AGM may be sufficient for very light use

Sound Familiar?

Every feature on this battery exists because someone had a real problem that a standard battery couldn't fix. If any of these sound like your situation, you're in the right place.

• "I'm tired of managing two separate battery banks"
  Most marine and RV setups require a dedicated starting battery plus a house bank two battery types, two chargers, isolators, more wiring, more things to fail. The dual-purpose design combines both into one battery with a single bank to manage.
  
  
• "My AGM runs out of usable power too quickly"
  Lead-acid batteries are limited to roughly 50% depth of discharge. On a 300Ah AGM, that's 150Ah of actual usable energy. This battery delivers 240–270Ah of usable energy from the same capacity rating. Customers report running 12V air conditioners for several hours and eliminating the generator overnight.
  
  
• "I keep buying the same battery every 2–3 years"
  Group 8D AGM batteries under regular use typically last 2–3 years. This battery is rated for 6,000+ cycles at 80% depth of discharge  over a decade of service from one purchase.
  
  
• "My battery is too heavy and throws off my boat's trim"
  A comparable Group 8D lead-acid battery weighs 130–160 lbs. This battery weighs 81 lbs. On a boat, that's 50–80 lbs removed from the transom or bilge which directly affects trim, fuel efficiency, and performance.
  
  
• "I can't charge my lithium battery in cold weather"
  Standard LiFePO4 batteries cannot be safely charged below 32°F. The internal self-heating system on this battery solves that problem automatically. It activates when temperatures drop and allows safe charging down to -4°F without any action from you.
  
  
• "I never know my battery's real state until it's too late"
  Analog voltage gauges are poor indicators of LiFePO4 state of charge. The built-in Bluetooth gives you exact voltage, current, SOC percentage, and cell temperature on your phone in real time  before you leave the dock or campsite.
  
  
• "My battery doesn't communicate with my Victron equipment"
  Many lithium batteries require expensive third-party adapters to integrate with Victron equipment. This battery communicates natively via CAN bus the Victron ecosystem recognizes it immediately, no adapters needed.
  
  
• "My battery compartment gets wet and I'm worried about damage"
  Standard batteries are not waterproof. The IP67 rating means this battery handles submersion up to 1 meter for 30 minutes and regular exposure to bilge splash, spray, and condensation without damage.

Features

Here's what's inside this battery, why it's there, and what it means for you in real use.

• Dual-Purpose Design  Cranking + Deep Cycle
  What it does: Delivers 1,000A peak for 5 seconds to start your engine, and 300A continuous to power your house loads all day. One battery replaces two.
  
  
• LiFePO4 Chemistry
  What it does: Lithium Iron Phosphate is the safest, most thermally stable lithium chemistry for marine and RV use. No thermal runaway. No off-gassing. Safe in enclosed compartments.
  
  
• Internal Self-Heating System
  What it does: Activates automatically in cold conditions and allows safe charging down to -4°F (-20°C). Other lithium batteries can't charge below 32°F without external heat management this one handles it internally.
  
  
• Victron CAN Bus Communication
  What it does: Connects natively to Cerbo GX, MultiPlus, Quattro, and SmartSolar MPPT via CAN bus and RS485. The full battery string communicates as one unified system. No third-party adapters required for Victron setups.
  
  
• Bluetooth Monitoring  iOS and Android
  What it does: Free Epoch app shows real-time voltage, current, state of charge, and cell temperature. Over-the-air BMS firmware updates delivered through the same app.
  
  
• IP67 Waterproof and Dustproof
  What it does: Fully sealed against dust and water submersion up to 1 meter for 30 minutes. Built for bilges, exposed decks, and open battery compartments.
  
  
• Advanced Battery Management System (BMS)
  What it does: Monitors and protects every cell in real time. Guards against overcharge, over-discharge, short circuit, overcurrent, and temperature extremes. Contains proprietary software for compatibility with Mercury 250 hp outboard motors and other major engine brands.
  
  
• 300A Continuous Charge and Discharge
  What it does: Handles large inverters, multiple high-draw electronics, electric windlasses, and air conditioning loads simultaneously without the battery restricting output.
  
  
• 6,000+ Cycle Life at 80% DoD
  What it does: At one full cycle per day, that's over 16 years of service. A comparable Group 8D AGM lasts 2–3 years under the same conditions.
  
  
• Group 8D Form Factor
  What it does: Matches standard Group 8D dimensions (19.70" x 9.84" x 9.06") for direct drop-in replacement with no tray modifications in most installs.
  
  
• Scalable Bank Configuration
  What it does: Up to 4 in series (48V) or up to 16 in parallel (4,800Ah at 12V). Start with one and expand as your needs grow.

Why This Battery

You have options. Here's an honest look at how this battery compares to what you may already be considering.

vs. Group 8D AGM Lead-Acid

• A Group 8D AGM costs $300–$500 but only delivers ~50% of its rated capacity as usable energy and typically lasts 2–3 years
• The 12V 300Ah Pro Series delivers 80–90% usable capacity, lasts 6,000+ cycles, and weighs roughly half as much
• AGM cannot charge below 32°F this battery charges down to -4°F with internal heating
• AGM voltage sags under load LiFePO4 holds a flat discharge curve throughout
• Over 10 years, multiple AGM replacements often exceed the cost of one lithium battery

vs. Standard Deep Cycle LiFePO4 Batteries

• Most lithium batteries are designed purely for deep cycle use — they are not rated for engine cranking
• This battery is specifically designed and tested for both cranking and deep cycle in one unit
• Many basic lithium batteries lack internal heating, Victron communication ports, and IP67 waterproofing all standard here

vs. Running Separate Start + House Banks

• Two banks mean two chargers, battery isolators or combiners, more wiring, and more failure points
• One dual-purpose battery simplifies the entire system one bank, one charger profile, one monitoring app
• You recover the physical space the second battery occupied

vs. Epoch Essential Series

• The Essential Series offers deep cycle performance at a lower price point
• The Pro Series adds engine cranking capability, higher peak discharge, native Victron CAN bus communication, and IP67 waterproofing
• If your application requires engine starting, the Pro Series dual-purpose design is the appropriate choice

What's Included

In the Box

• 1x Epoch 12V 300Ah Pro Series Dual Purpose LiFePO4 Battery (SKU: DP12300H)
• Owner's manual and documentation

Important. Not Included:

• Mounting brackets are not included source Group 8D-compatible hardware separately before installation
• No internal fuse install an appropriate external fuse or circuit breaker sized for your system

Optional Pro Series Accessories

The 12V 300Ah Pro Series is designed to work with two optional accessories that significantly expand what your system can do. Neither is required to operate the battery but both are worth understanding before you finalize your build.

1. Pro Series 5" Touch Screen Display

The Epoch app gives you remote monitoring from your phone. But what if you want a permanent dashboard mounted at the helm, in the cabin, or on your RV wall always visible, no phone required?

The 5" Touch Screen Display is a dedicated panel monitor built specifically for the Pro Series battery system.

• 5.0-inch LCD touchscreen 800x480 resolution, 262K true-color display
• Shows voltage, current, state of charge, remaining capacity, min/max cell temperature, and system warnings in real time
• Built-in speaker, LED lamp, and photosensitive sensor
• ABYC E-13 compliant  audible alert triggers automatically when a system warning occurs
• Configure inverter protocol settings directly from the screen
• Works in conjunction with the Communications Box for expanded system control

Who needs this: Boaters who want helm-mounted battery monitoring without pulling out a phone. RV owners who want a wall-mounted display in their living area. Charter and commercial operators where ABYC compliance is relevant. Anyone who wants always-on visual confirmation of battery status at a glance.

2. Pro Series Communications Box

The battery's built-in CAN bus port connects natively to Victron. But what if you're running a different inverter brand or you need your battery data to appear in your chartplotter via NMEA-2000?

The Communications Box is the bridge that connects your Pro Series battery system to virtually any inverter brand and to NMEA-2000 marine networks.

• Supports CAN, RS485, and LIN communication protocols
• Meshes multiple Pro Series batteries together for unified monitoring and control across a large bank
• Configure inverter protocols via the Bluetooth app or the 5" Touch Screen Display
• NMEA-2000 compatible integrates battery data into your chartplotter and marine electronics network
• RV-C compatible works with RV-standard communication networks
• Compatible inverter brands: Victron, Schneider, Sol-Ark, Growatt, Goodwe, Solis, Deye, SAJ, Megarevo, INVT, Sermatec, TBB, SUNGOLDPOWER SG, Sunsynk, SMA, Studer Innotec, Sofar, Voltronic, SUNGOLDPOWER SPH, RCT, MPP Solar, Alpha Outback, Phocos

Who needs this: Anyone running a non-Victron inverter who wants full battery-to-inverter communication. Marine builders integrating battery data into a NMEA-2000 chartplotter network. Anyone building a large multi-battery bank who wants centralized monitoring across all units.

Note: For Victron-only systems, the battery's native CAN bus port is sufficient the Communications Box is optional. It is required for NMEA-2000 integration or non-Victron inverter communication.

Specifications

All specifications sourced directly from Epoch Batteries manufacturer documentation.

Recommended Charging Parameters

Installation

Most installations are straightforward this is a Group 8D drop-in. Here's what you need to know before you start.

Before You Install

• Confirm your battery tray fits Group 8D dimensions: 19.70" L x 9.84" W x 9.06" H
• Source mounting brackets separately not included with the battery
• Install an appropriate external fuse or circuit breaker no internal fuse on this model
• Verify your charger(s) can be programmed for LiFePO4 at the voltages listed in the Specifications tab
• If charging from your alternator, route through a DC-to-DC charger (such as a Victron Orion) to protect both alternator and battery

Charger Programming

• Bulk/Absorption voltage: 14.2V – 14.6V
• Float voltage: 13.4V – 13.8V
• Disable Equalization
• Disable Temperature Compensation
• Confirmed compatible brands: Epoch, NOCO Gen Pro, Dual Pro PS/Auto, Minnkota Precision, Pro Mariner / Pro Tournament Elite, Stealth, Troll Bridge DC, Power Pole

Bluetooth Setup

• Download the free Epoch app from the iOS App Store or Google Play
• Enable Bluetooth and open the app the battery pairs automatically
• Confirm all cell readings are within normal range after pairing
• BMS firmware updates are delivered over the air through the app

Victron Integration

• Connect the battery CAN bus port to your Victron Cerbo GX, MultiPlus, or MPPT using a CAN bus cable
• The battery is recognized natively no additional configuration tools required for Victron-only systems
• For NMEA-2000 or non-Victron inverter integration, the optional Pro Series Communications Box is required

First Use

• Perform one full charge and discharge cycle before relying on the battery for critical loads
• Minor cell imbalance on arrival from shipping is normal one cycle corrects this automatically
• Verify all cell readings are balanced in the Epoch app after the first cycle

Storage

• Store between 32°F and 95°F (0°C to 35°C)
• Never store in a fully discharged state this voids the warranty
• Store at a partial state of charge during extended non-use periods
• Do not leave the internal heater active overnight without a charging source connected

FAQ