ECO Battery
ECO Battery makes lithium iron phosphate (LiFePO4) batteries for marine and RV use, built for boaters who want to replace heavy lead-acid batteries with something lighter and longer-running. We currently carry ECO Battery’s 12V 120Ah RV & Marine battery, a versatile deep-cycle battery that works for 12V trolling motors, as part of a 24V or 36V series bank where the manufacturer allows, or as a house battery for lights, pumps and electronics.
The ECO Battery 12V 120Ah comes in a Group 31 footprint, a common size for marine battery boxes, which makes it a practical swap for many existing Group 31 lead-acid batteries. It includes Bluetooth monitoring, so you can check state of charge and battery status from a phone app. Internal heating lets the battery warm its cells before charging in freezing temperatures. The product page lists ECO Battery’s published specs, including weight and ingress protection.
We ship nationwide and install anywhere from Venice to Gainesville, FL. If you’re comparing it with other 12V lithium batteries, browse our full Lithium collection.
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Where the ECO Battery 12V 120Ah fits
12V trolling motors
For a 12V bow-mount or transom motor, one 12V lithium battery with healthy capacity can deliver a full day of fishing for many anglers. Your result depends on motor thrust, speed settings, wind and current. Lithium holds its voltage as it discharges, so the motor keeps its speed better than it would on a fading lead-acid battery. See choosing a trolling motor battery by thrust and voltage.
24V and 36V banks
Before you build a 24V or 36V bank, check the product page and the manufacturer’s guidance on series connections. Use identical batteries, charge each one properly, and follow our guide to wiring a 24V or 36V trolling motor setup. For single-battery alternatives, see native 24V and 36V options in Trolling Motor.
House power
As a house battery, it can power cabin lights, a fridge, pumps and electronics. For overnights, estimate your daily amp-hour use with our guide to house bank sizing. Then decide whether one battery or a parallel bank makes sense. More options are in House Bank.
Group 31 swap checklist
- Measure the battery box or tray, and compare it with the listed dimensions.
- Check terminal type and position against your cable lengths and lugs.
- Secure the battery with a hold-down or tray.
- Fuse the positive lead close to the battery.
Our BCI group size guide explains why a “Group 31” label is a starting point, not a guarantee of fit.
Charging
Use a charger with a LiFePO4 or lithium profile. Built-in heating helps in cold weather, but follow the manufacturer’s charge-temperature guidance. If the battery will be charged by an engine alternator, read charging lithium on a boat about DC-DC chargers. Find chargers in Chargers.
Why heating and Bluetooth matter
LiFePO4 cells shouldn’t be charged below freezing. Internal heating lets the battery warm the cells first, which is useful for early-season trips and northern winters. Bluetooth monitoring shows state of charge at a glance, so you know when to head in or plug in.
ECO Battery FAQ
Is the ECO Battery 12V 120Ah a starting battery?
It’s sold as a deep-cycle battery. For engine starting, see Cranking or Dual Purpose.
Will it fit my Group 31 battery box?
Group 31 is its footprint, but always confirm dimensions and terminal placement.
Can I use my existing charger?
Only if it has a lithium profile. Otherwise, add a lithium charger.
Do you install ECO Battery products?
Yes, anywhere from Venice to Gainesville, FL. See local installation.
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