The MillerTech 24V 80Ah Sport Series is a lithium (LiFePO4) deep cycle battery built primarily for 24V trolling motors. One 24V battery replaces two 12V lead-acid or AGM batteries wired in series, so anglers running a Minn Kota, MotorGuide, or Garmin Force trolling motor can drop roughly 60 to 80 pounds off the bow while gaining a full day of steady, dependable power.
Under heavy trolling use, one battery delivers a minimum of 6 hours of continuous power. Running two batteries in parallel extends that to 12 or more hours for long tournament days. Many anglers finish a full day of fishing with a large reserve still showing on the app.
Beyond the water, the same 25.6V nominal output makes it a practical building block for 24V solar and off-grid systems, cabins, and auxiliary deep-cycle power. With 2.04 kWh of usable storage in a compact BCI Group 31 case, it fits standard battery trays and installs like a familiar marine battery.
Built-in Bluetooth lets you monitor state of charge, voltage, current, temperature, and cycle count from your phone. An integrated Battery Management System protects the cells, and a 10-year warranty backs every battery.
This model is available in two versions on this page: the Standard 2480-BT with low-temperature charging protection, and the Heated 2480-BTH, which adds a self-heating element so the battery can charge in freezing conditions. Select your version above.
Runtime
Runtime depends on your trolling motor size, speed setting, wind, and current, so treat the figures below as planning estimates rather than fixed guarantees.
MillerTech's conservative rating: one battery powers a 24V trolling motor for a minimum of 6+ hours of continuous heavy use. Two batteries in parallel run 12+ hours.
Approximate runtime from the 80Ah capacity at different average draws:
| Average draw |
Approximate runtime (single battery) |
| 10 A (low speed / spot-lock holding) |
~8 hours |
| 15 A (light to moderate use) |
~5.3 hours |
| 20 A (steady moderate use) |
~4 hours |
| 30 A (heavy use / wind and current) |
~2.7 hours |
Two batteries in parallel roughly double these times and share the load. Because this is a LiFePO4 battery, voltage stays strong through most of the discharge, so your motor keeps its speed instead of slowing as the charge drops.
Features & Benefits
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One battery replaces two: A single 24V unit takes the place of two 12V batteries in series, cutting weight and simplifying your setup.
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Lightweight Group 31 case: 40 pounds versus roughly 120 pounds for a pair of lead-acid batteries, which matters for boat performance and handling.
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Bluetooth monitoring: The MillerTech app shows state of charge, voltage, current, temperature, and cycle count, so you always know how much run time is left.
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Smart BMS protection: The built-in Battery Management System guards against over-charge, over-discharge, over-current, short circuit, and unsafe temperatures to extend battery life.
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Low-temperature charging protection: The Standard battery blocks charging below freezing to protect the cells. The Heated version self-heats from charger power so it can charge in freezing conditions.
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Sealed marine construction: IP65-rated sealed case with a stainless steel breather vent for use in wet marine environments.
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Long cycle life: LiFePO4 chemistry rated for thousands of cycles, far outlasting comparable lead-acid or AGM batteries.
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10-year warranty: Every Sport Series battery is backed for 10 years from the date of purchase.
Applications & Compatibility
This is a 24V deep cycle marine battery. It is ideally matched to 24V trolling motors of any thrust and to 24V house, electronics, and off-grid systems. It is not designed as an engine starting battery.
Recommended applications:
- 24V trolling motors, including Minn Kota (Terrova, Ultrex, Ulterra, Riptide), MotorGuide (Xi5, Tour), and Garmin Force
- Bass boats, walleye boats, catfish rigs, and bay and flats boats
- 24V marine electronics and auxiliary deep-cycle power
- 24V solar and off-grid systems, cabins, sheds, and small power banks
Wiring and expansion:
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Parallel: Up to 4 batteries for more capacity and runtime while staying at 24V. Maximum charge and discharge current scales to 120A (2), 160A (3), and 200A (4).
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Series: Up to 2 batteries to build a 48V system. Capacity stays the same and voltage doubles. Charge each battery individually with a multi-bank charger, or fully charge each individually every 10 cycles to keep the bank balanced.
Compatible chargers (24V lithium, 29.2V profile):
- 24V 10A Charger (2410C): economical AC plug-in
- 24V 15A On-Board Charger (2415M: permanent, IP65 marine
- 24V 30A Charger (2430C): faster AC charging
- 12V–24V Dark Speed On-The-Run Dual Marine Charger: charges while the motor runs
- 12V/16V/24V 3-Bank On-Board Charger (121624-3): charges multiple batteries at once
A lead-acid or AGM charger is not recommended. It cannot deliver a true full charge and may not restart charging after the battery reaches its low-voltage cutoff.
Specifications
| Specification |
Value |
| Chemistry |
Lithium Iron Phosphate (LiFePO4), Grade A prismatic cells (4P) |
| Nominal voltage |
25.6V (24V system) |
| Capacity |
80Ah |
| Energy |
2.04 kWh (2048 Wh) |
| Weight |
40 lbs |
| Dimensions |
13" x 6.75" x 9" |
| Case size |
BCI Group 31 |
| Terminals |
M8, 18-8 stainless steel (torque 10 ft-lbs) |
| Max charge voltage |
29.2V |
| Float voltage |
27.0V (not required for LiFePO4) |
| Max charge current |
80A (15A recommended) |
| Charge temperature range |
Standard : 32°F to 125°F.
Heated: self-heating enables charging below freezing |
| Max continuous discharge current |
80A |
| Peak discharge current |
240A for 5 seconds |
| Operating / discharge temperature |
-4°F to 125°F |
| Discharge cut-off voltage |
20V (any cell 2.5V) |
| Recommended low-voltage disconnect |
24V |
| Efficiency |
98% |
| Cycle life (to 80% capacity) |
2,000 at 100% DoD; 3,800 at 80%; 5,000 at 50%; 8,000 at 30% |
| Heating |
Standard: none.
Heated: built-in self-heating element |
| Low-temperature charging |
Standard: charging protection cuts off near 30°F and reconnects at 32°F, so the battery does not charge
below freezing.
Heated: self-heats near 32°F to allow charging in freezing conditions (heater runs only while the charger is connected) |
| Battery Management System |
Yes |
| Bluetooth monitoring |
Yes (MillerTech app) |
| Communication / data |
Bluetooth app monitoring only (no CAN bus communication) |
| Enclosure rating |
IP65 sealed, stainless breather vent |
| Certification |
ANSI/CAN/UL 1973:2022 Ed.3 |
| Series / parallel |
Series up to 2 (48V); parallel up to 4 |
| Warranty |
10 years |
FAQs
Does one 24V battery replace my two 12V trolling motor batteries?
Yes. One MillerTech 24V 80Ah replaces two 12V lead-acid or AGM batteries that were wired in series to make 24 volts. You connect the single battery to your existing 24V trolling motor leads.
How long will it run my 24V trolling motor?
One battery runs a minimum of 6 hours under continuous heavy use, and two in parallel run 12 or more hours. Actual runtime varies with motor size, speed, wind, and current. Lighter use and spot-lock holding typically stretch a single battery across a full day.
What charger do I need?
Use a 24V lithium charger set to a 29.2V charging profile, such as the MillerTech 2410C, 2415M, 2430C, the 12V–24V Dark Speed dual charger, or the 121624-3 multi-bank charger. A lead-acid or AGM charger cannot fully charge the battery and may not restart after a low-voltage cutoff.
Can I wire two batteries in parallel?
Yes. Up to 4 batteries can be connected in parallel to increase capacity and runtime while staying at 24V. Use appropriately rated cables, fuses, or breakers, and make sure battery voltages are close before connecting.
Can I wire two in series for a 48V system?
Yes. Up to 2 batteries can be wired in series for 48V. Voltage doubles and capacity stays the same. For best results, charge each battery individually with a multi-bank charger, or fully charge each one individually every 10 cycles.
Will it fit my battery tray?
The battery uses a standard BCI Group 31 case measuring 13" x 6.75" x 9" and weighs 40 pounds. It fits trays and compartments designed for the Group 31 footprint. Terminals are M8 stainless bolts.
Can I charge it in freezing weather?
The Standard 2480-BT has low-temperature charging protection that blocks charging below freezing to protect the cells. The Heated 2480-BTH adds a self-heating element that uses charger power to warm the cells so it can charge in freezing conditions. The heater only runs while a charger is connected.
Can I use it in a 24V solar or off-grid system?
Yes. The 25.6V nominal output works in 24V solar and off-grid setups. Pair it with a 24V charge controller and inverter, and keep loads within the 80A continuous discharge rating.
Is this a starting or cranking battery?
No. It is a 24V deep cycle marine battery intended for trolling motors, electronics, and deep-cycle loads, not for starting an engine.
What does the Bluetooth app show?
The MillerTech app displays state of charge, voltage, current, temperature, and cycle count. You can monitor more than one battery from the same app.
How long will the battery last?
Cycle life to 80% remaining capacity ranges from about 2,000 cycles at full 100% depth of discharge up to about 8,000 cycles at 30% depth of discharge. The battery is backed by a 10-year warranty.
Does it need maintenance?
Very little. For storage, charge to at least 50% and top off every three months. Parallel banks self-balance through the BMS. Series banks should have each battery fully charged individually every 10 cycles.
Is it waterproof?
The case is IP65 sealed and water resistant for marine use. It should not be submerged or used in direct spray or standing water.
What is the difference between the Standard and Heated versions?
The Heated version adds a self-heating element that lets the battery charge in freezing conditions. Capacity, voltage, discharge specs, and dimensions are the same for both versions.
How do I install and torque the terminals?
Connect to the marked positive and negative terminals, and never reverse polarity. Tighten the M8 stainless bolts to 10 ft-lbs with a torque wrench. Loose connections can overheat and damage the battery.
