12V 55AH Sport Series Lithium Battery w/ Bluetooth (1255-BT)

(3 Reviews)
$399.00

Free shipping

Applications For This Battery

Built in low-temp charging protection!

Download ManualDownload Sports Series WarrantyApple StoreGoogle Playstore

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Capacity
55AH
Voltage
12.8V
Weight
17.1 lbs
Size
9” x 5.5” x 8.5”
Warranty
10 years

BMS: Yes
Chemistry: LFP
Efficiency: 98%
Memory: None
Max Charge/Voltage: 14.6V
Peak Discharge: 180A
Cut-off Voltage: 10V
Max Charge/Discharge Current: 55A
Operating Temp: 32°F – 130°F
Low Temp Charging Protection: Yes
Cell Type: Prismatic
Bluetooth: Yes

Simple 10 Year Warranty
From the date of your battery purchase through year number 10 of ownership, your battery is covered. If it stops working during this time, we will repair or replace it with a battery of equal or greater value for FREE!

The Sport Series Marine Batteries

The Sport Series Marine batteries are all sealed with a thick rubber gasket along the lid connection point. This means they are Marine approved IP65 rated. A completely sealed battery case will cause condensation, so we build them with a marine grade Stainless Steel breather vent. Our vent sits on the top of the case unlike some others where the vent sits down inside catching rain and dirt.

Custom molded, heavy duty, re-closable battery case. This means if you ever have an issue with your battery no matter is it in year 5 or year 15 we will always have easy access to repair any defective parts. This custom case also has convenient hold down strap grooves molded into the side corners helping to keep your straps seated securely in place.

Recommended Charger
The Millertech 12V 55Ah lithium battery is engineered for a 14.6V charging profile.  For maximum performance, battery health, and a true 100% charge, the Millertech 12V 10A Lithium Battery Charger (1210C) is strongly recommended.

Capacity – 55Ah

This battery has a storage capacity of 55 amp-hours (Ah). That means it can power larger accessories or run equipment for extended periods between charges.

Voltage – 12.8V

The battery operates at a nominal voltage of 12.8 volts. This allows it to directly replace traditional 12V lead-acid batteries while delivering more stable and consistent output.

Weight – 17.1 lbs

The battery weighs 17.1 pounds. It is significantly lighter than a comparable lead-acid battery of the same capacity, making installation easier and reducing overall system weight.

Size – 9” × 5.5” × 8.5”

The battery measures 9 inches by 5.5 inches by 8.5 inches. Its compact design allows it to fit into many standard battery compartments with minimal modification.

Battery Management System (BMS)

The battery includes an integrated Battery Management System (BMS). The BMS protects against over-charging, over-discharging, excessive current, and unsafe temperatures to extend battery life.

Efficiency – 98%

The battery operates at 98% energy efficiency. This means nearly all stored energy is usable, resulting in longer run-times and faster charging.

Memory Effect

This battery has no memory effect. You can charge it at any state of charge without reducing overall capacity over time.

Max Charge Voltage – 14.6V

The maximum charging voltage for this battery is 14.6 volts. Charging within this range ensures a full charge while protecting internal cells.

Peak Discharge – 180A (3 Seconds)

The battery can deliver up to 180 amps for short bursts. This allows it to handle high-demand startup loads such as motors or surge-heavy electronics.

Cut-Off Voltage – 10V

The battery has a low-voltage cut-off at 10 volts. This protects the battery from over-discharge, helping extend overall lifespan.

Max Charge / Discharge Current – 55A

The battery supports up to 55 amps of continuous charge and discharge current. This defines the safe operating range for sustained power draw and charging input.

Operating Temperature – -4°F to 140°F

The battery is designed to operate in temperatures ranging from -4°F to 140°F. This wide temperature range makes it suitable for both cold and hot environments.

Low-Temperature Charging Protection 

The battery includes built-in low-temperature charging protection. This prevents charging in freezing conditions, helping protect the cells from damage.

Cell Type – Prismatic

This battery is constructed using prismatic lithium cells. Prismatic cells allow for higher capacity in a compact footprint and efficient internal packaging.

Terminals
Built with heavy-duty M8 stainless steel terminals for powerful performance without excessive heat.

Built-In Bluetooth
Equipped with Bluetooth technology. The battery connects to an app that allows you to conveniently monitor multiple batteries at once—no more checking multiple apps. You can download the app here

Robust Design  for Longer Life
Robust yet lightweight, Millertech Sport Series Lithium Batteries can last up to 10X longer than AGM or lead-acid batteries. Never be stranded with a dead battery again!

THE MILLERTECH® SPORT SERIES LITHIUM BATTERY
10 YEAR GUARANTEED WARRANTY IS SIMPLE!

TERMS:

From the date of your battery purchase through year number 10 of ownership, your battery is covered. If it stops working during this time, we will repair or replace it with a battery of equal or greater value for FREE!

SHIPPING:

We cover all shipping costs associated with shuttling your battery back and forth for repair or replacement. It is our warranty; it is our cost; not yours.

EXCLUSIONS:

There are NONE! You trusted Millertech®, and if it’s within the warranty period your Millertech® battery is completely covered for everything!

PROOF OF PURCHASE:

You don’t need one. If it’s Millertech®, it’s covered!

FOR WARRANTY SERVICE CALL: 855-MAX-LITH
EMAIL:  warranty@millertechenergy.com

Customer Reviews

Maurice Tetreault
Rating: 5/5
New to Millertech
Batteries and charger work great. Love the bluetooth and App to let me know level of charge.
Sun Mar 23 2025 21:50:45 GMT+0000 (Coordinated Universal Time)
D. Barber
Rating: 5/5
Great Service, Great Batteries!
Batteries came very quick and packaged very well. Hooked them up, and went out to try them out. I have a 17ft tracker, and after about two to three hours of running around with my 24V trolling motor, I still had 95% capacity on my batteries. Being able to see the capacity and what the batteries are doing in real time on the App, is great. Thanks MillerTech!
Sat Mar 22 2025 15:04:20 GMT+0000 (Coordinated Universal Time)
Rodney Spencer
Rating: 5/5
55ah battery
I bought a Millertech 55ah to run my electronics. My first impression is the Bluetooth data that the battery shows. I read a lot of reviews on many companies batterie's, but I came back to these principals. American made and here in Ohio. The company techs have great knowledge on the products they sell.
Sun Jan 12 2025 01:13:30 GMT+0000 (Coordinated Universal Time)

What the pros are saying about Millertech batteries