Milwaukee M18™ HIGH OUTPUT™ 5.5Ah Battery (M18 HB5.5)

Milwaukee M18™ HIGH OUTPUT™ 5.5Ah Battery (M18 HB5.5)

When tools are pushed hard and workloads don’t slow down, the battery powering them has to deliver more than just capacity — it has to maintain performance under pressure. The Milwaukee M18™ HIGH OUTPUT™ 5.5Ah Battery is designed for professionals who rely on sustained power, longer runtime, and consistent output in demanding applications.

Built using HIGH OUTPUT™ REDLITHIUM™ technology, this advanced battery delivers up to 50% more power than standard M18™ REDLITHIUM™ batteries. It is engineered to drive high-demand tools such as grinders, circular saws, SDS drills, and outdoor equipment, helping achieve true corded-level performance while retaining the flexibility and convenience of cordless operation.

A major advantage of the M18 HB5.5 is its ability to run up to 50% cooler during heavy applications. Reduced heat build-up allows tools to operate at higher output for longer periods, improving performance consistency and helping extend the overall service life of the battery. This makes it particularly well suited to continuous cutting, grinding, drilling, and extended site work where downtime is not an option.

At the core of the battery is REDLINK™ Intelligence, Milwaukee’s advanced electronic protection system. It continuously monitors temperature, voltage, and current to protect against overload, overheating, and over-discharge. Individual cell monitoring ensures balanced charging and discharging across all cells, maximising efficiency and long-term durability.

Designed for real jobsite conditions, the M18 HB5.5 features a durable metal frame construction with shock-responsive separators. This robust design helps protect internal components from damage caused by drops, vibrations, and everyday site use. An on-board fuel gauge provides a clear indication of remaining charge, allowing better planning and improved productivity throughout the working day.

Fully compatible with the Milwaukee M18™ system, this HIGH OUTPUT™ 5.5Ah battery offers an ideal balance between power and runtime. It is a natural upgrade for users who require longer operating time than smaller HIGH OUTPUT™ batteries, while maintaining control and balance without unnecessary bulk.

Key Features & Benefits

• HIGH OUTPUT™ REDLITHIUM™ technology delivering up to 50% more power

• 5.5Ah capacity for extended runtime

• Runs up to 50% cooler under heavy load

• REDLINK™ Intelligence protects against overload, overheating, and over-discharge

• Individual cell monitoring for improved battery life

• Durable metal frame construction with shock-responsive separators

• On-board fuel gauge for efficient runtime management

• Compatible with the full Milwaukee M18™ cordless system

Ideal For

• High-demand M18™ cordless tools

• Cutting, grinding, drilling, and continuous site work

• Professionals requiring extended runtime and sustained power

• Users upgrading from standard M18™ REDLITHIUM™ batteries

What’s Included

• 1 × Milwaukee M18™ HIGH OUTPUT™ 5.5Ah Battery (M18 HB5.5)