What Battery Beast is Best? Milwaukee HIGH OUTPUT vs. FORGE

Published June 11, 2025

Milwaukee’s M18 battery lineup includes some of the most advanced cordless tool batteries on the market. Two standout 6.0Ah models—the Milwaukee M18 REDLITHIUM HIGH OUTPUT 6.0 (48-11-1865) and the next-generation M18 REDLITHIUM FORGE 6.0 (48-11-1861)—are both optimized for power-hungry tools, but they take different approaches. We’ll compare their internal tech, charging capabilities, thermal management, and performance under load so you can decide which is right for your workflow.

Comparison Table

Feature	M18 HO 6.0 (48-11-1865)	M18 FORGE 6.0 (48-11-1861)
Battery Type	REDLITHIUM HIGH OUTPUT	REDLITHIUM FORGE
Amp-Hours (Ah)	6.0Ah	6.0Ah
Voltage	18V	18V
Battery Cells	21700 cells	21700 cells (next-gen configuration)
Max Power Output	Up to 50% more power vs. standard packs	Even higher output than HO under sustained load
Cooling Technology	Upgraded heat management	COOL-CYCLE active cooling system
Charge Speed	Fast with standard rapid charger	Up to 2x faster with Super Charger
Weight	~2.5 lbs	~2.4 lbs
Tool Compatibility	All M18 tools	All M18 tools (ideal for peak draw tools)
Best Use Case	High-demand saws, grinders, hammers	Fast charging, high-power, and low-heat jobs

Milwaukee M18 REDLITHIUM HIGH OUTPUT 6.0 Battery (48-11-1865)

The HO 6.0 battery was a major upgrade from the older XC series, introducing 21700 cells for better energy density and increased power delivery. It delivers up to 50% more power than previous REDLITHIUM packs and runs significantly cooler under heavy loads, thanks to upgraded cell layout and heat dispersion.

It’s a go-to for trades that rely on mid- to high-demand tools, offering excellent performance and runtime without the need for proprietary chargers. If you’re using tools like M18 FUEL grinders, circular saws, or impact wrenches, this pack will help those tools run at full capacity.

Alternate Names:

• Milwaukee 48-11-1865
• HO 6.0 M18 Battery
• M18 High Output 6Ah Pack

Milwaukee M18 REDLITHIUM FORGE 6.0 Battery (48-11-1861)

The FORGE 6.0 battery takes everything the HO 6.0 offers and turns it up a notch. It still uses 21700 cells but with an optimized arrangement and additional enhancements, including the COOL-CYCLE active cooling system and Super Charger compatibility. It not only stays cooler under extreme loads but also recharges up to twice as fast when paired with Milwaukee’s latest charger tech.

FORGE is engineered for the most demanding users—those who need the absolute highest sustained output with minimal downtime. It’s ideal for pro users running SDS-Max hammers, large circular saws, or back-to-back high-load cuts.

Alternate Names:

• Milwaukee 48-11-1861
• FORGE 6.0 M18 Battery
• M18 Fast-Charge High Performance Battery

---

Key Differences Between High-Output and FORGE Batteries

• Cooling Systems: Both have upgraded thermal designs, but FORGE introduces active COOL-CYCLE cooling.
• Charging Time: FORGE charges up to 2x faster with a Super Charger; HO charges quickly but less so.
• Performance Under Load: FORGE maintains voltage better in sustained high-draw applications.
• Compatibility: Both work with all M18 tools; FORGE is ideal for continuous-use, high-load workflows.

---

Conclusion

The HIGH OUTPUT 6.0 (48-11-1865) is still a powerhouse battery, perfect for most heavy-duty tasks. It gives you fast discharge, good runtime, and compatibility with the full M18 ecosystem—without needing a specialized charger.

But if speed and heat are critical to your workflow, the FORGE 6.0 (48-11-1861) pulls ahead with rapid charging and advanced thermal controls. You’ll keep tools running stronger for longer—and get back to work faster.

Whether you’re upgrading your battery fleet or investing in new gear, understanding these differences helps you build a setup that fits your performance needs and your pace.

Posts on Slice Hardware are for information purposes only and not advice for projects, tool use, or safety.