Milwaukee M12 RedLithium High Output Batteries

In 2018, Milwaukee released the M18 RedLithium High Output batteries, which supported their M18 tool platform with much higher available power. Now, Milwaukee has announced that their M12 batteries will also join the RedLithium High Output lineup, designed to deliver more power and better performance for the M12 tools. Is it time to give your tool arsenal a battery upgrade? You be the judge.

Two M12 battery packs were given the RedLithium High Output branding: the CP2.5 (48-11-2425) and the XC5.0 (48-11-2450) batteries. Milwaukee tells us that they provide 25% more power on high-demand tools. In fact, they were designed to deliver on lithium-ion's fade-free power promise in heavier draw applications.

The M12 Redlithium High Output batteries provide increased performance while maintaining the same footprint as the current M12 RedLithium CP and XC battery models. Improved thermal technology also helps to keep the battery packs up to 25% cooler to avoid overheating. Heat is one of the biggest challenges to allowing batteries to provide more current, so that level of thermal control is a really big deal.

Another aspect Milwaukee improved upon was the batteries’ durability. The updated M12 RedLithium High Output batteries were designed to withstand wear, and as a result, they are resistant to oils, solvents, and greases commonly found on the job.

We got a chance to use these new batteries in the updated 3rd-Gen Milwaukee M12 Fuel impact driver. In a head-to-head against their former batteries, the new models squeezed out a little more power and speed. If I had to guess, I’d say around 5-10%. We look forward to doing more testing once we have the new batteries in-house.

Another thing we noticed, however—Milwaukee improved the connection point. The new batteries seem to attach and detach with a more secure feel than the old batteries. The new mechanism feels more reliable. We also need to test that out, but it looks like an improvement.

Overall, since you can't jam thicker 21700 cells into the space afforded by an in-handle M12 battery—nor would you want to—this looks like a great incremental improvement for the line.

The CP2.5 RedLithium High Output battery pack (48-11-2425) retails for $79 including a 2-year warranty. The XC5.0 RedLithium High Output battery pack (48-11-2450) goes for $119 and includes a 3-year warranty. Both battery packs are set to launch in August 2022.