The Milwaukee Electric Tool Corporation produced two generations of 18-volt cordless power tools based on rechargeable lithium-ion batteries. The first was named V18, and was compatible with earlier battery systems. The M18 series represented a complete break with the earlier series, redesigned and using a new battery system.
In 2006, Milwaukee announced a new battery system trademarked as V18, with a rechargeable lithium-ion battery, to replace the nickel-cadmium rechargeable batteries used previously. The company marketed the V18 system as an upgrade to its existing cordless power tools, promising a 50 percent longer run time than nickel-cadmium batteries. As the company stated in a press release when it announced the new V18 system, “By placing a V18 battery on their current 18-volt tools, tradesmen are able to get an immediate performance boost without investing in an entirely new platform.”
In 2007, Milwaukee introduced the 2601-22 cordless drill, touting it as powerful but lightweight and compact, weighing 4 pounds. The battery pack was indeed half the weight of the earlier lithium-ion battery, and produced half the power. Despite the lightweight, 18-volt battery’s similar "18v" labeling, however, it wasn't compatible with the tools sold with the larger V18 lithium-ion pack.
In 2008, Milwaukee introduced the 2610-24 drill as the marquee tool in the new M18 series. The M18 series tools were no longer backwards compatible with the older nickel-cadmium systems, allowing the tools themselves to be redesigned and balanced with strictly lithium-ion power packs. Notably, the M18 series came with a frameless motor that could produce the same amount of power as a larger, traditional electric motor. The company labeled the lithium-ion battery system used in the M series as "18V XC High Capacity."
In 2010, Milwaukee moved to RED LITHIUM batteries for the M18 and M12 series of tools. The Milwaukee Company marketed this new line of batteries as an immediate upgrade in the performance of its tools, much as it did when it first introduced lithium-ion batteries as a replacement for nickel-cadmium batteries. In a September 2010 press release on its website, the company claimed the new line of batteries -- compatible with all M12 and M18 tools being sold at the time -- provided up 20 percent more power and 50 percent more recharges than conventional lithium-Ion batteries.