Review of the Milwaukee M18 Lithium Ion 9.0 Ah Battery

I love me some battery powered tools! With the technology in batteries and high efficiency brushless motors constantly moving forward, the old days of having to sacrifice the good power of a corded tool for the convenience and flexibility of cordless tools are effectively over. Today I’m going to lower the lens down on a recently released battery from Milwaukee: The M18 Lithium-Ion 9.0 Ah High Demand Battery. Short story – This thing is a BEAST.

If you’re already invested in the Milwaukee M18 line then I don’t have to convince you of their good quality and construction. The lower capacity batteries perform very well with these products and, while their battery efficiency is above average, this 9.0 Ah battery is just off the charts.

Let’s side step aside and define this squirrelly unit real quick – What does “Ah” stand for anyhow? “Ah” is an abbreviation for “Amp-hour” and, as you might guess, quantifies the capacity of a battery. A ‘1 Ah’ battery is theoretically capable of delivering 1 amp of electrical current for 1 hour of time. However, this does not mean that when a load is connected to something like our 9.0 Ah battery, that the battery will be dishing out 9 amps of current. That would be pretty nutty : )

Milwaukee uses a pretty snazzy battery management system that varies the output current of the battery depending on the load placed on the battery. Because of internal battery impedance (or resistance), batteries tend to get very hot while using them. Generally, this is exactly why our theoretical battery cannot exactly deliver that 1 amp for 1 hour like we mentioned above. This battery has been developed with a smart lay-out of the cells and thermally efficient materials to move the heat in a way that keeps the entire pack much cooler than one would expect.

So what about the performance? I am mainly using this battery for my Milwaukee M18 Miter Saw. I offered up a review for it a while back and it can be found here. This battery works so damn good I tend to forget that my miter saw is battery powered because the charges last so long. I’d love to offer you things like “number of cuts per charge” but I simply have not collected that data because the battery has only required a two charges since I unboxed the saw and I’ve made hundred of cuts with it.

Milwaukee reports that the battery delivers 5 times more run time, 35% more power, and runs 60% cooler than standard 18V batteries on the market. After looking around at what others are saying online it’s easy to see that professionals are getting more cuts, drilling more holes, and driving more fasteners than ever before on a single charge using this 9.0 Ah pack.

The battery is a bit pricey but well worth the investment, especially if you’re buying it as a bundle with the rapid charger. When you consider the amount of time you’ll be saving by having the larger capacity, it shouldn’t take too long to see it’s well worth the money.

If you’re interested in buying one of these batteries, feel free to use this link. This link, along with some of the others are affiliate links established under The Home Depot ProSpective Campaign which has sponsored this post as well as some others. Purchases made using these links help this page to stay alive and kicking.  I appreciate your support in this way.

Have a great day – April : )