As perhaps the leading manufacturer in cordless power tools, Milwaukee has done an impressive job stretching their 18-volt platform to include some tools we never thought were possible. For instance, some of the newer products such as the miter saw, table saw, and just about all their outdoor power equipment are tools that most other manufacturers wouldn’t dare risk putting on their 18-volt or 20-volt platforms. Milwaukee, however, seems to be sticking with the M18 system, leading the industry in cordless technology without upping the voltage. To make this happen, Milwaukee needed a battery that could handle their vision of a cordless 18-volt world. This is why they designed the topic of today’s post: Milwaukee’s M18 Redlithium 12.0HD Battery Pack.
I want to start right now by saying that I am very impressed with this battery. I initially had some doubt as to whether this battery is worth the jump from the 9Ah, but I quickly realized that this battery is unmatched. Some things that Milwaukee notes on their website are that this battery pack has 50% more power, runs 50% cooler, and delivers 33% more run-time. These things are great, but if you think anything like me, these mean nothing unless they can be backed up by some sort of evidence. So, I watched and read all the videos and reviews I could find, and the battery seemed to outperform all its counterparts by a significant margin. Still, if you aren’t as convinced by Youtube tool reviews as I am, let’s look at the science.
Lithium-ion batteries have been a crucial advancement in cordless technology, mainly because they are rechargeable, light, and extremely efficient, but where does it proceed from there? Maybe you change the chemical structure or use more conductive materials, but the most critical change Milwaukee made with the cells of this battery is the shape. Instead of using the standard 18650 cells, Milwaukee switched to 21700 cells (These numbers only refer to the dimensions of the cell, i.e., 21700 means the cell is 21mm in diameter and 70mm in height). This greatly improves the performance of the pack in several ways. Let’s discuss what I believe the two most important: power and run-time.
It turns out Milwaukee isn’t joking about the battery having more power. To put it simply, by increasing the size of the cells, the energy content can potentially be increased by approximately 50%. So, this means you get the same energy for a smaller number of cells. Milwaukee’s 9Ah HD battery uses 15 18650 cells. Instead of adding more to get to 12Ah, Milwaukee just put in 15 21700 cells. With the same number of cells, each of which is capable of having an energy capacity 50% higher, the battery boasts a significant power increase.
Longer run-time is maybe the most glaring obstacle for cordless tool manufacturers today. Even if you can match corded power, people won’t buy your tools if it can only complete half of what they need it to. So, you increase the run-time. Simple, right? Obviously upping the Ah will give you more run-time, but Milwaukee wanted to take it a step further. To maximize the run-time you get out of a battery, you have to minimize the heat dissipation. The secret to accomplishing this lies within the density of the cells. The more dense or thick the electrodes are, the more energy you can fit in them. The trade off is that with thicker electrodes, there is a higher internal resistance (resistance to the current of electrons). Without getting too complicated, internal resistance will cause a current to expend energy on whatever is resisting it, this energy is released in the form of heat, and the loss of energy lowers the voltage. The 21700 allows the battery to fit the power necessary for 12.0Ah over a larger surface area. So, for each cell you have the required power capacity and low internal resistance. This means not only are you getting 12.0Ah of run-time, but you are getting a cooler operation that allows the battery to perform better.
Milwaukee’s M18 Redlithium 12.0HD Battery is the most advanced battery from Milwaukee. I highly recommend having one on hand, especially if you own or are planning to own any of Milwaukee’s larger M18 FUEL tools. Finally, we have a battery that will deliver the power and run-time to do more with our M18 tools. It weighs in around 3.6 lbs. so it might not be ideal for smaller tools, but hey if you want to put this thing on your impact driver, go for it. That’s the beauty of the M18 system, and it just got a lot better with this battery.
For more information on this tool visit our site here.