My inbox is often filled with press releases about the latest RC hobby products. I try to focus my attention on the truly unique and innovative stuff. That's why the ARRMA Granite Voltage ($140) caught my eye. On the surface, it appears to be a run-of-the-mill 1/10-scale monster truck. But this is no ordinary backyard basher. The Granite Voltage is equipped to use a power source that I've never before seen in an RC truck, cylindrical Lithium-Ion (Li-Ion) batteries. I'm a battery nerd, so I had to take a closer look.
The 18650-sized (18mm diameter, 65mm long) Li-Ion batteries used by the Granite Voltage are not new. Derivatives of these cells have been around for more than 20 years. They've always been a popular choice for small electronic devices because of their high energy density, convenient size, and robust housing. However, these cells never really captured the interest of RC hobbyists. The issue was that Li-Ion cells couldn't discharge rapidly enough to meet the high-current demands of most RC vehicles. Simply put, Li-Ion batteries were great at storing energy, but not so great at expending that energy quickly. Most hobbyists adopted a different flavor of Lithium-Ion technology with more favorable discharge characteristics, the soft, flat Lithium-Polymer (LiPo) cells that now dominate RC applications.
Recent developments with cylindrical Li-Ion batteries have finally made them contenders for hobbyists. The latest generation of 18650 cells have high discharge capabilities, giving backyard drivers another battery option. I also found it interesting that Tesla and the vaping community have also embraced the allure of modern 18650 Li-Ion batteries.