That issue seems to be directly addressed in the other battery-powered model–the $129.00 18V One+ HP Brushless 4 ½-inch Angle Grinder.Brushless motors generate less heat via internal friction ...

The energy difference is offset to a large degree by the difference in blade diameter, but a grinder with a saw blade is more dangerous than a circular saw. Let’s first address blade safety. All of ...

Most of their cordless grinders are powered by a 20-volt battery system, which provides long-lasting power. Alternatively, the 60-volt MAX is a heavy-duty option offering 2,300 watts of power ...

Ryobi sells a couple of battery-powered grinders as well. They're offered in kits or as solo tools with slightly different designations, but these essentially boil down to two models.