One of the great innovations for the construction industry is the “all-day” battery-powered tool. These typically operate at 24VDC, but that doesn’t mean there aren’t any safety issues.
Take the cordless drill for example. When that battery gets low after, say, sawing holes all morning, the drill will turn more slowly. Cutting ability depends not only on the sharpness of the hole saw, but also on the speed of the drill. As cutting ability decreases, the likelihood of slippage and injury increases.
The solution? Use an AC-powered drill and portable cord. Or, have a second drill or spare battery charged and ready to go. And don't forget to replace worn hole saws and drills.