[legion]

In my experience, a battery-powered equivalent of a gas-powered tool will drain the battery in 10-20 minutes of continuous use.

If you have one battery, you can get 10-20 minutes worth of work done before being forced into a 2-hour break.

If you have two batteries, you can get 20-40 minutes worth of work done before taking a 1 hour, 40 minute break to 1 hour, 50 minute break.

If your tool drains the battery in 20 minutes, you need a minimum of 6 batteries to be able to work continuously. If your tool drains the battery in 10, you need a minimum of 12 batteries to be able to work continuously. Now go price 5-11 spare batteries, and tell me which type of tool is cheaper...