he said 40 years worth of use for the battery, so if a battery on these is used on average 10hrs a year (high season only, as an example), then he's saying he has put his battery through 400 or so hours of use, which amounts to approx. 17 days. This is a common test for consumert appliances, calculate the average runtime, and run it 10x longer to test resiliency. Besides, these batteries are interchangeable between weedwackers, lawnmowers, snowblowers, etc... so I can see how one would get through a lot of hours on one.
