DH got a "starter set" of DeWalt tools (drill, driver, flashlight, and 2 batteries) as a gift. Then he got a DeWalt chainsaw, which needs a larger battery. For our 30th anniversary, he got me a DeWalt string trimmer that uses the same battery as his chainsaw, so it was a gift for himself too.
I just asked how long he can run the chainsaw with those two batteries, and he estimated an hour and a half. I know I can do a LOT of string trimming with two batteries. I'd guess they take 2 hours(?) to charge.
He's looking at some other DeWalt tools to add to the line up. I said fine, if I get to play with them too. And I hope they take the bigger battery.
You can put the big battery on the small tools; they're just heavier to use and carry. I sure do like being about to take the drill and driver out to the coop to do stuff.