This top Gardena model shrubber has two 3.6v lithium-ion batteries which gives it a long running time. I've used it for 2.5 hours without recharging. Not even showing a yellow light warning of half charge. Unfortunately, that 2.5 hours included about 1/2 time not running because I had to use my manual hedge shears for about 1/2 my shrubs. It is simply ineffective for dense, internally moist and/or woody shrubs. Still, I found it useful to give my arms and back a rest from using the shears throughout. As other reviewers of other shrubbers have pointed out, you need to determine on what shrubs such a device is effective, and limit its use to them. Incidentally, the lithium-ion Gardena cuts about the same as my old NiCd Black and Decker at half the price or so, but much less running time. I also own electric-corded and gas powered hedge trimmers. I prefer the combination of the Gardena and manual shears.