I've had this for 2 months, and I bought two more after the first one. Testing it with DC bulbs I found it to have about 140 watt hours of capacity, a little less than the 166 spec. Using the built in A/C converter uses up about 10% more so you'll get about 125 watt hours. 

DrSmile

I just wish we discovered this cordless years ago before we spent wasted money on the Dyson!

Warren Estes

This vacuum is so versatile. I use it instead of my bulky corded vacuum for our carpets, and it's easy to switch over to use it without the extension and use it to clean up small messes.

Jeremy Clarkson