So I believe the runtime is 20 mins (on normal mode) and 17 mins with a motorised head and then 8 mins on max.
Mine? It got a runtime of about 12 mins on normal mode and 5 secs on max!
Now, mine is the later model because the battery is held in by 2 screws rather than a button
Do you reckon it needs a new battery or motor unit? It has no safety switch for the filter BTW