10-15 minutes maybe (cant remember the actual time) it was use on low for a bit before i put it up, but i do remember thinking 'already?' as it stopped
I will be ordering the 8ah battery kit very, very shortly.
Probably closer to 10 than 15 minutes continuous run time... at least the 5's charge faster than the 8's. I haven't checked recently but the euro per ah was cheaper on the 5's than the 8's, add in the faster charge time and it swung it for me.