I've been testing this evening with my Anker 20100mAh unit...I chose this as it's the smallest and lightest for the capacity (about 350 grammes), has auto switch off and has good reviews. It's a reputable make who I've bought from before and had great customer service (when something didn't work with something which they said did and it didn't, and they didn't realise, they refunded my money AND let me keep the unit. So I bought this partly to show my appreciation even though a similar one of another make is cheaper - but larger and heavier).
http://www.amazon.co.uk/gp/product/B00VJSGT2A?keywords=anker&qid=1447030019&ref_=sr_1_1&sr=8-1Anyway, I've been measuring the voltage between pins 2 and 6. I started doing this then a friend messaged me to see if I wanted to go and meet him for dinner in Epsom, so there's a bit of a jump...but as you'll see that doesn't really matter.
13:40 4.95V - start of the test.
14:40 4.95V - after 1 hour
15:40 4.95V - after 2 hours
16:40 4.95V - after 3 hours
This is where I abandoned the test until I got home....
00:40 4.95V - after 11 hours
The test is being done with the PAW having the Wifi on, the ADS-B dongle on, and the USB Ublox GPS on, and it has the ARF in it, transmitting every 2 seconds. At the moment it seems that after 11 hours, it's still giving the same voltage as when I started the test.
I'm going to go to bed soon, and I'll leave it on, see if it's still on in another 7 hours!