The Nokia charger is 5V@550mAh
The Blackberry charger is 5V@750mAh
I noticed with the OEM charger that came with the phone my battery drained at 2% every 30 minutes. Now I see where I left the phone alone for more than 30 minutes today and that 30 minutes of sitting idle drained the battery 1%.
I hope that turns out to be a pattern.