nokia exploding batteries

How long does it take to charge Nokia BL-5C 1020mAh battery? Even Nokia doesn’t know!?

I have a new budget Nokia 1650. It comes with enhanced capacity BL-5C battery. 1020 mAh instead of the old 950mAh battery. This is the infamous battery model recalled by Nokia made by matsushita cos it can explode. What I want to know is if you have this exact 1020mAh battery, how long does it take to charge via the mini AC-3 charger?

if it is fully discharged then it takes 5 hours in switched off condition.