I Have a battery charger of 1.5 charge amp at 2 amp slow charge for a motorscooter 12v battery labeled std 1.2aX510hrs how many hrs should i charge this new battery to full capacity?

i have a scooter as well the best way for any battery charge cell phone or scooter is half charge battery when new and drain it completely half charge it again drain it once more then fully charge it and your set with scooter 12 hours should give full charge for the first