Frist of all what do you mean by drain the battery?If that is what you are doing you have a battery problem. Seeing it a new battery its a good chance the battery its self isn't bad but not 100%. You say it fully charged but what is telling you this. Are you taking a hydrometer test? What is the battery voltage after its drained? If you still have good voltage after its drained start checking for bad connections or a bad starter.
I have a 10 amp charger. When the battery is charged the guage on the reads 0. When it is not charged it reads 6 or higher. As it charges the needle falls from 6 or more to 0. No. I do not have that meter. Thanks