Usually it is not necessary to use a high amp charger as the charging circuit in the watch will never allow high currents anyway. If the battery is in deep discharge then a state of the art charging circuit will trickle charge it until it can come back to a normal charge. This is why it can take a long time on the charger until he device comes back to life. Thus the recommendation for deep discharged devices is: leave it on the charger for a longer time. I would only call it defective if it does not come back after a day or so. This does not solve the initial high discharge though…