Ebikes use sealed lead acid batteries or SLA's not flooded as in car starters. They require the use of a three phase charger. 1st phase is full charge to approx 85 to 90% capacity. 2nd phase is the top up charge, 3rd is the maintenance charge or trickle charge. Most Chinese chargers have two led's a red and a green. In phase one the red led is lit the green is out. In phase 2 the red is lit the green will come on intermittently. In phase 3 the red is lit and the green will stay on blinking briefly as the charger maintains the voltage. When unplugged from battery pack but plugged into the ac plug the red led is lit and the green led flashes of and on quickly. This could also occur with it plugged into a bat pack with a blown fuse or a poor connection at a battery post.