What are some early warning signs that a battery might be going bad? I currently have 4 batteries. The original battery that came with my bird seems to have a slight (very slight, but is enough to notice when you feel across the top flat portion and compare to my newer batteries) amount of bulging. I have only flown with it maybe 10 times and I have only had the copter for about 3 months. I also try to follow the charging guidelines very closely. This may be normal for these batteries, but I would hate to ignore an early warning sign and find out when my bird falls from the air.