My bruno stair lift is having issues and I'm trying to determine what the problem is. The battery appears to be mostly dead and not charging even though it's at the end of the rail (where it would normally charge). It keeps beeping 3 short and 2 long beeps and it does it about every 5 minutes. Under the seat, the little display thing shows L8 solid then C1 solid and then C4 flashing. Anyone have experience with this? I was thinking it would just be a battery problem (it's about 6 years old), but wanted to see if anyone here would have any other ideas.