I have Ultegra di2 on my cross bike. It's about a year old and previously worked fine. I haven't ridden it since cross season and when I checked the battery it was dead. I charged it and it went dead in about 2 days. I charged it again and when I checked the status the green light came on and then the green and red lights came on together. It went dead again in 2 days. I did update the firmware. I don't have the diagnostic box and live in the sticks so my local bike shop is not familiar with di2. Can anybody help?