I have two of these pagers, one for each of my bikes.
When they are charging, one shows a blinking red light, while the other shows a solid red light. This happens regardless of how long they remain on charge.
That's normal, it's a power saving feature of the pager. The device is still functioning fine, it just shuts off the range confirmation LED after an hour.
Thanks for this info. How do you know when you're out of range?