You are the second person to describe the “disconnect from Android for more than an hour, find meter unconnectable” issue, so now I have something to look for.
I have another suspicion – when the meter is in the unconnectable state, does it appear in scans from another device? How about if you turn off the Android phone you originally used to connect to it?
My suspicion is that Android is doing something stupid… one of the features of the Android BLE API is that you can tell it to try to connect to a peripheral in the background. The Mooshimeter app doesn’t use this feature, but my suspicion is that Android is connecting in the background as soon as your phone is in range of the meter, then Android is not handing the connection to the app, so it doesn’t appear in the scans. Just a hunch, but all bug-hunts start with a hunch.