When you get ready to restart your Bird, you should remove the fuses for the lights.
Then once you have it running on just the ign. current, check your battery voltage
to see if it is higher than just 12.5 v
It should be more like 13.5 v plus. If not you might have a lack of charging voltage.
Should that be the case you may have regulator/rectifier problem.
If charging OK, just keep the batt charged.