Michael,
I have never heard of the blue wire used to control the relay. This may be
affecting your alternator output. I would use the "X" circuit. See Bentley.
 Next, I would go to my local FLAPS and have them test my battery/charging
system. They should check the battery capacity and the charging system with
all consumers on. The test is free and the guys are always glad to have an
excuse to get out of the store.
Ken Lewis
http://neksiwel.20m.com/