Jaguar Repair: Battery drain, oil grease, jaguar xj6

Question
Jaguar XJ6 S3 4.2litre 1982

Hi,

My battery is losing its charge and becomes flat over about 2 weeks. Have replaced battery twice with new over last three months. Alternator is producing 13.9v at both 2500rpm and idle speed. However, after a run the battery only shows about 11.5v.
I have disconnected battery earth and connected an ammeter in line with earth and terminal and with everything switched off it is not showing any current draining the battery. Any ideas?
Thanks in anticipation.
Paul

Answer
Sometime relays will stick and cause circuits to draw current. Your problem appears to be intermittent. When your battery is being drained down, you can start removing fuses until
you find the circuit that is causing the problem. Also make sure there is no oil on the battery. Oil or grease on the battery will cause the same problem. Clean the battery, box and cables
and degrease your engine and make sure that oil, grease and dirt is not part of your problem.
I hope that this helps. Sammie