I have 1996 n15. runs ace. This morn turned key, itmoaned a bit then started. Switched off and turned key again - just a click, no go. Attached fully charged battery and tried again, Again a click and no go. Connected 4 amp charger and ammeter showed 2 amp rate. With charger still connected I observed ammeter whilst assistant turned ignnition key - expected thermal cut out. Instead ammeter just moved up to 3 amps indicating a very small pull on the battery. I am puzzled. Any ideas please?