Triumph Repair: tr6 not charging, battery cables, flame thrower

Question
hi howard,
i have a 74 tr6 and i cant seem to keep a charge on the battery for some reason.i put in a new altenator and theni even had that cheched to make sure its charging and it is.[auto advance checked it out and gave it a thumbs up]i also put in a new battery  at the same time.i have a petronics system in it with a 40t volt flame thrower coil.i may get two or three starts on it and then it goes dead.it runs fine with no problems.got any ideas?
txs bern

Answer
Hi Bernie,
You need to do two preliminary tests. First remove either of the battery cables and put a 12v test light between the cable and the battery post with everything turned off. If the test lights up brightly you have a draw that is running the battery down when the car sits.

Put the cable back on and put a volt meter across the posts of the battery (not the battery cables) Read battery voltage and then have someone start the engine and set the idle at abut 1500 RPM and read the battery voltage again and tell me what the readings were.

The aftermarket ignition system and coil have nothing to do with a battery going dead.

Let me know,
Howard