When I bought this TR7, the previous owner, the late John Amos, did warn me that there was an electrical fault in that the voltmeter would fall to the red when you put the headlights on. He had fitted a new alternator recently, presumably in an effort to cure this, but without any success – the voltmeter would sit nicely in the central position, but still fall rapidly into the red on the left, meaning that the battery was discharging.
I ran a few simple tests on the battery using my multimeter (more details in the picture captions), and everything seemed to be good there, both in terms of the I could not do a load test with my modest equipment so it is still possible that the battery has an internal fault, but the more likely scenario was a problem either with the voltmeter itself causing it to give a
