Ralph, I have fitted the volt meter today to the suggested white wire, although there were a few, but I tested it first and it seemed to do the job, it was a thin gauge wire.
Anyhow, I put the new gauge on the battery terminals and the battery was showing 12.4v and when the engine was running it was 14.4v.
When I connected it to the white wire turned off but with ignition on it started at 12.4v but steadily dropped down to 11.8v when the engine was running it was reading up to 14.7V and dropped slightly to 14.5v with acceleration.
Does this seem ok to you, what power could be lost when off connected to the white wire and gain more when running? possible drain somewhere, but nothing was on, power dropped to 14.2v with 500W of lights on.
I’m not to fussed as it’s there mainly to monitor the alternator return
Any ideas?