Charging Voltage improved
 

So with a nice warm holiday day I decided to give the 1995 940 some attention, started with swapping the wheels front to back, found I needed new rear pads changed those and then hoovered the car (full of dog hair), This prompted the battery to die with the doors open all day so I then decided to to check the charging voltage, which I had noticed problems with before.

Warm running with headlight (dipped)
Alternator = 14.1V
Battery=13.2V (idle), 13.4V (raised)

Losing nearly half the charging voltage at idle, wasn't too impressed. I have previously found and rectified problems with the main + battery terminal crimp (losing near 1V through the + battery crimp).

After probing around with the multi-meter I found most of this was being lost via the connections near the alternator. On the blue earth cable (attached to the inlet manifold) and the main output red wire to the starter (in-turn linked to the battery by the heavy starter cable). These crimped cables are looking sorry for themselves with the connectors fairly white with corrosion and the stranded copper fairly black. Ideally the correct thing to do is get a new cable/connectors, but I wanted to get an immediate improvement and couldn't easily find the cables or right connectors on-line. I wanted to confirm my theory, so after some experimentation I came up with a solution.

Soldering is a good way to improve these things (if you can avoid solder creeping into the cable), but with these old dirty corroded connections it wasn't taking. I also didn't want to removed the crimps and potentially weaken them.

The solution was to either scrape the area around the end of the copper wire and the copper wire itself with a sharp screwdriver, or use a power file to grind it down to shinny copper and connector (powerfile worked well for the + alternator connector). Then you can place a solder 'cap' over it. Its not ideal as you aren't getting solder into the join and could delaminate off eventually, but it works for now.

After cold restart with lights
Alternator = 14.4V
Battery= 14.1V

I have a dash volt meter for the battery, and this now shows mostly around 14V with the lights on or off (have DRLs).

Next time I'll try the big earth cable that goes to the block and chassis.

For a longer term solution the alternator ground cable is easily replaceable, but the other cables are a bit more integrated, requiring fresh cable + joiner or a soldered sleeve to the cable and connector somehow.

The connectors at the starter seem in much batter shape that the more exposed ones at the alternator and battery.