Battery & Charging

Power Cables: Assuming I wouldn’t get what I specifically wanted from anywhere, I decided to make my own cables out of 25 mm2 x 170 Amp cable. This would ensure the cable runs and terminals were neat and tidy.

One thing I was particular about was the orientation of the terminal ends. E.g. my earth strap goes from the negative power post bolt on the engine bay to the chassis...

Try going into a car accessory shop and asking for a 35 cm length of 25 mm2 x 170 Amp rated cable, black, with 10 mm ring terminals on each end, each being 90O out of phase with respect to each other and with the flat bit facing the vertical on the kerbside side, and horizontal on the chassis side... No, I didn’t... and no, I had no intention of doing so to see what reaction I would get. 

Ring Terminal Connections: These I crimped onto the cable using the vice. Tried soldering and blow-torching but these methods didn’t work for me. The solder just ran out of the little hole and there was melted and toasted plastic everywhere when I tried the blowtorch method. And when I did manage to get some solder to ‘take’, the joint and first inch or so of the cable was: a.) less than solid and b.) very very crispy - even with some heat shrink to hide the toasted bits.

So it was over to plan “B” and that was, crimping. A much neater job and I did put some heat shrink on the ends to further neaten things up.

I also sourced the correct size ring terminals for what I had to do. A small detail but it had to be right. It really was so important to get a good solid conductive connection.  

Terminals sizes used were:

  • 10 mm ring terminal (earth and main power cable to the battery posts)
  •   8 mm ring terminal (starter terminal)
  •   6 mm ring terminal (alternator “B” terminal)

Battery Cubbyhole: As my battery tray is under the wheel arch in its own little cubbyhole with the water-filled heat-exchanger directly above it, I needed to ensure the battery terminals were properly protected against potential water spray. So I went for the brass screw type and associated covers from CBS.


Alternator: I have a GM 10SI “one-wire-hook-up” alternator, so I thought I’d write something about how this alternator type fits in with my grand scheme of things.

Wiring up was straightforward; a single cable to the “B” [battery] terminal on the back of the alternator and one to the starter motor and job dun’... Not quite!

I had a major issue with the ignition warning light. On a GD LS setup, it’s just plug-&-Play to the dashboard loom via the engine plug; that being the ign’ warning light (NY and N, L14 wires.)  But I had to wire up my ignition “dummy light” [US terminology] directly from the alternator’s auxiliary spade terminal #1R. This to one side of the ign’ warning light and a 12v switched feed to the other side. A simple job but it took me an age of research to figure this out as I couldn’t get it to function as it was supposed to.

Initially, in my innocence [or is that ignorance,] I connected the ign’ warning light to the battery “B” post which meant the light was on all the time; it, now having a direct connection to the battery all the time.

To further complicate matters I then discovered, after an age of faffing around and troubleshooting, that the alternator’s auxiliary 1R and 2F terminals were bridged, or webbed to use the correct terminology. This meant that BOTH terminals had 12v all the time – even with the key out. This was because the 1R terminal was now always live and it always had a direct path back to the battery via the 2F (voltage regulator) terminal.

The theory is, a 12v switched feed to the bulb would provide the necessary differential to keep the bulb lit when the ign’ was on and would equalise the differential [voltage] when the engine was running i.e. no voltage differential, therefore, the bulb would extinguish. But it didn’t work like that because of the 1R & 2F terminals being bridged...

Totally mind-boggled me for ages, but I got it sorted in the end... I really could have done without this type of thing, but I did learn a lot about how an alternator worked.