I searched but didn't find this question.

A couple of years ago I installed the CS130 alternator upgrade in my 69. It has worked very well but it failed the other day so I had to replace the alternator. As a result I am doing some double checking of my system.

I tied the blue/brown wires together as shown in Wes' tech article. This is connected to the "L" output. I ran a new wire to the block behind the battery to connect the "S" (sensor) output to. (Same concept as Wes' connecting it to the back of the alterantor but I thought it may get a more accurate sense of voltage). The "F" and "P" outputs are not used.

This configuration works but it means the "S" connection is always hot. With the stock external relay setup it it hot only with the key on. Is this a problem?

I also did not get the "gen" light when the alternator failed. It does come on with the key in the "ACC" position and when it is in "crank".

The system works OK, but I am just a bit concerned about the "S" wire being hot all of the time.

Thanks

joe

Hmmm, any thoughts?

Sounds like you've got it wired up just fine. The 'L' wire is fed from the GEN lamp and serves two purposes. First, it excites (enables) the voltage regulator (on most anyway), and second it allows the regulator to show a failure by grounding the 'L' wire internally. Sounds like when your alternator failed, perhaps the regulator was toast and didn't have enough brian cells to ground the 'L' wire and light the light.

The 'S' terminal being hot all the time is normal. Sounds like you're aware that it's a voltage sense terminal. It's connected to battery power - typically at the main power distribution point. As a result, it will be hot always. Many folks connect the 'S' terminal directly to the B+ terminal on the back of the alternator which effectively disables the remote sensing feature altogether.

Connecting it to the horn relay buss bar would have been a better choice than the terminal block behind the battery IMHO. The horn relay is the main power distribution point and you want it to be well regulated. There will be a slight voltage drop between the battery terminal block and the horn relay, and that will show up as a slight change in system voltage depending on the load and charge rate. But in any event, I'm sure you're setup will perform better than the OEM mechanical regulator setup in terms of higher current capacity and better regulation.

Thanks Dave. I like the suggestion of sense lead to the horn relay. It would make it more senstive.