Single wire alternater upgrade

[DARREN LILLY]

Hi I put a 150 amp single wire alternater upgrade plus did the amp meter bypass at the same time on my 360 engine but doesnt appear to charging. I terminated the red charging wire to the amp meter back at the alternater & removed both the red & yellow wires from the amp meter & spliced them together. I ran a wire from the alternater to the starter solenoid with a fuse in between. Ive tried revving it to see if it would cut in but made no difference, have I messed something up. Copied this from the mad electrical site but didnt see anything on changing to a single wire unit.

[rocklaurence]

Seems like you've got it setup correctly. Only question/comment is that you should have the heavy wire from the Alt post to the solenoid-like you have. And you should have a good ground wire to the case of the alternator. Im not sure what your doing with the old Charge wire. Leave them disconnected/removed. Check the idle voltage with a meter--it should be approx' 13.5-14 volts

[tgreese]

How do you know it's not charging? As rocklaurence points out, the voltage regulator in the alternator should hold the system voltage above somewhat above the full voltage of the battery. With everything off and the battery fully charged, the battery voltage should be 12.6V. The battery charger can pack in a little more charge, making the battery voltage something like 13V right after charging.

I'm going through this likely in more detail than you need. Please excuse my telling you anything you already know - I just want to be sure to cover anything that might be missing.

I assume that this is a Delco 3-wire alternator (10SI or 12SI) that has been converted by the seller to 1-wire operation. I also assume that the Aussie versions of these Jeeps are the same electrically as the NA examples.

The Mad site won't tell you a lot about the 1-wire alternators, other than they are against them. Both the 1-wire and 3-wire connect directly to the battery when the ammeter is eliminated. Normally alternator current goes from the alternator through the bulkhead connector in the firewall, to a splice that feeds the dash and lights. From there the excess current goes to the ammeter, and from the ammeter goes back to the firewall bulkhead connector and to the fusible link that connect to the starter solenoid. The solenoid is a direct connection to the battery. It's the resistance of the battery to the excess current from the alternator that gives the voltage above the battery voltage. Battery voltage plus alternator current times battery internal resistance equals 13.5-14V. This is the voltage that the voltage regulator regulates.

You need to keep a connection from the battery to the splice that feeds the dash and lights. You can use either wire going to the bulkhead for this purpose. When I converted my J20 to a voltmeter, I disconnected the red wire from the alternator (the charge wire) from the bulkhead and ran it directly to the starter solenoid (battery connection) via a new fusible link. I spliced the ammeter wires together. This establishes a direct connection from the previously existing fusible link to the dash and light splice. The former charge wire from the alternator bulkhead connection to the dash and lights splice was abandoned in place (it goes nowhere now).

I used the original wire from the alternator to the bulkhead to connect to the solenoid. If you applied power from both sides to the splice for the dash and lights, only one side is needed but it should still work. From reading above, it seems like you used a new wire to the solenoid and used the existing wire from the solenoid to the bulkhead to power the splice.

This should work exactly the same for a 1-wire. The 3-wire installed in a Jeep is essentially a 2-wire. The 3-wire has a voltage sense connection from the 2-prong plug that immediately bends back and connects to the charge wire. This wire connects to the voltage regulator is used to determine more or less current output, raising and lowering the voltage by the battery internal resistance covered earlier. This connection is made internally with the 1-wire alternator. The other wire to the 2-prong plug is from the ignition, and both provides an alternator light (when present) and a "bootstrap" voltage to start the alternator charging. As you understand, the 1-wire alternator has different internal electronics that allow the alternator to bootstrap without this external connection.

That's it - don't know what more to tell you. Should work if connected this way. There is a sticky thread on IFSJA that is titled something like "ammeter bypass" that discusses this a lot more.