Battery Draw

[Rineheitzgabot]

What might the most probably cause of my battery draw, be?

I just converted to an alternator, and after driving it several times, and it working fine, I let it sit for a week. After that week, the thing wouldn't even "click". It was dead as Hitler.

As always, thanks for your input.

[Donnie]

dead battery

Did U use a 10si GM alt? If yes, how many wires, & how do U have it wired?

[Rineheitzgabot]

Yes. Delco 10si. Three wires.

Red 10 ga. to solenoid
Red 16 ga. switched 12 volts
White 16 ga. to switched 12 volts (I don't have any ammeter)

[superstator]

Have you double checked all those wires for voltage with the ignition off? There should be voltage at the main output post (BATT) on the alternator, and nowhere else.

[Daurie]

This is where a DC capable clamp meter is invaluable. I can't tell you how many drain issues a clamp meter made short work of. Clamp on the batt lead and start pulling fuses one at a time. Of course it may be on an unfused cir too but still easy.

[Rineheitzgabot]

Have you double checked all those wires for voltage with the ignition off? There should be voltage at the main output post (BATT) on the alternator, and nowhere else.

Thanks. I checked the two wires coming from the plug on the alternator, and found that the white one was indeed showing 12V with the key off. "I must have misunderstood something in my instructions", I said to myself. So I followed Superstator's advice and put the white wire on to a 12V source that is switched with the ignition. Now, the battery drain is worse and the engine won't shut off with the key. I read about the "non-shut off" problem, and thought it would be certainly fixed by having BOTH wires hooked to switched 12V; but not true.

Today, I left the white wire unhooked all day, and it seemed that there was no drain on the battery.

I was not able to follow the instructions that I read on the internet (LRFAQ.com, Bayou Rovers, etc.) because they all talk about tapping into the ammeter, which I do not have. I had to draw some conclusions based on what I thought was needed to make the thing work. Perhaps this is where my problem originates.

Any suggestions are welcome.

[superstator]

Which terminal on the alternator is the white wire connected to?

[siiirhd88]

Check that you don't have the small wires on the wrong alternator terminals. The #1 alternator terminal is usually the white wire on the generic plug, and can be connected to the small brown with yellow trace wire that goes to one side of the "ignition" lamp, the other side of the lamp goes to the ignition switch when the key is "on", usually a white wire (unfused, ignition "on" wiring). The #2 alternator terminal is usually the red wire on the generic plug. This is the 'sensing' wire, and can be connected to the small brown wire. This wire should be connected to the battery post on the starter soleniod, near to the battery and at the location where most of the actual load wires connect. These are the brown wires, unfused, and are powered all the time. In actuality, the #2 alternator terminal wire could be connected to the large "BATT" post on the back of the alternator since the large wire is connected to the battery post on the solenoid, but itis better to 'sense' close to the loads and battery.

The above small brown/yellow and small brown wires assume you had a Lucas alternator to begin with.

When the ignition is turned on and the engine is not running, there is a voltage drop across the ignition lamp from the white ignition "on" wire on one side (12 volts) to the brown wire with yellow trace, connected to the alternator. When the engine is started and the alternator has an output, the voltage is equalized across the ignition lamp and the light goes out.

I have never had a problem with the engine continuing to run with a Delco in a Series, but my Truimph TR3 with a Delco, wired exactly the same, needs a toggle switch to isolate the ignition circuit. I dunno why....

Bob

[superstator]

I feel like I should qualify my original advice a little: there are a lot of diagrams that have you connect the sense wire directly to the battery rather than go through the ignition, i which case both that wire and the output will have voltage with the ignition off. If your white wire is connected to sense (#2), and connected to the battery elsewhere, that would explain the engine running with the key off when you connected the other end to a switched source.

[Rineheitzgabot]

Superstator,

I have made a few discoveries, and will let you know what I am come up with soon. Your help is appreciated.

[Rineheitzgabot]

Which terminal on the alternator is the white wire connected to?

Thanks again for your help.

The white wire on the alternator is on the right-hand terminal. This is viewing the alternator from the front (where the pulley is mounted on the alt.), and the plug being at 10 O'clock. Yes, the plug is tucked under the manifold and is close to the engine.

I bought the plug from the local auto parts store, as the alt. did not come with one. It is directional, so it can only fit on, one way. I assumed that they knew what they were doing when they made the plug;maybe they don't. What is the job of the spade terminal that I described? Is it the "on" wire, or the sense wire?

Practical observation: I leave the white wire unplugged and two things happen that I cannot understand: 1) The battery stays charged between uses (this can be days at a time; which is normally how long it took for the battery to die). And 2), It appears by the voltage reading on my voltmeter that the alt. is charging when the motor runs; even without the white wire hooked up. Neither of these two phenomena can I explain. It appears that the white wire, does not need hooked to anything, for the alt. to do it's job.

Any thoughts?