55.2-59 Battery draining

[Phungki]

So I was able to get back out there tonight. I have a -13.08 parasitic draw.

Started with the alternator. Disconnected the main wire, alternator to battery. nothing changed. Reconnected wire.

I disconnected the white (exciter) and the red (battery) wires and the draw went to -4.36. left them disconnected and disconnected the main wire again and the draw went to -0.07.

If I connect either the white or red wire again by itself the draw goes back to -13 again.

I do not have a diode on the white exciter wire. possibly the issue? from what I've read its supposed to allow the vehicle to be shut off, right? Something about stopping the current from traveling back. It does shut off normally.

ya'll have been great btw. I spend half my time frustrated and the other half happier than i pig in ....well you know. Is this normal?

[mr48chev]

Originally Posted by Phungki

So I was able to get back out there tonight. I have a -13.08 parasitic draw.
l?

The diode is a one way check valve for electricity that lets power go though that diode in the exciter wire to the alternator to tell it to charge but blocks electricity from feeding back from the alternator to the ignition. This is to prevent the feedback from keeping power to the ignition when you turn the key off.

Normally people either use the idiot light for the alternator or that diode to prevent the feedback. That is the fix for "I just put and alternator on my truck and drove it and it charged great but now the engine won't shut off when I turn the key off.

There should be no power though that wire with the key off. None=0

There should be no power at the pin for the exciter wire on the alternator with the key off.

This is how many of us who aren't putting in a complete wiring kit install an internal regulator Delco alternator


The white band on the diode shows which way the power flow goes.

There are two sets of diodes inside the alternator. The diode trio and the diode bridge. One or the other of those is what usually goes bad. They can be tested by taking the alternator apart but most parts houses don't keep them in stock. 25 years ago I was told by the counterman in a NAPA store that I was the only person in the area still rebuilding his own alternators. It isn't that common for an individual to do that anymore even though for someone with training and experience the degree of difficulty isn't that hard.

These diodes are again one way check valves for electricity

The tri diode


And or the diode bridge or Rectifier.


Those two from Summit cost almost as much as a lifetime guareentee alternator from O'Reilly's" That is why folks normally don't rebuild an alternator at home unless it is an "original" to the car or truck unit with the correct numbers that it left the factory and you are doing a 100 point restoration. Or you are cheap like me and hunt down the discount price parts and rebuild your own.

I really don't want you to take it apart because then I will have to write out a lengthy set of instructions and have to go take one apart to add photos to those instructions. I can do it and may do it as a separate tech thread some day.

[leegreen]

The setup Mr48chev posted will work. My understanding of connecting the voltage sense wire direct to the alternator output as shown in his picture is that it can lead to undercharging the battery. The alternator always senses it's output so it sets the output power to achieve the correct voltage right at the alternator, not the voltage at the battery or elsewhere in the system.

if you have big, thick, short wires between alternator and battery it should not matter as there is little voltage drop, but if you have a longer length, thinner or corroded wire and there is voltage drop between alt and battery the alternator wont maintain battery at correct voltage.

this wire I circled:

[Phungki]

Originally Posted by mr48chev

The diode is a one way check valve for electricity that lets power go though that diode in the exciter wire to the alternator to tell it to charge but blocks electricity from feeding back from the alternator to the ignition. This is to prevent the feedback from keeping power to the ignition when you turn the key off.

Normally people either use the idiot light for the alternator or that diode to prevent the feedback. That is the fix for "I just put and alternator on my truck and drove it and it charged great but now the engine won't shut off when I turn the key off.

There should be no power though that wire with the key off. None=0

There should be no power at the pin for the exciter wire on the alternator with the key off.

This is how many of us who aren't putting in a complete wiring kit install an internal regulator Delco alternator


The white band on the diode shows which way the power flow goes.

There are two sets of diodes inside the alternator. The diode trio and the diode bridge. One or the other of those is what usually goes bad. They can be tested by taking the alternator apart but most parts houses don't keep them in stock. 25 years ago I was told by the counterman in a NAPA store that I was the only person in the area still rebuilding his own alternators. It isn't that common for an individual to do that anymore even though for someone with training and experience the degree of difficulty isn't that hard.

These diodes are again one way check valves for electricity

The tri diode


And or the diode bridge or Rectifier.


Those two from Summit cost almost as much as a lifetime guareentee alternator from O'Reilly's" That is why folks normally don't rebuild an alternator at home unless it is an "original" to the car or truck unit with the correct numbers that it left the factory and you are doing a 100 point restoration. Or you are cheap like me and hunt down the discount price parts and rebuild your own.

I really don't want you to take it apart because then I will have to write out a lengthy set of instructions and have to go take one apart to add photos to those instructions. I can do it and may do it as a separate tech thread some day.

The 10 gauge wire in your picture goes to a junction box or ammeter? Mine goes directly to the positive side of the battery. Is that wrong?

No worries, tearing apart the alternator is above my pay grade as a mechanic.

I did pay attention to the orientation of the diode when I put it in. Pretty sure its correct.