[Healeys] Electric Draw

[Gil Rockwell]

Hi Price,

 

The easiest way to find the phantom draw is to put a 12 volt bulb (use a socket for the bulb with a couple of pieces of wire to connect to the battery using "alligator clips" if available) or non-LED test light in series with the positive lead of the battery cable (at the battery) and with the ignition off, look at the bulb.  If glowing, then start disconnecting one item at a time until it goes out.  If the diode in the alternator is bad, disconnecting the positive lead at the alternator will extinguish the light.  Heat may cause the diode to "leak" current and once it cools down, it may stop, so it may be heat dependent.  In any case, an alternator repair shop can test and replace it for you.  You also can buy, typically at NAPA and replacement diode assembly and install it yourself, not hard to do, use an impact wrench to remove the pulley nut and then the screws holding the case together and slip it apart.  The hardest part is holding back the brushes when re-assembling, but there are holes that a straightened paper clip will fit in the hold the brushes back until you re-assemble.  If not the diodes in the alternator, it can be anything electrical, so disconnecting obvious loads individually will always find the culprit.  Not disconnecting more than one load at a time is important so that you don't go down a "rabbit hole" chasing many things at once.   If you have a radio, that may be a good place to start, lights are always a possibility, have you checked the brake lights?  Are they staying on?  Pulling the fuses, one a time can ease the task of finding a circuit that is draining the battery.  If the battery disconnect switch is truly "off", there should be no current flowing from the battery and the voltage should remain within a few tenths of a volt of the original reading  when measured at the battery terminals after shutting the car off, even a day or two later.  

 

I can answer more direct questions after you have tried a few of the above suggestions. 

 

Gil

61 BT7

 

-----Original Message-----
From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of R. Lindsay
Sent: Friday, June 07, 2019 8:47 AM
To: Healey List
Subject: [Healeys] Electric Draw

 

For the past few weeks I have been fighting a parasitic draw on my BJ8. It was running about .48 amps and would drain my battery in a day or so. I was told by a mechanic that a diode in my alternator must have blown therefore causing the draw. He also mentioned that my ground wires in the boot were loose which he tightened. I brought the car home, turned off the power in the boot and 2 days later the battery was dead. 

 

So, here’s what I’ve done. I jumped the battery and started the car and ran it for 10 minutes. I disconnected the charger and tested the battery - 12.48 volts. I then removed the cutoff switch and bolted the grounding wires together. I tested for a draw and got a zero reading. That was last night. I went out this morning (12 hours later) and the battery reads 12.33 volts. 

 

My questions are 1. Is .15 volts a reasonable drop in voltage for a sitting car in 90 degree heat and 2. Can a diode in an alternator work sometimes and not at others. If it’s either “good or bad” all the time, I guess I need to presume the alternator is not the source of the draw. If a .15 volt loss over 12 hours is reasonable then removing the cut out switch in conjunction with presuming the alternator is good (as it works fine now) solved my problem. 

 

What does the wisdom of this great resource think?

 

Price Lindsay

 

Cell: 630-841-6300

Email: 050.rpl at gmail.com

 

Sent from my iPhone



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/healeys/attachments/20190607/c2d08185/attachment.html>