Battery Drain Overnight? - Impala Tech
Electrical & Wiring Troubleshooting electrical problems

 
LinkBack Thread Tools
post #1 of 8 (permalink) Old 12-18-2015, 02:57 AM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Washington
Posts: 203
 
Battery Drain Overnight?

So trying to figure this out is literally driving me insane.

I did perform a parasitic test and discovered that a constant rate of 2.78-2.80 amps are being drawn and draining the battery.

After finding this out I started pulling all the fuses to see if the draw would go away on one of circuits but that didn't happen. I also pulled the wires connected to the accessory and battery circuits (aftermarket radio and stereo system). That didn't work either.

I started to think about new stuff I added in right before finding out about the draw like a new Grant classic steering wheel and putting in new door jamb dome lamp switches. I unplugged the new horn wiring, ungrounded the relay (because I was messing with that beforehand due to the horn not shutting off), and unplugging the horns under the hood and the draw was still happening. I figured that the door jamb switches wouldn't matter since they're probably connected to one of the lamp circuits. But I'm wondering if that's actually the problem and if the connection there is staying hot and causing a draw. Maybe I'll try disconnecting those tomorrow and seeing what happens.

I also tried unplugging the alternator, messing with the glove box light, unplugging the MSD ignition box, and starter coil. I also performed the old fashioned test of disconnecting one of the battery cables overnight to see if the battery was actually discharging by itself but I woke up to a full battery.

Any other ideas? This is an old car so there isn't a lot that could be causing a draw.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
Classiccarman is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 12-18-2015, 10:01 AM
Moderator
 
Join Date: Jan 2006
Posts: 12,381
 
Unplug the battery! Your short could be internal to the battery (plates shorting out due to lead sulfate being shed off the plates by a faster than usual charge).

Once you know it is external to the battery and you have unplugged all loads that leaves just the wiring as an issue. You may have crimped a wire tightening something down with the paper thin insulation slowing the discharge down but not stopping it from shorting out.

Big Dave
Big Dave is offline  
post #3 of 8 (permalink) Old 12-18-2015, 02:24 PM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Washington
Posts: 203
 
I noticed something when I do the parasitic test every time. When I put the positive lead on the negative terminal and the negative lead on the negative post on the battery, I always get a spark between the negative multi meter lead and negative battery post. Sometimes the multi meter goes crazy and starts jumping around till it hits 2.78-2.80. So I don't know if that's a battery problem or normal when there is a draw.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
Classiccarman is offline  
 
post #4 of 8 (permalink) Old 12-18-2015, 04:55 PM
Senior Member
 
Join Date: Apr 2014
Location: North Dakota
Posts: 130
 
Garage
Just a little confused, If your checking amperage across the positive and negative side of the battery, that wont work. Amperage needs to be checked in series and not in parallel. A 2.8 amperage draw is equivalent to the draw of a head light. That's a heavy draw. Moisture and dirt across the posts of battery can cause a draw. You can also have a bad ground, current feeding back from ground. It sounds like your checking all the right things, just need to keep looking. Not sure if your car has an insulated positive junction, on your radiator support by the battery, but if so I would check that. Like Dave said could be wiring harness, check for obvious damage. Also pull apart your bulk head electrical connector at the firewall. Look for moisture, dirt, bad connectors. Blow out the connector, clean the contacts and put dielectric grease on the contacts. Good luck, keep up informed.
6366 is offline  
post #5 of 8 (permalink) Old 12-18-2015, 06:24 PM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Washington
Posts: 203
 
I'm checking amperage by doing a parasitic test which is touching the negative terminal with the multi-meter positive lead and touching the negative battery post with the negative multi-meter lead.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
Classiccarman is offline  
post #6 of 8 (permalink) Old 12-18-2015, 07:40 PM
Moderator
 
Join Date: Jul 2009
Location: Canada
Posts: 1,391
 
You are not measuring amperage correctly. You need to disconnect one of the battery terminals, and use the Ammeter in series with the battery terminal and the cable.

Two doors, four doors, wagons, and ragtops.
jayoldschool is offline  
post #7 of 8 (permalink) Old 12-18-2015, 10:29 PM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Washington
Posts: 203
 
Quote:
Originally Posted by jayoldschool View Post
You are not measuring amperage correctly. You need to disconnect one of the battery terminals, and use the Ammeter in series with the battery terminal and the cable.
That's what I've been doing. The negative terminal/cable is disconnected from the negative post on the battery while I'm doing this. Then the positive lead on the multi-meter is attached to the negative terminal/cable while the negative lead on the multi-meter is attached to the negative post on the battery. That's how I figured out the draw.


Update: I think I narrowed down the draw even more. I remembered that I also replaced the positive battery cable. There are other wires that attach to the positive terminal/cable. One is the MSD ignition which I already debunked, one is the stereo amp which I already debunked as well, and the other powers the headlights (and I assume the taillights, etc) and has a O-ring connector at the end and connects to another O-ring that powers the lights. I disconnected that wire and the draw stopped. I know for sure that when I remade made this connection I ended up using 10 gauge wire instead of 12 gauge because I was out, so I don't know if that has anything to do with it but I'll replace it. I'll also have to follow the wires and see where they go.

1967 Chevrolet Impala 4 door "post" sedan
327 5.4L V8 - 3-speed TH350
Classiccarman is offline  
post #8 of 8 (permalink) Old 12-19-2015, 12:24 PM
Moderator
 
Join Date: Jan 2006
Posts: 12,381
 
Larger wire is just more expensive. It will not affect anything in the circuit as far as resistance, or impedance. It actually helps to carry additional amperage. I always increase the size of stock wires as the factory minimized the size to save a few pennies per car (which when you make three plus million cars a year can pay for a lot of dancing girls for the annual stock holders Christmas party).

Electrical troubleshooting is so labor intensive that no one does it anymore. It is always cheaper to throw in a new American Automotive Wire wiring harness and say done! At over a hundred dollars an hour to troubleshot you can have new wiring installed before you ever find the problem.

I never used to trouble shoot problems either, I would go to the bone yard and pull a factory harness out of a used car because back when I was working on these cars in my commercial garage they were not classics or collectables but just a used car.

Big Dave
Big Dave is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Impala Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome