C5 Tech Corvette Tech/Performance: LS1 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

Battery drain

Thread Tools
 
Search this Thread
 
Old Oct 23, 2016 | 02:21 PM
  #1  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default Battery drain

Is there a common cause of battery drains? I unlocked the car in the garage a week ago and heard something running like a motor. It stopped after a few minutes. What about the hood light..how does that turn off?
Reply
Old Oct 23, 2016 | 02:33 PM
  #2  
c4cruiser's Avatar
c4cruiser
Team Owner
20 Year Member
Veteran: Army
 
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Default

A common source of a current drain given the noise you hear is a seat motor. Could be a bad processor or relay sticking for whatever side is making the noise.

The underhood lamp should go off just before the hood latches in the down position. There is a timer for the light when the hood is up. Should stay on for a short time once you open the hood.
Reply
Old Oct 24, 2016 | 11:54 AM
  #3  
ersatz928's Avatar
ersatz928
Melting Slicks
25 Year Member
Liked
Top Answer: 1
Top Answer: 5
 
Joined: Mar 2001
Posts: 2,668
Likes: 849
From: New Jersey
Default

My BCM itself was the root-cause of excessive current draw.
Reply
Old Oct 24, 2016 | 12:30 PM
  #4  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default

Tested the drain. Its 92ma with alarm off. With the hood up the light never (1/2 hour) shut off so I pulled it. How long should that light stay on?
Reply
Old Oct 24, 2016 | 01:28 PM
  #5  
Sydwayz's Avatar
Sydwayz
Drifting
Veteran: Air Force
Liked
Community Favorite
Top Answer: 1
 
Joined: Aug 2014
Posts: 1,402
Likes: 394
From: Virginia
St. Jude Donor '18
Default

I have a bad headlight motor, that I have not had time to fix. As such, I just keep it unplugged as it's a draw on the battery.
Also, unplugging both headlights is also a draw on the battery.
Reply
Old Oct 24, 2016 | 03:44 PM
  #6  
ersatz928's Avatar
ersatz928
Melting Slicks
25 Year Member
Liked
Top Answer: 1
Top Answer: 5
 
Joined: Mar 2001
Posts: 2,668
Likes: 849
From: New Jersey
Default

Check your "Inadvertant Load Relay", that's what is supposed to turn-off the underhood lamp after about 15 minutes.
Reply
Old Oct 24, 2016 | 08:36 PM
  #7  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default Charging

The battery in an ac delco nov. 2015 but its hosed. Hydrometer says cells are dead. 11.57 volts. 10 amp charger wont bring it back. I need to check the alternator, i believe thats what it is.
Reply
Old Jun 4, 2018 | 10:49 PM
  #8  
Amazing1's Avatar
Amazing1
Instructor
15 Year Member
 
Joined: Mar 2004
Posts: 226
Likes: 8
From: Hiram GA
Default

[QUOTE=8VETTE7;1593314399]Hood light is turned off by the BCM via relay #37 in the IPC fuse box after about 15 minutes.


Speaking of Relay #37, that is the one which I believe felt warm to the touch when I opened up the passenger compartment fuse box a few days ago. I've done the "test" where I sat in the garage to see if I could locate any lights that didn't or wouldn't turn off, but how in the heck could you see if the hood light goes off when the hood is closed?

Anyway, I've removed the bulb in order to figure out how to do a parasitic drain test using a multimeter, and just didn't replace it. If the bulb is out will this take care of any drain on the battery that might have existed before?

Also, can I go to an automotive store and buy a new replay that would replace my existing one? If this is the source of my drain, would this immediately solve that problem.

Thanks for your replies and patience. I really struggle with this stuff.
Mark M
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-1

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-2

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-3

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-4

10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

 Joe Kucinski
story-5

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-6

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-7

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-8

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-9

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
Old Jun 4, 2018 | 11:01 PM
  #9  
Vetteman Jack's Avatar
Vetteman Jack
Administrator
Supporting Lifetime
Veteran: Navy
St. Jude 20 Year Donor
25 Year Member
Veteran: Reserves
 
Joined: Mar 2001
Posts: 368,319
Likes: 24,777
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
Default

Moved to C5 Tech.
Reply
Old Oct 6, 2018 | 04:42 PM
  #10  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default drain

my c5 is pulling 70mA, is that too much?
Reply
Old Oct 6, 2018 | 05:04 PM
  #11  
c4cruiser's Avatar
c4cruiser
Team Owner
20 Year Member
Veteran: Army
 
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Default

Originally Posted by johnfin
my c5 is pulling 70mA, is that too much?
Yes; waay too much. And if you had that size of drain when you posted two years ago about your dead battery, chances are that the 70mA drain that you see now will kill the current battery you have in the car now. Look at the reply from 8vette7 for his comments about a "normal" drain and how to look for the cause.
Reply
Old Oct 7, 2018 | 06:51 PM
  #12  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default back on track

So I repaired the hvac motor speed controller and door motor and it looks like my current is around 23mA.(.152vdc / 6.6 ohms). Better!! How long can the car sit at 23mA and still start, ie 30 days?
Reply
Old Oct 8, 2018 | 08:31 PM
  #13  
bobs77vet's Avatar
bobs77vet
Race Director
20 Year Member
Conversation Starter
All Eyes On Me
Liked
 
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Default

interesting way to get to the milliamp draw.....how did you get the resistance reading?


my c5 is good for about 10-12 days and a solar panel battery charger plugged into the cigarette lighter seems to keep it for as long as I have I gone with out driving it.
Reply
Old Oct 8, 2018 | 08:37 PM
  #14  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default

Is that a trick question about the resistance? Ceramic resistor values are printed on the side and....... I checked it with the ohms setting on the meter (not connected to batt)
ohms law is a wonderful thing.
Reply
Old Oct 9, 2018 | 03:41 PM
  #15  
bobs77vet's Avatar
bobs77vet
Race Director
20 Year Member
Conversation Starter
All Eyes On Me
Liked
 
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Default

Originally Posted by johnfin
Is that a trick question about the resistance? Ceramic resistor values are printed on the side and....... I checked it with the ohms setting on the meter (not connected to batt)
ohms law is a wonderful thing.
no not really, it sounds like you checked it as an individual component and that makes lots of sense to me, I was wondering from the picture how you could have done it from the battery.
Reply
Old Oct 9, 2018 | 09:29 PM
  #16  
johnfin's Avatar
johnfin
Thread Starter
Drifting
10 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Jun 2012
Posts: 1,391
Likes: 73
Default drain

Its a very accurate way to check current drain. My meters were not giving me accurate readings. The resistor was not even hot after 1/2 of testing, it was cold.
Reply
Old Oct 11, 2018 | 03:27 PM
  #17  
reath1's Avatar
reath1
Burning Brakes
Supporting Lifetime
10 Year Member
 
Joined: Dec 2012
Posts: 832
Likes: 14
From: Lake Charles Louisiana
Default

Originally Posted by johnfin
Its a very accurate way to check current drain. My meters were not giving me accurate readings. The resistor was not even hot after 1/2 of testing, it was cold.
I just PM'd you.

Reath
Reply

Get notified of new replies

To Battery drain





All times are GMT -4. The time now is 07:04 AM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE