Voltage drop
Thread Starter
Pro
Joined: Aug 2004
Posts: 531
Likes: 10
From: Northford CT
Voltage drop
I had my first experience with a dead battery. The car sat for 2 weeks and it went dead, eventually I figured out it may be user error, I drove it with the mild2wild in quiet mode and forgot to change it before it sat. So I got the battery to a full charge 2.87v not running and left the hood open to monitor the drop. It is going down .1 volt per day, which is way more than my 07 which dropped .02v per day. The '10 does have more electronics (07 was mn6 no nav etc, 10 is a6 nav and all that) but the difference is alarming, I am thinking I have a drain like I have read about. I am bringing it in Monday to the dealer (first time) but wondered if anyone had any voltage measurements to share.
BTW I went back and read Shopdog's posts on the topic, very helpful. Also read that 30 milliamps is normal draw but I do not know how to translate that into a voltage reading...
Many Thanks.
BTW I went back and read Shopdog's posts on the topic, very helpful. Also read that 30 milliamps is normal draw but I do not know how to translate that into a voltage reading...
Many Thanks.
Last edited by Beezvette; Nov 15, 2011 at 06:57 PM.
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
There is no direct relationship/conversion for volts to milliamps. Milliamps is the only reference I've ever seen or used for car battery draw tests. Assuming the dealer does in fact do a draw test your car the result will be in milliamps. Then you can make comparisons.
You probably already know but, for the future you may consider using a Battery Tender any time you know the car won't be driven for a week or more OR consider a Priority Start device.
You probably already know but, for the future you may consider using a Battery Tender any time you know the car won't be driven for a week or more OR consider a Priority Start device.
Race Director
Joined: Apr 2007
Posts: 16,025
Likes: 1,656
From: Toronto, Canada
C7 of the Year - Unmodified Finalist 2021
There is no direct relationship/conversion for volts to milliamps. Milliamps is the only reference I've ever seen or used for car battery draw tests. Assuming the dealer does in fact do a draw test your car the result will be in milliamps. Then you can make comparisons.
You probably already know but, for the future you may consider using a Battery Tender any time you know the car won't be driven for a week or more OR consider a Priority Start device.
You probably already know but, for the future you may consider using a Battery Tender any time you know the car won't be driven for a week or more OR consider a Priority Start device.
Thread Starter
Pro
Joined: Aug 2004
Posts: 531
Likes: 10
From: Northford CT
There is no direct relationship/conversion for volts to milliamps. Milliamps is the only reference I've ever seen or used for car battery draw tests. Assuming the dealer does in fact do a draw test your car the result will be in milliamps. Then you can make comparisons.
You probably already know but, for the future you may consider using a Battery Tender any time you know the car won't be driven for a week or more OR consider a Priority Start device.
You probably already know but, for the future you may consider using a Battery Tender any time you know the car won't be driven for a week or more OR consider a Priority Start device.
Team Owner
Joined: Aug 2007
Posts: 136,140
Likes: 2,433
From: I live my life by 2 rules. 1) Never share everything you know. 2)
St. Jude Donor '11-'12-'13, '16-'17-'18
Hard to believe the static draw is only 30 ma (.030 amps).
(what's the amphour rating of a Vette starting battery?)
(what's the amphour rating of a Vette starting battery?)
Team Owner
Joined: Sep 2000
Posts: 25,032
Likes: 2,720
From: Far NW 'burbs of Chicago
St. Jude Donor '13
FWIW, we would occasionally leave our 2006 and now the 2009; sitting in a freezing cold garage for up to 3 weeks with no tender or charger. They always started normally.
That suggests that if your battery is going dead in that time, you either have an unusual parasitic draw (like to OP's MTW setup), or your battery is on the way out.
I finally bought a CTEK to use for those idle periods, trying to be nice to the replacement battery (old one was still ok, but had a hard life)
That suggests that if your battery is going dead in that time, you either have an unusual parasitic draw (like to OP's MTW setup), or your battery is on the way out.
I finally bought a CTEK to use for those idle periods, trying to be nice to the replacement battery (old one was still ok, but had a hard life)
Thread Starter
Pro
Joined: Aug 2004
Posts: 531
Likes: 10
From: Northford CT
Team Owner
Joined: Aug 2007
Posts: 136,140
Likes: 2,433
From: I live my life by 2 rules. 1) Never share everything you know. 2)
St. Jude Donor '11-'12-'13, '16-'17-'18
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Pro
Joined: Oct 2007
Posts: 679
Likes: 4
From: TremontonUT UT
Set meter to milliamps.
Disconnect negative cable from battery.
Connect one meter wire to Neg. cable and the other wire to Neg. battery post.
It will take about 5 min. for the car to "go to sleep".
Milliamps will count down to final reading during that time. Take your reading.
Race Director
Joined: Oct 2007
Posts: 11,367
Likes: 211
From: Edgewood Washington
St. Jude Donor '11-'12-'13-'14-'15
You can get a 'Current Clamp' for your meter that allows you to take readings without disconnecting the cable being measured.
They come in various ranges of sensitivity and max cable-diameter sizes.
You can also get a stand-alone meter if you don't have a fairly good Multimeter already.
They come in various ranges of sensitivity and max cable-diameter sizes.
You can also get a stand-alone meter if you don't have a fairly good Multimeter already.
Race Director
Joined: Mar 2010
Posts: 16,037
Likes: 831
Beezvette,
There are several inexpensive products you can use to monitor your batteries voltage and charge. However, what I'm reading here suggests to me your battery is on the way out. You might wanna replace it just to avoid being put in a bad situation down the road.
Chevrolet Customer Service,
Justin
There are several inexpensive products you can use to monitor your batteries voltage and charge. However, what I'm reading here suggests to me your battery is on the way out. You might wanna replace it just to avoid being put in a bad situation down the road.
Chevrolet Customer Service,
Justin
Melting Slicks
Joined: Apr 2010
Posts: 2,790
Likes: 108
From: On the coast North of SF bay
You can get a 'Current Clamp' for your meter that allows you to take readings without disconnecting the cable being measured.
They come in various ranges of sensitivity and max cable-diameter sizes.
You can also get a stand-alone meter if you don't have a fairly good Multimeter already.
They come in various ranges of sensitivity and max cable-diameter sizes.
You can also get a stand-alone meter if you don't have a fairly good Multimeter already.
Just remember when you use one of those attachments, you can only obtain a meaningful reading if you test only one of the legs, either pos or neg.
Many cables that are accessible are enclosed with a jacket and neither leg is readily accessible individually.
Last edited by pcguy2u; Nov 16, 2011 at 08:56 PM. Reason: fumbling fingers
Thread Starter
Pro
Joined: Aug 2004
Posts: 531
Likes: 10
From: Northford CT
Beezvette,
There are several inexpensive products you can use to monitor your batteries voltage and charge. However, what I'm reading here suggests to me your battery is on the way out. You might wanna replace it just to avoid being put in a bad situation down the road.
Chevrolet Customer Service,
Justin
There are several inexpensive products you can use to monitor your batteries voltage and charge. However, what I'm reading here suggests to me your battery is on the way out. You might wanna replace it just to avoid being put in a bad situation down the road.
Chevrolet Customer Service,
Justin
Thread Starter
Pro
Joined: Aug 2004
Posts: 531
Likes: 10
From: Northford CT
You can get a 'Current Clamp' for your meter that allows you to take readings without disconnecting the cable being measured.
They come in various ranges of sensitivity and max cable-diameter sizes.
You can also get a stand-alone meter if you don't have a fairly good Multimeter already.
They come in various ranges of sensitivity and max cable-diameter sizes.
You can also get a stand-alone meter if you don't have a fairly good Multimeter already.
Thread Starter
Pro
Joined: Aug 2004
Posts: 531
Likes: 10
From: Northford CT
Are you saying that you need bare cable to measure?
