Question about battery discharging
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,467
Likes: 43
From: Auburn MA
Question about battery discharging
Alright its that time of year here in the northern states where its time to put the toys away for the winter. Now My car has been off the road for a month storred outside for about a month now and I went to start it and the just clicked with not enough power to turn it over. The car is a 94 6 speed coupe the battery is brand new (Optima Yellow top) and the car is stored outside. Does the factory security system or passive keyless entry drain the battery in the matter of a month to the point where it wont start... is this normal
Advanced
Joined: Nov 2006
Posts: 61
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From: The one I'm in at the time. High country Colorado,Maui.
I have the same problem and so does one of my friends. As far as I can tell the alarm system pulls the battery down.
I thought the car had a battery saver switch the turned the power off if the battery fell below a certain level. If this is true mine doesn't work.
I went to Harbor freight and bought a little float charger for 6 bucks that I leave on all the time the car is stored. I haven't had a problem since.
I thought the car had a battery saver switch the turned the power off if the battery fell below a certain level. If this is true mine doesn't work.
I went to Harbor freight and bought a little float charger for 6 bucks that I leave on all the time the car is stored. I haven't had a problem since.
Advanced
Joined: Nov 2006
Posts: 61
Likes: 0
From: The one I'm in at the time. High country Colorado,Maui.
Are saying the Vette battery goes down in a few days? If so you may have another problem.
Mine would take almost two months before the battery was down. At least I had let it sit for that long and it still started. It seemed if the car set for more than three months it was dead.
Mine would take almost two months before the battery was down. At least I had let it sit for that long and it still started. It seemed if the car set for more than three months it was dead.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Even if you disconnect the battery, all lead acid batteries self discharge up to 1% each day. As the battery discharges, lead sulphate collects on the plates and lead sulphate is a good insulator and a fully sulphated battery is a door stop. ALWAYS periodically charge your battery if you aren't using the car (like once a week), or, buy a battery tender which measures the battery voltage and only charges the battery when its charge drops about 10% and turns off. Lead acid batteries do not like sitting long periods (4+ WKS) doing nothing.
Team Owner
Joined: Sep 2003
Posts: 20,179
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Get a battery tender. It will prolong the battery life during idle periods. Or put the Vette battery in your daily driver during the storage period.
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Racer
Joined: Oct 2004
Posts: 288
Likes: 18
From: Somerset PA
Bose Relay
I had this problem on my 89. I never could figure it out.
But, this summer, I replaced my Bose stereo with an aftermarket one, and it hasn't happened since.
I know there was some issues with the Bose relay not kicking off and it keeping power to the speaker amps. I'm not sure if that was my problem or not, but it's gone now!
You may want to check your Bose relay...
But, this summer, I replaced my Bose stereo with an aftermarket one, and it hasn't happened since.
I know there was some issues with the Bose relay not kicking off and it keeping power to the speaker amps. I'm not sure if that was my problem or not, but it's gone now!
You may want to check your Bose relay...
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
with all suggestions to far.It is true batteries don’t like to sit for extended periods. I would tend to think a new battery fully charged should be able to go a month though depending on outside temperature. I remember reading on the Forum several months ago where some people were having problems with yellow top (or red) batteries, been to long, can’t quite remember all the details.
The standard vette electrical system should draw between 20 to 30 milliamps of current when just sitting. You can measure this current to make sure there is no excess current drain. Although an ammeter is inserted in series with the battery cable, certain steps must be taken to get a true reading and for the test to operate properly. If interested, I can PM or post the information for you.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
i have seen in other gm FSM's (not in vette tho) that if you do not drive the car for eleven days (nice round number ???) you should disconnect the battery...no explanation given...elec systems identical to vette
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Who knows…. I have seen other service manuals and sometimes some service efforts are done to frequent or to excessive. Probably is a CYA type of effort. If a car can’t sit for 2 weeks, it would be a sorry reflection of engineering. I travel for work and go on vacation, come back in a week or two and the car starts just like it should, like I never left.
Who could own a car with that kind of requirement, the general public can barely put gas in their own car. And people would be flocking out of showrooms if they knew that was a requirement to own a car like that. You got to wonder what their thinking to have written something like that.
Who could own a car with that kind of requirement, the general public can barely put gas in their own car. And people would be flocking out of showrooms if they knew that was a requirement to own a car like that. You got to wonder what their thinking to have written something like that.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
its concrete evidence that gm electrical design has their heads in a dark place....obvious that they know about the problem but no fix....i have heard more than a few vette owners complain about 2-week death, the 11 day warning is appropriate.retired now, but disconnected my battery at the airport when going on business trips a while back...airport security guys were amused with me having hood up to discon battery to ''prevent car theft'' , but i was amused by regularly seeing someone else getting a ''jump''
btw, a ''low'' battery may have enough juice to start the engine, only to have an otherwise good battery murdered by the high charge rate of the 100+ amp output alternator.
Last edited by redrose; Nov 22, 2006 at 02:05 PM.
Tech Contributor
Joined: Aug 2006
Posts: 9,933
Likes: 103
From: Peoria Arizona.. Resident Gold Cylon
re:Discharging battery
I had a discharging battery prolem in my 1990. I bought a new high end replacement battery with both top posts and side posts. The postive top post plastic cover chaffed and made contact with the frame. End result the battery was discharging against the frame kiling the battery in days. Had no idea as the post is hidden away on the underside. Pulling the battery out and seeing the slight melt gave me the so thats whats happening inspiration. 
Goldcylon
Goldcylon
Instructor
Joined: Jan 2003
Posts: 233
Likes: 0
From: IL
battery drain
Are saying the Vette battery goes down in a few days? If so you may have another problem.
Mine would take almost two months before the battery was down. At least I had let it sit for that long and it still started. It seemed if the car set for more than three months it was dead.
Mine would take almost two months before the battery was down. At least I had let it sit for that long and it still started. It seemed if the car set for more than three months it was dead.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Disconnect the neg cable and put an ammeter in series between the bat neg post and the removed cable. Wait for the courtesy lights to time out and measure the leakage current. GM says it should be less than 50 milliamps, my 87 draws 27 ma. Pull fuses one at a time and watch the ammeter (pull the courtesy fuse so you don't have to keep waiting for the courtesy lights to time out). At night check for underhood lights, vanity mirror lights, map lights in the doors, console compartment light. Do you have a radar detector, aftermarket alarm or radio or audio amp? Check em.
Race Director
Joined: Dec 2000
Posts: 17,551
Likes: 26
From: El Paso Texas
I had a discharging battery prolem in my 1990. I bought a new high end replacement battery with both top posts and side posts. The postive top post plastic cover chaffed and made contact with the frame. End result the battery was discharging against the frame kiling the battery in days. Had no idea as the post is hidden away on the underside. Pulling the battery out and seeing the slight melt gave me the so thats whats happening inspiration. Goldcylon
Goldcylon
Tech Contributor
Joined: Aug 2006
Posts: 9,933
Likes: 103
From: Peoria Arizona.. Resident Gold Cylon
Pro
Joined: Nov 2005
Posts: 602
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From: North Bay Ontario
Just a little 'for what it's worth' experience to pass along - when I bought my '85 a couple of years ago, the seller said that there was a heavy draw in the circuit that controled the sport seats & power door lock circuit. There was a breaker in the fuse block that he had removed. I eventually got tired of manually locking the doors and one day, plugged the breaker in. The battery never went down even when sitting for a couple of weeks. Then one day, I'm vacuuming the interior and play around with the passenger power seat recline function. It worked okay (at least I thought). After sitting for 3 hours (yes 3 hours!) the battery was dead! I re-traced my steps and figured the sport seat must have been the culprit (since I had been warned about it when I bought the car) Sure enough the rocker switch in the seat bolester was shorting out. I guess the breaker was going on and off like a signal switch until the battery died. Changed the switch (it was definitely shot) and everything is staying charged now, for 3-4 weeks, which is as long as the car has ever sat during cruising season.
Tech Contributor
Joined: Aug 2006
Posts: 9,933
Likes: 103
From: Peoria Arizona.. Resident Gold Cylon
re:Shorting out Sport seats
Just a little 'for what it's worth' experience to pass along - when I bought my '85 a couple of years ago, the seller said that there was a heavy draw in the circuit that controled the sport seats & power door lock circuit. There was a breaker in the fuse block that he had removed. I eventually got tired of manually locking the doors and one day, plugged the breaker in. The battery never went down even when sitting for a couple of weeks. Then one day, I'm vacuuming the interior and play around with the passenger power seat recline function. It worked okay (at least I thought). After sitting for 3 hours (yes 3 hours!) the battery was dead! I re-traced my steps and figured the sport seat must have been the culprit (since I had been warned about it when I bought the car) Sure enough the rocker switch in the seat bolester was shorting out. I guess the breaker was going on and off like a signal switch until the battery died. Changed the switch (it was definitely shot) and everything is staying charged now, for 3-4 weeks, which is as long as the car has ever sat during cruising season.
Good suggestion to check for draining.