Battery Drain?
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
Battery Drain?
My battery has failed me twice now as I purchased the car two weeks ago.
Therefore, I set my DVM amp reading to 10 and connected the meter to the positive post to the disconnected positive battery cable and received a reading of .01 - .02. So far so good.
Then reconnected battery and put a test light between ther negative post and neagtice cable, no light, alternator is not drawing so far so good.
Here is my dumb question. In scenario 1 as I open the door the courtesy lights do not come on, should they? If I reconnect the positive then the courtesy light come on as the door is open.
The batter reads 12.4 volts with the engine off and 13.5 with the engine running. Is my battery suspect?
Therefore, I set my DVM amp reading to 10 and connected the meter to the positive post to the disconnected positive battery cable and received a reading of .01 - .02. So far so good.
Then reconnected battery and put a test light between ther negative post and neagtice cable, no light, alternator is not drawing so far so good.
Here is my dumb question. In scenario 1 as I open the door the courtesy lights do not come on, should they? If I reconnect the positive then the courtesy light come on as the door is open.
The batter reads 12.4 volts with the engine off and 13.5 with the engine running. Is my battery suspect?
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
The lights should come on when you open the door. Do the lights turn off a bit after the door closes? Rerun the test 1, connect up the test rig, roll the window down, close the door. Watch the meter and see what happens, then open the door and see what happens. When you close the door, the lights should go out and the meter should drop down to <20ma.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
No I dont think your interior light would come on, should have just made the meter read higher.The 13.5 volts is about 1 volt low but shouldnt cause battery to go down.If your not in a hurry charge your battery and disconnect it- check voltage and leave it sit a couple of days and check again.If it goes down not connected then its bad.Make sure alt. belt is tight and connections are good.
Instructor
Joined: Aug 2002
Posts: 124
Likes: 0
From: Williamsport PA
Battery Drain?
I replace the starter on my '71 . A friend of mine reconnected the wires,
he had connected the ground wire to a wrong post. The battery would only stay charge for a day or so - tracking the probem we found that
he had connected the ground back to the starter . I wish you luck in
finding the problem .
he had connected the ground wire to a wrong post. The battery would only stay charge for a day or so - tracking the probem we found that
he had connected the ground back to the starter . I wish you luck in
finding the problem .
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
With test #1, cable off of positive post and DVM set to amps between the post and off cable the door lights will not come on if door is open. Should the DVM complete the circuit and allow the lights to come on?
I have a guru coming to check the DVM today.
I have a guru coming to check the DVM today.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Originally Posted by SoCalErv
My battery has failed me twice now as I purchased the car two weeks ago....
13.5 at the battery with the engine running indicates the alternator is cranking as it should.
How old is the battery?
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
The car would not turn over, just that nagging click sound. As for the age of the battery I do not have a clue as I purchased the car approximately two weeks ago.
I checked the fuses in my DVM and they were toast, shouldn't lend your tools. New fuses installed will retest tonight
I checked the fuses in my DVM and they were toast, shouldn't lend your tools. New fuses installed will retest tonight
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Originally Posted by SoCalErv
The car would not turn over, just that nagging click sound. As for the age of the battery I do not have a clue as I purchased the car approximately two weeks ago.
I checked the fuses in my DVM and they were toast, shouldn't lend your tools. New fuses installed will retest tonight
I checked the fuses in my DVM and they were toast, shouldn't lend your tools. New fuses installed will retest tonight
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Melting Slicks
Joined: Jul 2006
Posts: 2,373
Likes: 6
From: Baltimore MD
Here is a great piece of advise,put in a power switch (battery disconnect),inline between your battery and positive cable.alot of older vettes have problems with battery drain,sometimes its very hard to find the problem,and i think all vettes should have these switches especially when they sit along time during winter storage.It also helps with car theft.I put one in my car and love it,should have done it a long time ago.This will solve your problem but not the reason for your battery drain.Plus it will make your battery last alot longer,it did mine im going on 10 years,but im going to buy another (optima) no fluid (acid) in it.
Last edited by Billysvette; Nov 14, 2006 at 06:28 PM.
Burning Brakes
Joined: Oct 2004
Posts: 920
Likes: 1
From: Shelby Township Michigan
I did a similar test on my brothers '76 to see what was draining his battery. I placed my DVM between the negative post and the negative cable. The interior lights worked and the DVM did complete the circuit. My meter is rated at 10amp max. If you exceed 10amps, you will blow the fuses like you have found.
You do not list what year vette you have. I found that my brothers problem was in the interior lighting circuit drawing .1amps and could not trace it down. I would recommend a battery disconnect for use at this point.
Good luck,
Dino
You do not list what year vette you have. I found that my brothers problem was in the interior lighting circuit drawing .1amps and could not trace it down. I would recommend a battery disconnect for use at this point.
Good luck,
Dino
Intermediate
Joined: Sep 2006
Posts: 39
Likes: 0
From: Cleveland Georgia
Originally Posted by 1stC3Vette
I did a similar test on my brothers '76 to see what was draining his battery. I placed my DVM between the negative post and the negative cable. The interior lights worked and the DVM did complete the circuit. My meter is rated at 10amp max. If you exceed 10amps, you will blow the fuses like you have found.
You do not list what year vette you have. I found that my brothers problem was in the interior lighting circuit drawing .1amps and could not trace it down. I would recommend a battery disconnect for use at this point.
Good luck,
Dino
You do not list what year vette you have. I found that my brothers problem was in the interior lighting circuit drawing .1amps and could not trace it down. I would recommend a battery disconnect for use at this point.
Good luck,
Dino
Later,
Johnny
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
After replacing fuses the DVM worked fine. Scenario#1 - .005 amps everything off, my clock does not work. With door open the courtesy lights come on with replaced fuses and draws 1.630. Battery volts engine off 12.34, engine running 14.40. Conclusion must of left the center compartment door open once and drained the system. I have a 1969 coupe. Thanks
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Originally Posted by SoCalErv
After replacing fuses the DVM worked fine. Scenario#1 - .005 amps everything off, my clock does not work. With door open the courtesy lights come on with replaced fuses and draws 1.630. Battery volts engine off 12.34, engine running 14.40. Conclusion must of left the center compartment door open once and drained the system. I have a 1969 coupe. Thanks
Drifting
Joined: Aug 2005
Posts: 1,430
Likes: 8
From: Hamilton NJ
Originally Posted by Johnny_Johnson
I had a similar problem with my '73. As it turned out the switch for the light in the storage compartment behind the seats was not adjusted properly and the light was on all the time even though the door was closed.
Later,
Johnny
Later,
Johnny
Best of luck
Melting Slicks
Joined: Aug 2002
Posts: 3,334
Likes: 4
From: Midland TX
Originally Posted by DWncchs
You say your clock doesnt work? Go back to your test with your DVM and while drawing .005 -fiddle with the clock adjusting stem-see if you can get the clock to try and rewind-maybe bump the cluster to shock it-if it does and sticks-it can draw at least 10 amps-that might be your intermitant short or draw.Or just disconnect the clock.In older vettes I have heard the clock is not fused and if they stick they have caught fire !!!!!!!!!!! Clock guy told me that.
I put a battery tender on mine. I have a secret audio radio on my Vette and don't want to lose the presets by disconnecting the battery (though I do like the anti-theft aspect of the battery disconnects).
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Originally Posted by SoCalErv
Looking for validation that a draw of .005 amps is ok with everything off. It is my understanding if I reach .010 or greater I have a drain problem?
For resistance I have a board with different resistors "labeled" so I can use them for comparison. Just for fun I will go see if my old style meter will tell me how much my test light draws,its easier to use.
Edit-Sorry Erv the old meter just buried the needle-but I looked at the bulb in the test light and it says 24v C5W...So I'm guessing thats 5 watts
Last edited by ...Roger...; Nov 21, 2006 at 10:56 AM.
