Battery keeps going dead after a few days of sitting. I have the car at my mechanic and he says he thinks it is a relay behind the dash that is turning the radio on and draining the battery. I think he is grasping for straws. Anyone ever hear of this before?
A stuck horn relay was enough to kill the battery in my 78 CDV after a couple of days. The horns didnt work or it would have been a bit more obvious.
To find it you need to connect an amp meter (or properly sized light bulb for older cars) in line with the battery and start pulling fuses and relays till the load goes away. Then you know what area the problem is.
Just spoke to my mechanic, he cannot find and drain but still insists it is a relay for the radio (what relay?????????) He said the car was sitting for three days now and it started today with no problem. I will get the car back this weekend and start pulling fuses and relays again and see if I can come up with something. The funny thing is the weather has been warmer here in New Jersey for the last few days and I notice the problem more when the car sits when it is cold outside. It is an Interstate battery that is suited for the car. Could a bad cell do this?
Yes, a bad cell could do it but I don't think it would be intermittent. I had the clock in my '71 go bad and it would pull the battery down overnight. Noticed that the clock "window" was a little smoky looking and pulled the wire to the clock, problem solved.
;)
Did some digging and found some of the info from when I had the problem with my 78.
Battery voltage (after charging): 12.7
System voltage after start at high idle : 14.8
System voltage after a short drive at any rpm heater fan on high headlights on : 14.4-14.9
Amp draw with nothing on or un hooked : 0.006
Amp draw with clock fuse out : 0.0005
Amp draw with small alternator connector off : 0.0001
All seems fine and normal so just for fun and to see if my meter was working and get an idea how much it takes to kill the battery over night..
Amp draw with dome lights on : 6.4
Amp draw with glove box open : 0.9
Somewhere I read that up to 0.06 amps is 'normal' but I have not bothered to check any newer cars to confirm.
I was wondering if my mechanic was referring to the RAP (Retained Access Power) relay? I remember having a problem when I shut the car off the relay would click and the radio display would come on and off as the relay clicked until I opened the door. When I shut the door it would happen again so I removed the relay. I think that I either had to change the relay or the BCM. Any comments on this. I will still try a few experiments this weekend if the weather permits.
Also check the trunk and glove box lights.
Quote from: Dennis DiNorcia #19071 on January 08, 2008, 04:54:00 PM
Battery keeps going dead after a few days of sitting. I have the car at my mechanic and he says he thinks it is a relay behind the dash that is turning the radio on and draining the battery. I think he is grasping for straws. Anyone ever hear of this before?
01-11-08
Dennis, Have a friend listen to the "suspect" relay while you pull the NEG. battery cablle. the battery might be a little weak,also. If there is a SCHUCK' or big-A
,AUTO-ZONE parts store in your area, they will check your battery for you at no cost. They can tell you if the battery is good or not.
Good Luck,JIM
Got the car back saturday and there is no relay turning the radio on. Just as I suspected, the RAP relay was keeping the radio on and when the driver door was opened the switch would stick so of course if it does not make contact, the RAP will stay on but after 10 minutes it will turn off anyway. I took off the switch, cleaned the contacts and the RAP relay works fine. So it is back to the drawing board. The weather was in the 40's this weekend so the car started up and ran fine for both Saturday and Sunday. I will see what happens during the week when the temperature drops. I still suspect a bad battery that does not hold enough cold cranking amps to start the car in extereme cold. I have a 1995 Sedan that I let sit all week in the extreme cold and when I start it up on the weekend t starts up on a dime. I will keep you guys posted.
if the battery is discharging to ground fast it could be a sticky contact in the voltage regulator.
The contact temperature will be hot so you can point an IR gun at various relays/contacts/fuses while the car is cold to locate it.
You can also use the Ampere-Meter ring on your probe and check the wire harness starting from the battery up, to understand where current passes while the car is stopped, this should give you an idea where the issue is located.
I had some similar issues on my 6v 1947 Cadillac, and while the culprit was found using the 2 methods above, I have since installed one of those green knob switch on the ground battery post and always disconnect the battery at night and storage, just to be safe.
Started the car three days in a row and it started up just fine. Weather was in the 30'2 though, so I don't see any problems yet. If it stays this temp, I will let it sit for a few days and see if it drains. It might be such a slight drain that it only happens after several days. If not, then I will suspect is is due to poor cold cranking power.
Tried to car this morning, temperature in the 20's and no start. Cranked very slow till it died. I am going to try and charge it up this weekend and I will again put a tester between the negative cable and ground. If there is no drain then I will keep it disconnected for a week and if next weekend it does not start, it will tell me the battery is not starting due to the cold weather. If it starts, then there is definitely a drain. I will follow up again as soon as I have something else to add.
Hello Dennis,
How old is the battery? (usually a number and letter code on the side)
How long has it been in the car?
What brand is it?
What is the CCA?
Battery is an Interstate and it was replaced in February 2007. The one I had before was not the one for a car with a heated windshield so when I was having a problem last winter with a drain in the battery it was replaced. later I found out it was the level compressor that was shorting out and draining the battery. When it was disconnected the problem stopped but this was after the battery was changed. I replaced the compressor and the car was fine all summer. I seem to only have this trouble in the winter. The CCA I belive around 800 but I could be wrong. I will have to check it tonight. By the way, I jump started the car last night and it started in an instant so I charged it up ran it for around 1/2 hour, shut it and it restarted. I took off the negative cable and put a test light between the battery and a ground and the test light comes on and then fades out quickly and stays out. I figure this could be the computer or radio memory. I will leave the cable off till this weekend and if it starts then I know for sure it has to be a short. If it doesn't, I will invest in a new battery. I think I will go back to the Sears Die Hard Gold. I never had a problem with these batteries before.
Quote from: Dennis DiNorcia #19071 on January 18, 2008, 08:31:01 AM
I took off the negative cable and put a test light between the battery and a ground and the test light comes on and then fades out quickly and stays out. I figure this could be the computer or radio memory. I will leave the cable off till this weekend and if it starts then I know for sure it has to be a short. If it doesn't, I will invest in a new battery. I think I will go back to the Sears Die Hard Gold. I never had a problem with these batteries before.
Dennis, I believe your car is a rather modern one, with some electronic devices. To check if a drain is present require a specific tool/procedure. I will try to explain it, but it's not easy in a foreign language...
Electonic modules in a car don't go to "sleep" immediately after you turn the ignition off; they can be "awake" for about 20 minutes. If you disconnect the battery to insert an ammeter, BANG, they go all to sleep immediately and you will read maybe 0.006A which is normal. GM (I used to work there in Switzerland) developped a tool to avoid what I described above. The tool is connected at the battery and the other end at the positive wiring. There is a switch to close or open the current path. For and aft the switch are contacts to plug the ammeter. To start the engine, the switch is closed, so the ammeter has no current flowing thru. When the ignition is turned off, the switch at the tool is to open. At that moment, all modules still get some current thru the ammeter. The trick is to survey the ammeter long enough till the modules are going to sleep. If you still have an important drain after 1/h, then the job is to take one fuse after the other until the culprit is found.
It's not an easy task, but on a modern car the sole one. This procedure is described in each shop manual if I'm remembering well.
Good luck!
Roger
Went out this morning and the wind chill in the 15's, connected the battery cable and the car started after sitting for three days. That rules out the battery. It's obvious my system of checking the short does not work so i will bring in tomorrow to an electrical specialist. i will post the results. Thanks to everyone for all the help and advise.
Car was at the electrical shop for about two weeks and I picked it up today. I was told they ran a alternator and battery check and it showed a bad battery. He changed it the day after I left the car and it sat for about a week and he started it yesterday and it started with no problem. I picked up the car today and used it all day and it was fine. I don't know why a battery (Interstate) would go bad in less than one year. Unfortunately he replaced it with another Interstate. I hope this one lasts longer than this one. I will see when it sits for a week since I do not use it daily when I am working. I will follow up if any change. Thanks for all the help.
Quote from: Dennis DiNorcia CLC 19071 on January 20, 2008, 01:34:13 PM
Went out this morning and the wind chill in the 15's, connected the battery cable and the car started after sitting for three days. That rules out the battery. It's obvious my system of checking the short does not work so i will bring in tomorrow to an electrical specialist. i will post the results. Thanks to everyone for all the help and advise.
Thats funny. Do you think the car feels the wind chill ;D I still think you are going to find drain of some kind. It might be the normal draw of components in a new car with all the computers etc. They all have some inherent drain, that in the case of a marginal battery, will kill it in a relatively short time. A new battery has much more reserve and may not discharge for quite a long time to the point that it will not start the car. The fact that cars today draw on the battery more than the old cars when they are idle, affects battery life. It is not uncommon for a battery to fail in less than 3 years because of the continuous charge and discharge.
One of the biggest "killers" of Batteries is very short trips, and lots of starting, and Night Driving also doesn't help either.
You see, the Starting of the engine, and the power used to drive the lights and the like, takes a fair bit of re-charging time.
At night, with everything going, there really isn't that much of a charge going back into the battery as the Alternator, or Generator, is working flat out to compensate for the current draw.
Daytime driving is the best time for replenishing the current that has been taken out whilst starting and the like.
Plus, if any of the Alternator terminals are a bit "Suss", then it is going to be hard to get the power back into the Battery.
Bruce. >:D
One modification to Tassie’s post: Daytime highway driving is the best for recharging the battery. Stop and go city driving is not as helpful.
Also you have to check the current output of the alternator, if some of the diodes are bad the voltage will look good but the alternator won’t keep up with the lights and other current draw. (ask me how I know)
One other thought: If the problem is temperature related and the garage where the car was tested was heated then the problem would not occur.
Glen
In reply to Glen, the car was left in the lot for the whole time so it was exposed to the cold. I kind of suspect the problem will reoccur, but for now I do notice a big difference in the cold cranking start. I will inform if this comes up again. Thanks to all.
Dennis,
I had the same problem with my Chevy.When you charge it,does the charger get hot,and does it read so that the battery is dead?
You might want to check your generator,there might be a short in it.The juice thats left in there just might be going straight to ground.
Had the gen rebuilt and its been fine ever since.
Joe