Cyclical Battery Drain
04-21-2015, 07:53 PM
#1
Cyclical Battery Drain
I recently (6 months ago) replaced my 05 coupe battery with a red top Optima. The car is my daily driver, and everything was great until about 3 weeks ago, when it started struggling to start after sitting for more than 8-10 hours. After pressing the ignition switch, there would be an audible click, click, click, and then the starter would finally engage and the engine would start. I suspected a short, disconnected my neg cable from the battery, and connected my amp meter between the two. Sure enough, it was discharging at about 3.75 - 4A. (Yes, amps, not milliamps; and yes, I disconnected the hood lamp and allowed the car to power down for 10 min before testing).
I then started trying to pull fuses one at a time, searching for the shorted circuit, when the discharge dropped to 5 mA. At first, I thought I had found the shorted circuit, but when I replaced the fuse, it remained at 5 mA for a few minutes, only to return to 4A. I began to realize that, regardless of which fuse I pulled, the discharge appeared to be cyclical - discharging and then returning to normal, only to start discharging again within a few minutes. This is driving me nuts, because I have no way of isolating the short. I do not have ANY aftermarket equipment, like a security system. I am beginning to wonder if its a battery failure, but its the cyclical nature of the discharge that has me puzzled. Any ideas?
I should note that my headlights are dim at low beams, but I think that has more to do with the lenses. I've got new ones from Robert and just haven't had the time to replace them yet. And I've also had to replace the fuse for the horn in the last couple of months, but removing the horn fuse did not solve the discharge problem described above.
I then started trying to pull fuses one at a time, searching for the shorted circuit, when the discharge dropped to 5 mA. At first, I thought I had found the shorted circuit, but when I replaced the fuse, it remained at 5 mA for a few minutes, only to return to 4A. I began to realize that, regardless of which fuse I pulled, the discharge appeared to be cyclical - discharging and then returning to normal, only to start discharging again within a few minutes. This is driving me nuts, because I have no way of isolating the short. I do not have ANY aftermarket equipment, like a security system. I am beginning to wonder if its a battery failure, but its the cyclical nature of the discharge that has me puzzled. Any ideas?
I should note that my headlights are dim at low beams, but I think that has more to do with the lenses. I've got new ones from Robert and just haven't had the time to replace them yet. And I've also had to replace the fuse for the horn in the last couple of months, but removing the horn fuse did not solve the discharge problem described above.
Last edited by Caspase-9; 04-21-2015 at 07:56 PM.
04-21-2015, 08:30 PM
#2
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St. Jude Donor '15
"In honor of jpee"
There are quite a few things to check before replacing the battery. But a simple way to find out what all of them are is to look through a search of CF Gen and Tech since there are about five or more threads per week. As a starter, make sure you have the original nuts on the battery, that the starter motor cables are not corroded or burnt, that both batt. cables are clean (ed) at the terminals---I assume you did that when you replaced the batt.---that the ground is secure, and if I recall, there are some items to be checked in the steering column/wheel which are unique to '05s. Also, there must be a switch of some kind associated with the '05-only requirement to park in reverse for the man trans---no info on what trans you have. And, of course, it could be in the switch itself. Advanced search in the red bar above will be most helpful unless someone chimes in with THE one answer for your problem.
04-21-2015, 08:39 PM
#3
Burning Brakes
It sounds like you're looking for a response from somebody who experienced the same issue that can point you straight to your culprit. I unfortunately don't have that answer, but I'll try and weigh in with the little knowledge I have on the topic.
It sounds like you have a pretty good grasp on how to locate a short already, so lets try and elaborate on that. My first recommendation is try and borrow a low amp clamp from somebody if you don't have one already. I've run into scenarios where connecting and disconnecting the battery can cause more even more trouble with some systems that are on timers and such. A low amp clamp is probably the most unobtrusive method on getting your amperage reading. Also, in a perfect world, a graphing meter with recording capabilities works wonders in these situations, but they may be a little harder to come by. Or harder to find somebody to lend you a high dollar piece like that.
Next, I wouldn't be so quick to reinstall a fuse after you've caught an amperage drop. Maybe try and walk away for an hour to make sure that the draw doesn't pop back up on its own with a certain circuit eliminated. Also, its good to have a source with wiring diagrams. Once you have located the circuit thats drawing, you need to see every module on that circuit and start unplugging accordingly. I will say that 90% of the time I've run into a parasitic draw, it ends up being something fairly obvious (glove box light, etc).
It sounds like you have a pretty good grasp on how to locate a short already, so lets try and elaborate on that. My first recommendation is try and borrow a low amp clamp from somebody if you don't have one already. I've run into scenarios where connecting and disconnecting the battery can cause more even more trouble with some systems that are on timers and such. A low amp clamp is probably the most unobtrusive method on getting your amperage reading. Also, in a perfect world, a graphing meter with recording capabilities works wonders in these situations, but they may be a little harder to come by. Or harder to find somebody to lend you a high dollar piece like that.
Next, I wouldn't be so quick to reinstall a fuse after you've caught an amperage drop. Maybe try and walk away for an hour to make sure that the draw doesn't pop back up on its own with a certain circuit eliminated. Also, its good to have a source with wiring diagrams. Once you have located the circuit thats drawing, you need to see every module on that circuit and start unplugging accordingly. I will say that 90% of the time I've run into a parasitic draw, it ends up being something fairly obvious (glove box light, etc).
04-21-2015, 08:39 PM
#4
There are quite a few things to check before replacing the battery. But a simple way to find out what all of them are is to look through a search of CF Gen and Tech since there are about five or more threads per week. As a starter, make sure you have the original nuts on the battery, that the starter motor cables are not corroded or burnt, that both batt. cables are clean (ed) at the terminals---I assume you did that when you replaced the batt.---that the ground is secure, and if I recall, there are some items to be checked in the steering column/wheel which are unique to '05s. Also, there must be a switch of some kind associated with the '05-only requirement to park in reverse for the man trans---no info on what trans you have. And, of course, it could be in the switch itself. Advanced search in the red bar above will be most helpful unless someone chimes in with THE one answer for your problem.
04-21-2015, 08:46 PM
#5
Team Owner
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St. Jude Donor '15
"In honor of jpee"
A couple guys who might know/help are "Ft. Morgan AL" and "cclive." If they don't chime in, send them a PM or EM with this thread attached for their opinion. I do think, from something that I recall, that the OnStar module can run at times independently of everything else. One other thing, do you hear anything running, like an electric motor? I'm thinking fuel pump but there must be others, too. And have you looked at the starter motor, altho that cyclical thing might rule it out?
04-21-2015, 08:51 PM
#6
A couple guys who might know/help are "Ft. Morgan AL" and "cclive." If they don't chime in, send them a PM or EM with this thread attached for their opinion. I do think, from something that I recall, that the OnStar module can run at times independently of everything else. One other thing, do you hear anything running, like an electric motor? I'm thinking fuel pump but there must be others, too. And have you looked at the starter motor, altho that cyclical thing might rule it out?
04-21-2015, 08:59 PM
#7
It sounds like you're looking for a response from somebody who experienced the same issue that can point you straight to your culprit. I unfortunately don't have that answer, but I'll try and weigh in with the little knowledge I have on the topic.
It sounds like you have a pretty good grasp on how to locate a short already, so lets try and elaborate on that. My first recommendation is try and borrow a low amp clamp from somebody if you don't have one already. I've run into scenarios where connecting and disconnecting the battery can cause more even more trouble with some systems that are on timers and such. A low amp clamp is probably the most unobtrusive method on getting your amperage reading. Also, in a perfect world, a graphing meter with recording capabilities works wonders in these situations, but they may be a little harder to come by. Or harder to find somebody to lend you a high dollar piece like that.
Next, I wouldn't be so quick to reinstall a fuse after you've caught an amperage drop. Maybe try and walk away for an hour to make sure that the draw doesn't pop back up on its own with a certain circuit eliminated. Also, its good to have a source with wiring diagrams. Once you have located the circuit thats drawing, you need to see every module on that circuit and start unplugging accordingly. I will say that 90% of the time I've run into a parasitic draw, it ends up being something fairly obvious (glove box light, etc).
It sounds like you have a pretty good grasp on how to locate a short already, so lets try and elaborate on that. My first recommendation is try and borrow a low amp clamp from somebody if you don't have one already. I've run into scenarios where connecting and disconnecting the battery can cause more even more trouble with some systems that are on timers and such. A low amp clamp is probably the most unobtrusive method on getting your amperage reading. Also, in a perfect world, a graphing meter with recording capabilities works wonders in these situations, but they may be a little harder to come by. Or harder to find somebody to lend you a high dollar piece like that.
Next, I wouldn't be so quick to reinstall a fuse after you've caught an amperage drop. Maybe try and walk away for an hour to make sure that the draw doesn't pop back up on its own with a certain circuit eliminated. Also, its good to have a source with wiring diagrams. Once you have located the circuit thats drawing, you need to see every module on that circuit and start unplugging accordingly. I will say that 90% of the time I've run into a parasitic draw, it ends up being something fairly obvious (glove box light, etc).
04-22-2015, 01:03 AM
#8
Check the positive battery cable at the back of the motor.
It can rub against the back of the motor, and wear through both the loom and the coating on the wire to cause a short to the back of the motor.
If needed, use zip ties and tie the cable back to something else to pull it off the motor.
Also, trace the alternator wire down to the starter as well, since it may have the shielding on it worn through and grounding out instead.
As for the rest, get the car into sleep mode, then start pulling fused and one by one in the both the engine fuse box, and the passenger foot well until you find the fuse to the module causing the problem.
If you have all the fuses out, and still getting the drain, then it's back in either the positive battery cables, or at the termination point instead (The starter).
It can rub against the back of the motor, and wear through both the loom and the coating on the wire to cause a short to the back of the motor.
If needed, use zip ties and tie the cable back to something else to pull it off the motor.
Also, trace the alternator wire down to the starter as well, since it may have the shielding on it worn through and grounding out instead.
As for the rest, get the car into sleep mode, then start pulling fused and one by one in the both the engine fuse box, and the passenger foot well until you find the fuse to the module causing the problem.
If you have all the fuses out, and still getting the drain, then it's back in either the positive battery cables, or at the termination point instead (The starter).
04-29-2015, 10:32 PM
#9
Battery main fuse 3
Okay, so I finally got a chance to start pulling fuses to check for the source of my short, and when I pull fuse 26 (battery main fuse 3) in the engine bay fuse box the parasitic draw drops from about 4A to 0.3A. I realize that 300 mA is still to high, but pulling battery main fuse 3 obviously had a huge effect. Pulling battery main fuses 1 and 2 had no effects when pulled individually and did not further reduce the draw when pulled in conjunction with battery main fuse 3. Any idea(s) how to further isolate the short? The battery itself can still be fully charged with my battery tender.
04-29-2015, 10:59 PM
#10
Team Owner
You're moving in the right direction working with the fuses. If you have Onstar, that would be a prime first place to start. I do not have it and mine draws 11-17 ma after it calms down. Funny because the meter will constantly move from 11 to 17 and back, it does not settle to a steady draw.
As for the battery, it can't be a defective battery because you are measuring high current draw outside of the battery. A battery could have some internal problem that would drain it, but the drain would not be measurable outside of the battery itself.
I believe that standard clamp meters are only good for measuring AC, so a clamp won't work here. Good luck in the continuing search...
PS...don't forget the interior fuse box also...
As for the battery, it can't be a defective battery because you are measuring high current draw outside of the battery. A battery could have some internal problem that would drain it, but the drain would not be measurable outside of the battery itself.
I believe that standard clamp meters are only good for measuring AC, so a clamp won't work here. Good luck in the continuing search...
PS...don't forget the interior fuse box also...
04-30-2015, 12:49 AM
#11
Cruising
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Possible solution.
I had a similar issue with a drain on my battery and I got info from another member to replace the ignition switch and all my issues were solved. I don't believe my drain was cyclical however I have read a lot about the ignition switches on these cars being pieces of ****. Good luck man .
04-30-2015, 01:07 AM
#12
I had a similar issue with a drain on my battery and I got info from another member to replace the ignition switch and all my issues were solved. I don't believe my drain was cyclical however I have read a lot about the ignition switches on these cars being pieces of ****. Good luck man .
04-30-2015, 01:07 AM
#13
You're moving in the right direction working with the fuses. If you have Onstar, that would be a prime first place to start. I do not have it and mine draws 11-17 ma after it calms down. Funny because the meter will constantly move from 11 to 17 and back, it does not settle to a steady draw.
As for the battery, it can't be a defective battery because you are measuring high current draw outside of the battery. A battery could have some internal problem that would drain it, but the drain would not be measurable outside of the battery itself.
I believe that standard clamp meters are only good for measuring AC, so a clamp won't work here. Good luck in the continuing search...
PS...don't forget the interior fuse box also...
As for the battery, it can't be a defective battery because you are measuring high current draw outside of the battery. A battery could have some internal problem that would drain it, but the drain would not be measurable outside of the battery itself.
I believe that standard clamp meters are only good for measuring AC, so a clamp won't work here. Good luck in the continuing search...
PS...don't forget the interior fuse box also...
04-30-2015, 01:46 PM
#14
Le Mans Master
I'd check your exterior door switch pads. The exterior switch pads do have a rep for failing after some time. If one of them has developed a problem, it could occasionally make just enough contact to "wake" the system, but not long enough to actually complete the "door open" process. After few minutes, the system sleeps again.
They're easy to remove. Try removing and disconnecting one at a time and watching the drain after each.
Don't know if that's your issue, but it's quick and simple to try.
They're easy to remove. Try removing and disconnecting one at a time and watching the drain after each.
Don't know if that's your issue, but it's quick and simple to try.
Last edited by Kent1999; 04-30-2015 at 01:53 PM.
04-30-2015, 09:46 PM
#15
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St. Jude Donor '13
As cclive mentioned, there have been problems with Onstar draining the battery, I don't know the details.
04-30-2015, 09:57 PM
#16
Le Mans Master
This sounds all too familiar. Give my semi-recent thread a good read but I direct linked the post to my solved problem.
TL : DR It was a micro relay for my fog lights. I haven't replaced it (but have had it removed for the past month or so) and it hasn't died since whereas before it was a daily affair even with an Optima Yellow (deep discharge).
https://www.corvetteforum.com/forums...post1589293313
TL : DR It was a micro relay for my fog lights. I haven't replaced it (but have had it removed for the past month or so) and it hasn't died since whereas before it was a daily affair even with an Optima Yellow (deep discharge).
https://www.corvetteforum.com/forums...post1589293313
05-01-2015, 07:22 AM
#18
Le Mans Master
..It sounds like you have a pretty good grasp on how to locate a short already.. My first recommendation is try and borrow a low amp clamp from somebody if you don't have one already...
Next, I wouldn't be so quick to reinstall a fuse after you've caught an amperage drop....
Next, I wouldn't be so quick to reinstall a fuse after you've caught an amperage drop....
You're moving in the right direction working with the fuses. If you have Onstar, that would be a prime first place to start....I believe that standard clamp meters are only good for measuring AC, so a clamp won't work here. Good luck in the continuing search...
PS...don't forget the interior fuse box also...
PS...don't forget the interior fuse box also...
Now to shorten the time to find the issue. Remove ALL of the fuses and relays from both engine and interior fuse boxes. Do you still have the issue? If so it is going to be much easier to find but you know there is an issue with a fused wire which takes you to battery wiring/starter/alternator area. You can physically trace those wires because there aren't that many. If the drain is gone replace all the fuses and relays in one of the boxes. If the issue is still gone you have eliminated half the systems. Now half the fuses in the other box. You get the idea. Keep working on half the identified area at a time until you find an area that causes the issue to return. If you wait an hour for every test you should still be able to get down to one fuse in 8 hours or less rather than spend days pulling one at a time. BUT, don't think you have found the issue when you find one fuse that causes the issue when you still have others out. It might be more than one. You should keep the one you found out while continuing to replace others half at a time until you have all of them in except the ones that cause the issue.
Again, my guess is the most likely one is OnStar and would start with one fuse there just to see if that shortcut works. OnStar will come on sometimes and I don't know what the current draw is but it shouldn't stay on long and certainly shouldn't drain a battery overnight.
Good luck.
05-01-2015, 12:56 PM
#19
OnStar would be my first thought also. SOME clamp on ammeters are AC only but some are AC/DC. Yes, a DC one is needed. It would also be helpful to have one with memory so that the OP could walk away for an hour and see if anything had happened during that time.
Now to shorten the time to find the issue. Remove ALL of the fuses and relays from both engine and interior fuse boxes. Do you still have the issue? If so it is going to be much easier to find but you know there is an issue with a fused wire which takes you to battery wiring/starter/alternator area. You can physically trace those wires because there aren't that many. If the drain is gone replace all the fuses and relays in one of the boxes. If the issue is still gone you have eliminated half the systems. Now half the fuses in the other box. You get the idea. Keep working on half the identified area at a time until you find an area that causes the issue to return. If you wait an hour for every test you should still be able to get down to one fuse in 8 hours or less rather than spend days pulling one at a time. BUT, don't think you have found the issue when you find one fuse that causes the issue when you still have others out. It might be more than one. You should keep the one you found out while continuing to replace others half at a time until you have all of them in except the ones that cause the issue.
Again, my guess is the most likely one is OnStar and would start with one fuse there just to see if that shortcut works. OnStar will come on sometimes and I don't know what the current draw is but it shouldn't stay on long and certainly shouldn't drain a battery overnight.
Good luck.
05-01-2015, 02:06 PM
#20
Team Owner
Thanks. The "Battery Main 3" fuse is the main contributor to the parasitic draw, but I have no idea what's in that circuit? And when my battery is fully charged after a few hours on my battery tender, the car still doesn't want to start right up. Yesterday, while at work, I pulled the fuse. Eight hours later when I came out to leave for the evening, the car just clicked once. It did so several times. I kept pushing the starter button between start and accessory, and the solenoid finally started to click multiple times and on the eighth try the engine fired right up. It's just crazy.