Looking for an answer to this question, a number
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Looking for an answer to this question, a number
A search through the archives shows many owners reporting that C6s are tough on batteries. I am wondering what a typical current draw is on these cars in milliamps...
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Ok, so that is ideal but surely we should be able to get measurements from C6 owners and maybe get some kind of average value. I'll take the first shot, it's not a good one, 400 mA and I know I have a problem but what is realistic to shoot for, 25 mA?
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That computation is good for ANY car…is yours is 400 mA’s it time to start diagnosing !!…so what is the RC of your battery ??
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It's 100. I did that voltage drop test across fuses and pretty much came up empty, my electrical engineer friends are skeptical about that test method fwiw. Yeah I am going to have to dig deeper for sure.
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What test method ???…the RC divided by 4 ??…an electrical engineer wouldn’t know that !!…an automotive diagnostician will.
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Sorry, no not that calculation. The test I'm referring to is to measure the voltage drop across a fuse, someone posted a Youtube link about that in another thread. You measure the small voltage drop across a fuse and then read the current off of a chart. I got nothing but zeroes when I tried that although I did get a reading off the Courtesy Light fuse with the lights on. I guess the next step is to pull fuses and take current readings although the Youtube guy says if you do that you may inadvertently energize certain systems and get faulty readings. If anyone has been down this road I would love to hear what came out of it.
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Sorry, no not that calculation. The test I'm referring to is to measure the voltage drop across a fuse, someone posted a Youtube link about that in another thread. You measure the small voltage drop across a fuse and then read the current off of a chart. I got nothing but zeroes when I tried that although I did get a reading off the Courtesy Light fuse with the lights on. I guess the next step is to pull fuses and take current readings although the Youtube guy says if you do that you may inadvertently energize certain systems and get faulty readings. If anyone has been down this road I would love to hear what came out of it.
Yes, if you pull fuses you may wake up a module and the draw may actually increase.…try removing the B+ cable off the alternator…a bad alternator diode can cause a battery drain…you can try removing relays while you have the DVOM in series with the positive or negative battery cable reading AMPS…are you taking your readings after the modules go to sleep…around 20-30 minutes ??
Last edited by C5 Diag; Apr 20, 2023 at 08:47 PM.
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Yes, if you pull fuses you may wake up a module and the draw may actually increase.…try removing the B+ cable off the alternator…a bad alternator diode can cause a battery drain…you can try removing relays while you have the DVOM in series with the positive or negative battery cable reading AMPS.
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Just to make sure, you are saying check the current at the battery with the B+ disconnected at the alternator? I can do that. As for relays I have been wondering about those too, so if it works to pull them and see what that does to the current I can do that too. Thanks...
Last edited by C5 Diag; Apr 20, 2023 at 09:32 PM.
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Yes, C5’s and C6’s about 30 minutes…just wait for the current draw to stabilize…you want to make sure you have a fully charged battery of 12.66 volts when you start your testing…good luck !!
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Well maybe improvement or it wasn't as bad as I thought. Disconnecting the alternator had no effect but after reconnecting it the readings I got were much lower, around 70 mA and I don't know what is different. Maybe there were some lights on that I didn't see or something else was not shut down causing the 400 mA readings. Still higher than 25 but I think for now I'm going to keep an eye on it and see if the battery holds a charge. I did get it tested and it checked out good. Fingers crossed...
Last edited by Jim__H; Apr 21, 2023 at 06:59 PM.
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Yes, and it a two part answer.
The first is the alternator in the car, and it not able to keep up with the demand sitting at stop light with the A/C on. so during this time, it draining the battery down, and until you start to move again at say 2K RPM's, the battery is not being fully charged up again. So solution for this way, is 170 amp billet 6 pole alternator, that puts out over 45 amps when the motor is idling, verses the oem 3 pole unit that puts out less than 20 amps at idle instead.
The second part, is that car puts the modules into sleep mode, so even with the car off, its still pulling power from the battery to drain it down (is some cases, battery will only last about 3 weeks before it too low to start the car on it's own. So run of thumb, if you are not driving the car for a say 3 days or more, get it on the battery tender to keep the battery topped off.
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[QUOTE=Dano523;1606541543]Yes, and it a two part answer.
The second part, is that car puts the modules into sleep mode, so even with the car off, its still pulling power from the battery to drain it down (is some cases, battery will only last about 3 weeks before it too low to start the car on it's own. /QUOTE]
Have you ever measured that? I'm kind of surprised that no one has any readings that they have taken to throw into the conversation.
But yes, I think I'll buy a Battery Tender, my trickle charger doesn't have a maintenance mode.
The second part, is that car puts the modules into sleep mode, so even with the car off, its still pulling power from the battery to drain it down (is some cases, battery will only last about 3 weeks before it too low to start the car on it's own. /QUOTE]
Have you ever measured that? I'm kind of surprised that no one has any readings that they have taken to throw into the conversation.
But yes, I think I'll buy a Battery Tender, my trickle charger doesn't have a maintenance mode.
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Very easy to measure, and just wire a multi-meter between the battery positive cable, and the engine fuse box with the meter set to amps ( aligator clips work very well, since you can disconnect the engine fuse box terminal, clip on onto it, and then clip to the engine fuse box terminal so all the voltage/amperage is going through the meter. .
So long as you don't try to start the car, amps will be under the 10 amp rating of most multi meters and can watch as the modules go into sleep mode, ending up in the end of about a .175amp draw on the battery in the end. So should be over 1 amp to start with with the car into run mode/motor off, then turn the car off, open the door to get out and close the door, and withing a few mins with the car untouched, should be down to about .175amps on the meter.
Note, if you touch the door pull buttons, or push the lock or unlock buttons on the fob, it's going to wake up the BCM and RCDLR, so would have to wait for them to go back into sleep mode again.
So long as you don't try to start the car, amps will be under the 10 amp rating of most multi meters and can watch as the modules go into sleep mode, ending up in the end of about a .175amp draw on the battery in the end. So should be over 1 amp to start with with the car into run mode/motor off, then turn the car off, open the door to get out and close the door, and withing a few mins with the car untouched, should be down to about .175amps on the meter.
Note, if you touch the door pull buttons, or push the lock or unlock buttons on the fob, it's going to wake up the BCM and RCDLR, so would have to wait for them to go back into sleep mode again.
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Very easy to measure, and just wire a multi-meter between the battery positive cable, and the engine fuse box with the meter set to amps ( aligator clips work very well, since you can disconnect the engine fuse box terminal, clip on onto it, and then clip to the engine fuse box terminal so all the voltage/amperage is going through the meter. .
So long as you don't try to start the car, amps will be under the 10 amp rating of most multi meters and can watch as the modules go into sleep mode, ending up in the end of about a .175amp draw on the battery in the end. So should be over 1 amp to start with with the car into run mode/motor off, then turn the car off, open the door to get out and close the door, and withing a few mins with the car untouched, should be down to about .175amps on the meter.
Note, if you touch the door pull buttons, or push the lock or unlock buttons on the fob, it's going to wake up the BCM and RCDLR, so would have to wait for them to go back into sleep mode again.
So long as you don't try to start the car, amps will be under the 10 amp rating of most multi meters and can watch as the modules go into sleep mode, ending up in the end of about a .175amp draw on the battery in the end. So should be over 1 amp to start with with the car into run mode/motor off, then turn the car off, open the door to get out and close the door, and withing a few mins with the car untouched, should be down to about .175amps on the meter.
Note, if you touch the door pull buttons, or push the lock or unlock buttons on the fob, it's going to wake up the BCM and RCDLR, so would have to wait for them to go back into sleep mode again.
Reading some old forum threads it looks like the door or rear hatch latches can be problematic and that 25 mA is the target to shoot for. So I suppose I can test those by opening the right door, pulling the fuse, closing the door, and waiting an hour to take a reading? And if that is not it keep repeating the process with different fuses until something shows up?
The Battery Tender should show up today.
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Make sure you aren't bringing a key fob anywhere near the car when you're testing current drain. A fob will "wake up" some of the electronics modules as well.
You won't get a C6 down to 25ma. IIRC, when I worked at a dealership back when these cars were new, the GM service info (manual or TSB) said "under 200mA" was "acceptable."
Oh, and "fob near car" can cause drain issues. We had one customer who parked in the garage, and the garage wall next to the car had the master bedroom on the other side. He put his keys on the dresser that was against that wall in the bedroom, and the car stayed "awake" all night. You have to keep the key (fob) away from the car when it's parked.
You won't get a C6 down to 25ma. IIRC, when I worked at a dealership back when these cars were new, the GM service info (manual or TSB) said "under 200mA" was "acceptable."
Oh, and "fob near car" can cause drain issues. We had one customer who parked in the garage, and the garage wall next to the car had the master bedroom on the other side. He put his keys on the dresser that was against that wall in the bedroom, and the car stayed "awake" all night. You have to keep the key (fob) away from the car when it's parked.
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Make sure you aren't bringing a key fob anywhere near the car when you're testing current drain. A fob will "wake up" some of the electronics modules as well.
You won't get a C6 down to 25ma. IIRC, when I worked at a dealership back when these cars were new, the GM service info (manual or TSB) said "under 200mA" was "acceptable."
Oh, and "fob near car" can cause drain issues. We had one customer who parked in the garage, and the garage wall next to the car had the master bedroom on the other side. He put his keys on the dresser that was against that wall in the bedroom, and the car stayed "awake" all night. You have to keep the key (fob) away from the car when it's parked.
You won't get a C6 down to 25ma. IIRC, when I worked at a dealership back when these cars were new, the GM service info (manual or TSB) said "under 200mA" was "acceptable."
Oh, and "fob near car" can cause drain issues. We had one customer who parked in the garage, and the garage wall next to the car had the master bedroom on the other side. He put his keys on the dresser that was against that wall in the bedroom, and the car stayed "awake" all night. You have to keep the key (fob) away from the car when it's parked.
Guys, thanks for the input. I hope this all helps someone else as well.
Last edited by Jim__H; Apr 24, 2023 at 02:31 PM.
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From: Cape Coral, Florida
Make sure you aren't bringing a key fob anywhere near the car when you're testing current drain. A fob will "wake up" some of the electronics modules as well.
You won't get a C6 down to 25ma. IIRC, when I worked at a dealership back when these cars were new, the GM service info (manual or TSB) said "under 200mA" was "acceptable."
Oh, and "fob near car" can cause drain issues. We had one customer who parked in the garage, and the garage wall next to the car had the master bedroom on the other side. He put his keys on the dresser that was against that wall in the bedroom, and the car stayed "awake" all night. You have to keep the key (fob) away from the car when it's parked.
You won't get a C6 down to 25ma. IIRC, when I worked at a dealership back when these cars were new, the GM service info (manual or TSB) said "under 200mA" was "acceptable."
Oh, and "fob near car" can cause drain issues. We had one customer who parked in the garage, and the garage wall next to the car had the master bedroom on the other side. He put his keys on the dresser that was against that wall in the bedroom, and the car stayed "awake" all night. You have to keep the key (fob) away from the car when it's parked.
