Dead Battery after two weeks -- Is this too much draw?
11-07-2015, 02:54 PM
#1
Racer
Thread Starter
Dead Battery after two weeks -- Is this too much draw?
Hey guys,
I'm regularly away from home two weeks at a time and recently (last 1.5 months) have come home to a pretty much completely dead car. My FOB won't even register for unlocking/locking. I have a trickle charger but I haven't been using it since I replaced my battery with an Optima Red Top last September. I checked the draw across the battery after the computer shut down and the first time it had evened out to about 35 milliamps and now it's showing 60 milliamps. I've found that it should be pulling maybe 15-20 max. Is that enough draw to cause an issue? I pulled every fuse in the under-the-hood fuse box and never saw a change in draw, so perhaps my voltmeter is just not super accurate. Anyone have any thoughts on the subject? A jump start gets it going fairly quickly and it usually lasts for my two weeks at home (starting once a day or every other day) until I leave for two weeks then its dead again.
I'm regularly away from home two weeks at a time and recently (last 1.5 months) have come home to a pretty much completely dead car. My FOB won't even register for unlocking/locking. I have a trickle charger but I haven't been using it since I replaced my battery with an Optima Red Top last September. I checked the draw across the battery after the computer shut down and the first time it had evened out to about 35 milliamps and now it's showing 60 milliamps. I've found that it should be pulling maybe 15-20 max. Is that enough draw to cause an issue? I pulled every fuse in the under-the-hood fuse box and never saw a change in draw, so perhaps my voltmeter is just not super accurate. Anyone have any thoughts on the subject? A jump start gets it going fairly quickly and it usually lasts for my two weeks at home (starting once a day or every other day) until I leave for two weeks then its dead again.
11-07-2015, 04:18 PM
#3
Melting Slicks
I found out the hard way that Optima's don't like to sit. I got 2-3 weeks on the Red Top before it died. (same story, charged it up and it was fine) I replaced it after 5 years with a Yellow Top and it isn't much better. About this time of the year I hook up the tender as the snow keeps the Vette trapped in the garage.
11-07-2015, 04:32 PM
#4
Team Owner
Have you checked the obvious things like an interior lamp left on? Maybe the underhood light is not shutting off because of a bad timer.
I had a current draw issue with my '02 where a relay for the seat adjustment was sticking. I kept hearing an occasional click and a buzz. Swapped out the relay and the draw went away.
I have never been a fan of the Optima batteries, There were some problems with the Red Top version a few years ago. The Yellow Top is a good deep-cycle battery but IMHO, that type of battery is not really for automotive use.
I do use a Deltran Battery Tender Junior on my '02 but the car pretty much sits during the winter months. I have Interstate batteries in both my C5 and C4 and the C4 can sit for 3 months and still start.
From everything I have read, a C5 battery will be discharged if it sits in the car for about a month. Just enough draw from all the microprocessors and computers that it takes that amount of time to bring the battery down to where the battery doesn't have enough power to start the engine.
I had a current draw issue with my '02 where a relay for the seat adjustment was sticking. I kept hearing an occasional click and a buzz. Swapped out the relay and the draw went away.
I have never been a fan of the Optima batteries, There were some problems with the Red Top version a few years ago. The Yellow Top is a good deep-cycle battery but IMHO, that type of battery is not really for automotive use.
I do use a Deltran Battery Tender Junior on my '02 but the car pretty much sits during the winter months. I have Interstate batteries in both my C5 and C4 and the C4 can sit for 3 months and still start.
From everything I have read, a C5 battery will be discharged if it sits in the car for about a month. Just enough draw from all the microprocessors and computers that it takes that amount of time to bring the battery down to where the battery doesn't have enough power to start the engine.
11-07-2015, 05:32 PM
#5
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The C5 does drain a battery fairly fast if you just let it sit. Use a battery tender when you're not driving it and you won't have to worry about having a dead battery when you do want to drive the car.
11-07-2015, 07:02 PM
#6
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I keep some kind of float charger on my car at all times unless driving it. Red tops do NOT like to sit and a C5 will kill pretty much any battery pretty quickly.
You can get a nice little float charger at Wal Mart for around $20 that works fine. If your Red top goes dead, TRICKLE charge it overnight at 2a or less. They don't like to be quick charged from dead and you will shorten it's life quickly.
You can get a nice little float charger at Wal Mart for around $20 that works fine. If your Red top goes dead, TRICKLE charge it overnight at 2a or less. They don't like to be quick charged from dead and you will shorten it's life quickly.
11-08-2015, 12:48 AM
#7
Burning Brakes
I never have any issues with mine. I just got home from an 18 day vacation and it starts up like it was running the night before. I've had it sitting for much longer periods when I'm doing work on it with no issues either.
11-08-2015, 07:34 AM
#9
Le Mans Master
You have a parasitic drain if you are at 60 milliamps. A tender is just a band aid.
Here is some info. Let me know if I need to clarify anything of if I can help in any way.
Suggest you remove the hood light bulb first so it does not provide a drain.
For measuring battery drain I would hook up an ammeter to the negative side of the battery by removing the negative cable and measure between the cable and the negative battery post.
When you connect the ammeter the car should draw several amps until it goes into "sleep" mode which can take several minutes. Normal sleep mode drain should be 30 milliamps or less by GM standards. You will need an ammeter that can transition from whatever the drain is down into the sleep mode. If you have a drain I suggest the following:
Once you determine you have a drain with an ammeter what I recommend first is to listen to each fuse box and see if you hear any relays operating. If not, then place your hand on each relay to see if any of them feel hot. That can be the start if you find something like that is happening.
If nothing shows up you can hear or feel then I recommend you separate the two fuse boxes from each other. This is easy and done by removing the Red cable from the engine fuse box that feeds the passenger fuse box. It is on the right rear side of the engine fuse box. There is a stud there where the large Red wire from the battery connects. Just remove the nut and disconnect the large Red wire feeding the passenger fuse box and reattach the Red battery cable. NOTE: I would recommend disconnecting the negative ammeter hookup when working on the positive side doing this.
What you will be doing is measuring the drain with an ammeter to see if disconnecting the passenger fuse box causes the drain to go away or not. By depowering the passenger fuse box you will depower the BCM which controls the sleep mode so do not expect the sleep mode to happen.
If removing the feed to the passenger fuse box you then see you have eliminated the drain then you know it is something related to those circuits. If it does not reduce the drain then you know it is related to the engine fuse box. It could be a rare case where you have some drain via both fuse boxes and we can deal with that if you think it is the case.
Just so you know, even though it may appear to be a problem in the engine or interior area the fuse boxes do feed circuits to each other that are not affected by separating the boxes. So, separating the fuses boxes can tell you how to narrow down your search but still not where the issue may be. That is where the schematics come into play to track down the “real” culprit. Hope that makes sense.
Once you basically know where it is then you can remove fuses and relays to see where the drain is coming from.
PS: There are cases where the alternator causes a drain so it can be disconnected and see if the drain drops.
Mr. Sam
Here is some info. Let me know if I need to clarify anything of if I can help in any way.
Suggest you remove the hood light bulb first so it does not provide a drain.
For measuring battery drain I would hook up an ammeter to the negative side of the battery by removing the negative cable and measure between the cable and the negative battery post.
When you connect the ammeter the car should draw several amps until it goes into "sleep" mode which can take several minutes. Normal sleep mode drain should be 30 milliamps or less by GM standards. You will need an ammeter that can transition from whatever the drain is down into the sleep mode. If you have a drain I suggest the following:
Once you determine you have a drain with an ammeter what I recommend first is to listen to each fuse box and see if you hear any relays operating. If not, then place your hand on each relay to see if any of them feel hot. That can be the start if you find something like that is happening.
If nothing shows up you can hear or feel then I recommend you separate the two fuse boxes from each other. This is easy and done by removing the Red cable from the engine fuse box that feeds the passenger fuse box. It is on the right rear side of the engine fuse box. There is a stud there where the large Red wire from the battery connects. Just remove the nut and disconnect the large Red wire feeding the passenger fuse box and reattach the Red battery cable. NOTE: I would recommend disconnecting the negative ammeter hookup when working on the positive side doing this.
What you will be doing is measuring the drain with an ammeter to see if disconnecting the passenger fuse box causes the drain to go away or not. By depowering the passenger fuse box you will depower the BCM which controls the sleep mode so do not expect the sleep mode to happen.
If removing the feed to the passenger fuse box you then see you have eliminated the drain then you know it is something related to those circuits. If it does not reduce the drain then you know it is related to the engine fuse box. It could be a rare case where you have some drain via both fuse boxes and we can deal with that if you think it is the case.
Just so you know, even though it may appear to be a problem in the engine or interior area the fuse boxes do feed circuits to each other that are not affected by separating the boxes. So, separating the fuses boxes can tell you how to narrow down your search but still not where the issue may be. That is where the schematics come into play to track down the “real” culprit. Hope that makes sense.
Once you basically know where it is then you can remove fuses and relays to see where the drain is coming from.
PS: There are cases where the alternator causes a drain so it can be disconnected and see if the drain drops.
Mr. Sam