Dead battery issues

[Derf]

Comments welcome...

Last Friday I used my car, came home from work, locked it, it sat all Saturday, went to go out Sunday and found car wouldn't unlock. Popped the driver door handle cover off to expose the key hole and got in, key in ignition, and nothing coming alive. OK, dead battery??

I get my girlfriend's car in front, hook up the jumper cables, MFD and radio come alive with key in ignition. Start her car, go to start my car, and all I get is clicking noises. Then errors on the MFD screen : Tire pressure monitor system error, AFS lighting error, cruise control error, brake error... bunch of errors. Car won't start.

Use my free subscription to VW-connect to ask for tech help. They say that it's the immobilizer, and that if I didn't start the car within a certain amount of time from when I unlocked it, that I am locked out. Hmmm? They send a tow truck to bring to me a dealer.

Tow truck shows up, asks what the problem is. I tell him VW thinks its the immobilizer and I need to go to the dealership. He asks if the battery was dead, I tell him yes. He pulls this little unit out from his pocket, connects it to the battery, and jumps the car no problem. I'm baffled because 1) the booster battery is no bigger than my cell phone, and 2) why didn't the jump of the car work? He says new cars use too much power with the alarm, GPS, computers, etc and that if the other car was using the battery for it's own services, there wouldn't be enough power to jump my car. What??? Basically, I can't jump a modern car anymore. HUH?

Ok, whatever.... all week I'm thinking about this dead battery. The doors locked on Friday after work, so I didn't have a door open. No lights are set to be on in the car. No cell phone left plugged into 12V outlet... So what drained the power? No idea.

I plug in my OBDEleven and see I have a bunch of error codes for all modules in the car. I reset them all. All errors are gone.

Fast forward to end of the week. Come home Friday, park the car, lock it. On Saturday afternoon I go to start it, and get the same clicking sounds as before. This time no warning on the MFD, but all the idiot lights are flashing. Then on the radio I get a warning that the 12V battery is low and almost depleted. WTF? It's now hooked up to a battery charger. Charging at 12V 2.8A (1/10 the battery capacity of 280A --- why is this battery so small?), and battery voltage shows 11.73V.

I've had the car about 9 weeks, changes include a couple tweaks via OBDEleven (mirror dip in reverse, comfort open/close windows with remote, kencha tails, ignore bulb-out warning on license plate lights) and changed the glove box, backup, and license plate light bulbs for LEDs. I moved a fuse so the 12V outlet in the armrest is always active, but I didn't have anything plugged in except a USB adapter - it has a small LED on it. I also did leave my OBDEleven device plugged in, which emits a faint orange glow, so there is a small LED there. But I wouldn't think these two LEDs are draining the battery in 24 hours.

Nothing has changed in the last week to suggest why the battery is suddenly going dead. Annoyingly it only happens on weekends when the dealerships are closed. I called the local dealer about the last dead battery and he said he needs to diagnose the problem, and can't give a firm estimate on time, but I'd have to drop the car off and leave it. Hope this would be a warranty issue.

Has anyone else had similar problems, and what did you do to solve it?




TL;DR : 8-week old GTI, battery is going dead in 24-48 hours when car isn't being used. What to do?

 

[dr_mat]

Bummer. Sounds like a faulty battery to me, but the only way to verify is to track the resting voltage as it changes changes during charge cycle. If you were down to 11.7v or so that's really only about 10% charged so no surprise it wouldn't start the car. If you know you're charging at 2.8A (fixed amperage charger?) time how long it takes for the battery to recharge to e.g. 12.4v (this should be about the top of the bulk charge cycle) and you can calculate the battery capacity from that.

BTW I doubt it's a 280Ah battery, that would be bloody enormous..

 

[golfdave]

I'd also look into fitting a bigger case size battery if you don't already have the biggest. BTW your spec of 280Ah is meaningless.

Maximum case size is 70Ah / 760A...this means a supply of 70Amps for 1hr maximum draw until the battery is drained ...Maximum supply is 760A..so 70A/hr into the 760A = 10.86hrs supply at maximum draw = totally flat, however it will register as flat way before that!

http://www.golfmk7.com/forums/showthread.php?t=7926

I would also do a scan of the BCM for the battery if you have stop/start, personally I think you have a parasitic draw on the battery & do short drives. Also se if the alternator is supplying correct "V", belt might be slipping.

 

[Derf]

Thanks GolfDave,
When this battery dies I will replace it with a larger one, but I'm not looking to do that right now.
I do happen to only drive 11 miles to work, most of it highway, so only about 15 minute commutes. That may not seem like much (5500 miles a year), but I consider myself lucky to not get stuck in traffic for 10 hours a week. Anyway, I would think that it shouldn't be an issue how I use the car, plenty of people are in similar situations, and VW should be able to design a car that doesn't go dead from how I use it.

I'm not sure where the parasitic draw comes from, but I do charge my iPhone usually as well when I drive. I think there may be an electrical gremlin somewhere, but I don't want to have to break out the DMM and start looking for it on a brand new car. Just wondering if anyone else had a similar problem that I can check something specific.

One interesting point - the "convenience consumer" info screen seems to indicate I am using a lot of resources when I have my blower set to 3 or 4, run AC or heated seats, and I assume listen to music (loud), have headlights on, etc. Which increases my fuel usage apparently. I thought the alternator, being belt driven, is a constant load on the engine, regardless of if it is only being used to recharge the battery for running spark plugs, or if it is recharging the battery that is running GPS, infotainment screen, speakers, radio, headlights, etc... If the alternator is constantly being driven by the engine, and it is supplying voltage to recharge the battery, there shouldn't be a variable fuel usage depending on how many electrical components I use... at least in my mind.

 

[dr_mat]

Nope, the increased electrical loading results in an increased resistance to rotation of the alternator and more draw from the engine.
Your usage profile is plenty to recharge the battery - mid range rpms for fifteen mins is much better than those who sit in traffic at idle for long periods.

I would say you have a parasitic drain, or a faulty battery.

 

[golfdave]

Increased electrical loading puts more strain on alternator, so the battery gets used more to fill the gap so to speak. Also It takes far longer to fully recover a battery than people think by just driving...1 to 2hrs in reality...unless you turn everything OFF..

Why do you think that certain electric heavy items are not available on the very "ECO" cars?...

Fit a bigger case size ad or a battery that can be deep cycled more & TBH VW has skimped on the sizing & fitted the one that will "just" do

 

[Derf]

So it happened again...

Drove my car on Friday home from work. It sat through Saturday until Sunday morning when I moved it in the driveway. It started right up and I only used the driver side door. Went out on Monday and the car couldn't be unlocked because the battery was dead.

Hooked it up to my girlfriend's car and unlocked the doors. Noted that the lift-gate was fully secured and all doors were closed. No accessories left on in 12V outlets. Used a pair of jumper cables to try to jump the car - the car just made a clicking noise (like a relay) but no start. Tried positive to positive, negative to negative. Tried positive to positive, negative to ground. Tried with her car running and with her car off. Left it connected for 5 minutes and tried a second time. No luck.

Called VW CarConnect for roadside assistance - a guy was sent out and he used an jump starter box to try to start the car. It looked like this.

Display showed 50% charge. He left it connected for 5 minutes and tried to jump it. No luck. Then he tried jumper cables in his trunk connected to his car's battery. Still no luck.

Made an appointment with VW dealership to get this issues addressed. Tow truck showed up to flatbed me to the dealership. I asked if he had a LiION battery jumper, and he did. One try and car started.

Got the car towed to the dealership today. Dealership said they charged the battery and battery tested good. Alternator tested good. Nothing wrong that they can find so they couldn't do any warranty work.

1) Why does my car battery randomly die? All doors are closed, no lights are on that I am aware of (but kind of dependent on doors being closed)...

2) Why can't I jump start my car from a car battery or large battery jumper?

Dealership wasn't helpful with either question.

 

[dr_mat]

Batteries that have been allowed to go flat will have a shortened life, I know that much. I would push for a replacement battery under warranty, or at the very least some diagnostic work on tracing the drain.
Agree with a previous comment that a totally flat battery needs a good drive to charge up properly, allow an hour, and possibly more if you're driving with heated seats/lights/wipers etc on. Or get it on a charger (and follow the car instructions to charge it - make sure the contact to the battery is via the charge detection circuit and doesn't bypass it. The car won't attempt to start if the charge detection still reports a flat battery).

 

[Z27]

Same thing happened to me. Bought a jump starter as big as my cellphone and the car started no problems. I then drove to the dealer to have my battery replaced under warranty. They even gave me a bigger unit.

 

[Ricked_Em]

Do you leave your OBD11 plugged in? How close do you keep your keys to your car? I've had it happen before when I left my keys in the center council and another time because I kept it right on the other side of my garage door (5ft from the car). Assuming the keys kept interacting with the car and drained it over the course of two days. I however was always able to jump it. Maybe you have some cheap cables?

 

[Derf]

I tried two sets of jumper cables, neither worked. And the guy who showed up last time had his own set he tried using. It isn't the cable's fault. I've successfully used my cables before.

The car was properly charged. These events have happened 3 times over 6 months. An intermittent but continuing problem. When it happens it seems random.

My obd11 was plugged in the last time. But- I've left it plugged in before for longer than 24 hours of non-use and it didn't kill the battery. I have since removed it and will keep it out when not in use.

My GTI is an S model - so no Kessy or key interaction with car to drain the battery.

I also bought a battery jumper as big as my cell phone. Just in case.

Dealer wouldn't replace the battery under warranty because they said they tested it and it tested "good". If it happens again I'll push for a "good faith" replacement.

 

[dr_mat]

I'd get a battery gauge in the car and make a habit of checking the resting voltage (I.e. after the car has cooled down) nightly. If you see sudden drop get in the car and start looking for active circuits/lights etc.

 

[breaking badly]

He pulls this little unit out from his pocket, connects it to the battery, and jumps the car no problem.

Just curious:
The seller claims it to deliver 10 A at 12 V. Seriously, how should just 10 A help?
To start a 2.0 T I'd say you need between 70 and 100 A at least (depends highly
on engine temp). The factory battery delivers hundreds of Amperes!

I've had the car about 9 weeks, changes include a couple tweaks via OBDEleven (mirror dip in reverse, comfort open/close windows with remote, kencha tails, ignore bulb-out warning on license plate lights) and changed the glove box, backup, and license plate light bulbs for LEDs. I moved a fuse so the 12V outlet in the armrest is always active, but I didn't have anything plugged in except a USB adapter - it has a small LED on it. I also did leave my OBDEleven device plugged in, which emits a faint orange glow, so there is a small LED there. But I wouldn't think these two LEDs are draining the battery in 24 hours.

TL;DR : 8-week old GTI, battery is going dead in 24-48 hours when car isn't being used. What to do?

Put everything back to stock and take it to the dealer. A bigger battery won't help,
since the problem is not its size, but that its either bad or somewhere there's drain.

Find the fault, don't try just curing the symptoms.

 

[Derf]

Just curious:
The seller claims it to deliver 10 A at 12 V. Seriously, how should just 10 A help?
To start a 2.0 T I'd say you need between 70 and 100 A at least (depends highly
on engine temp). The factory battery delivers hundreds of Amperes!

I can't see anywhere in the advertisement that it delivers 10 A at 12 V. One of the owners says it delivers 450 A, with a peak of 900 A. It definitely seems to be for jumping car batteries, since it comes with jumper cables. Also many people reported being useful for that purpose. Not trying to start an argument, but obviously it works to deliver hundreds of amps and start a car.

Put everything back to stock and take it to the dealer. A bigger battery won't help,
since the problem is not its size, but that its either bad or somewhere there's drain.

Find the fault, don't try just curing the symptoms.

if the dealer couldn't find a problem with my battery as is, how would changing all the VC DS settings back to stock help them find a problem with the battery?

If there is a drain, it obviously only manifests itself under certain conditions. Sometimes I can leave my car for two or three days over a weekend and not use it and it's fine on Monday. Other times I can use it on a Sunday and by Monday morning it's dead. There is definitely something strange going on, the dealer seems to think that I'm leaving the door open and the light on, although I know that I did not.

 

[dr_mat]

Something like this might help:

http://www.lascarelectronics.com/temperaturedatalogger.php?datalogger=153

Configure it to log voltage every five minutes, attach it to the battery and tie it under the bonnet. After a week or so dump the data and look for periods where the voltage drops more rapidly and then figure out what you did differently that day ..

Also, and much cheaper, look for one of those hokey red/amber/green battery condition checker units that go in the cigarette lighter socket. At the very least it'll tell you when you need to get the battery charged up so it's not going to fail on you soon.

To be honest, if you're seeing charge levels routinely drop below 60% you're going to need a new battery in pretty short order anyway.

I think my view is that you will find a constant drain, and your "leave it for two or three days and it's fine" occurs when the battery is close to fully charged, so there are no symptoms to show that it's drained... whilst the days when it fails you'll find that the battery was already low before you left it.