Battery drain issues continue

Argh I'm so frustrated with these ongoing battery drain issues. A few weeks ago I wrote about my car not starting one day. Had the battery and charging system tested and it looked fine. I hooked up the car to a tender since I wasn't driving it as often and didn't have any issues. But lately I began driving more often again. However one day last week the car would light up the dash but not turn over the engine. I jumped it and promptly went to the local parts store to buy a new battery even though the one I had was only a year old. All was good until yesterday. The new battery again lit up the dash but couldn't start the car. This was after using the car the day before and putting over 20 miles on it. I hooked it up to a charger and then today proceeded to test everything. The battery itself is now fully charged so it started the car. I tested voltage when the car was on and it was 13.6 at idle with nothing on and about 12.8 with headlights, radio, and A/C on. Running the engine brings it back up to about 13.5. So that seems fine, right? Then I disconnected the battery and wanted to check out the draw when the car was off. Right after running the car was pulling around 2.65 amps for about 10 minutes. Then this is where it gets interesting. Now when I hook up my multimeter it'll show a quick spike anywhere from 2-5 amps but then within 5 seconds drops down to a steady 0.01 draw. Is this normal? From that point it will stay at 0.01 amps until I disconnect the clamps. When I reconnect it again spikes for a short period of time and goes back down to 0.01 So WTF can I deduce from this? Based on what I'm seeing the battery should NOT be draining so quickly. Sure I have quite a draw when I first stop using it but from that point on the draw is pretty low. Is the spike when I reconnect something to be concerned about? After starting the car if I do for an extended drive the battery does charge so I think the alternator should be fine. But something, somewhere is killing my battery and I can't figure out what or how to track it down since the draw ends up being minimal after I begin testing it. Any ideas? Help!

Make sure the grounds, one in the frunk and one on the engine are clean with absolutely no corrosion. Not sure about the spike in amps...but what happens when you lock the car? When you shut down, get out and close the door the DME remains in ready mode. However when you lock the car it goes to sleep (in a manner of speaking). Also, are any of the lamps staying lit? Frunk and engine lid light come to mind. Also, it could be a problem with your alternator. Maybe an old voltage regulator on it's way out. Electrical problems are a PITA to figure out. Just my suggestions on where to start.

Quotes source post: 12602625

Technically OK, but right about 14 with the engine running would be better. Maybe the stator is starting to go in the alternator? I don't understand. You disconnected the battery while the car was running? If so thats a big no no on modern cars as it can damage the electronics. If the car was off and you disconnected the battery, there wouldn't be any draw to measure... When you are "hooking" it back up, what was the state of the car up to that point? Did you have to unlock it? Open the hood? Open a door? Use the remote? etc.. I haven't checked the 996 and I don't hear anything from it, but I know both the Cayenne and BMW continue to run things for awhile after you shut them down. They eventually go to sleep, but as soon as you disturb them (open a door, etc..) they wake up some stuff even before you put the key in the ignition. Could be that the 996 does some of the same stuff. I'll try to remember to take my ammeter out in an hour or so and get some readings of ours for you and see what I get.

Quotes source post: 12602728

Thanks for the quick response. Grounds are pretty clean as I don't see any corrosion anywhere. Alternator is about 4 years old but as appears to be charging okay. Plus wouldn't the ground or bad alternator show up on my voltmeter as excessive draw or low voltage? I suspected the frunk light early in the process so I recorded a video on my cell phone and found that it does turn off once I close the lid. As for what it does when I lock the door. In that case the spike is at about 0.35 A and then it goes down to 0.01 A as it was doing before. Thanks again for the suggestions.

Quotes source post: 12602787

There are two important parts of the alternator. The voltage regulator and the stator. The first is what will show up on your volt meter and if it is going bad you will see wild fluctuations and going outside of the normal 13.5-14.5 range. The stator impacts the amperage that is being put out under different loads and it is typically diagnosed by measuring its output with an ammeter at various RPMs. If your stator is putting out less amps that your system draws, it can't charge the battery and the battery runs down. Unfortunately the age of the alternator isn't a great indication, especially if you have an issue somewhere else in the system (e.g. short). I went through 4 high output (250A!) alternators in 18 months in my old Escape where the stator kept frying on me. I had a short somewhere in all the extra gear I had installed, but I never found it

You can always start pulling fuses in the different groups(locking system, radio, lights, etc) and observe the voltage again.

I smell a short somewhere.... Like Alpi says, start with an elimination process and one by one rule out different things. Of course, this also has its limitations.

The whole problem I'm having with diagnosing this is that once the leads are hooked up for more than 5 seconds the draw drops down to 0.01 amps. If it would remain constant then removing fuses would be great for troubleshooting because then I can figure out what is pulling the amperage. Just stumped as to what I can do aside from taking it to the dealer for service. I don't think it's the alternator because I can jump the car, come back from a 30 minute drive, and test the battery and it does show it is fully charged. Unless the alternator can pull from the battery when the car is off and I can't spot that on my multimeter?

So this is what I found with our 01 C4 coupe: Came out, unlocked it, opened a door, popped the hood, and connected the ammeter to the negative cable: At 5 minutes the the frunk light is still on and it's been reading between 1.77A and 1.82A and mostly at 1.80. At 7 minutes it's falling off and around 1.73A now. Does the frunk light timeout? 10 minutes and it is still 1.72A with the light on. Battery is a steady 12.53V. Locked car with the hood open: Jumped to 4 point something and then dropped back to 1.8A after the "hood is open still" beep. 5 min = 1.74A 10 min = the frunk light finally went out and it's reading 0.18A Unlocking Caused a jump to 11A, hung at 4.2A for about 30 seconds, then back to 1.8A. Open doors and engine bay = 4.2A Ignition on (no crank) with AC and stereo off: 8.35A Lights, stereo, AC, defroster, and seat heaters: 63.2A Engine running with everything on: Idle: 5-9A in the hole 2k: 16-20A charging 3k: 16-20k charging All acc off: Idle: 25A charging 2k: 23A charging 3k: 23A charging I forgot to get another reading (my wife came out demanding to know what I was doing to her car and distracted me), but at idle with everything on the volts were reading under 13. This makes sense as it was still discharging under that load. The dash volt meter went up to about 14 when I came off idle and when I turned everything off at idle. When I connected the ammeter (clamp style), I did see a spike like you mentioned. I think that is just an effect of the Hall effect sensor. Of note is that we have an aftermarket stereo with 2 amps so our "everything on" will be higher than usual. Hopefully that gives you a baseline to check yours against.

Quotes source post: 12603097

If I removed the guts of my wife's car and gold-plated it, she would be just as suspicious.

Well played sir. Well played In reality it has more to do with the mess I made of my Escape's electrical system...

Quotes source post: 12603149

Don't be too hard on yourself bud. After all, it was an Escape.

It does not sound like your alternator or charging system has faults. 0.01 amps after a few minutes....it doesn't really get any lower than that. There is a large draw that is happening when you are not measuring that is drawing the battery down, or your Y cable is causing it not to start. When the car won't start, what is the battery voltage before you charge it?

Quotes source post: 12603235

Hey! Other than the alternator I loved that car. First car I had more than 3 years. Replaced it with the 958d and I still get misty every time I see it (gave it to her dad).

The spike is normal (DME and other electronic modules restart). 12.8v with load at idle sounds like bad alternator or the "y" cable to me. Normal is 13.5 to 14.5 at all times with load even at idle. To diagnose it properly, you need to perform volt drop test to see where you lose the voltage. When it doesnt start, are you sure its the battery and its not something else like your clutch switch?

Quotes source posts: 12603097, 12603245, 12603430

Thanks! This will serve as a good baseline for my testing tomorrow. Going to try again after letting the battery sit on the trickle charger throughout the night. Would the Y cable though cause drainage without registering on my multimeter though? As for the battery voltage, today when I tried it, it came up at around 11.8. I then charged the battery for about 30 minutes and started the car right up. Most of what I read did say that just below 13 is normal at idle with a full load. That also aligns with what gnat said above. Is that not the case? I probably really need to check this Y cable since it seems to be the one part I really haven't looked at very closely in my troubleshooting. I just found this link referring to it, should I follow these steps? http://www.renntech.org/forums/topic...tage/?p=240055 I'm pretty sure this is battery related as when I turn the key I get the "click-click-click" that happens when you don't have enough juice. I can then start the car immediately if I jump it. If it were the clutch switch I would probably have full lighting on the dash but just no start. I've also ruled out the ignition switch as a few years that went bad on me and the symptoms were very different. Thanks again everyone. I'll report back tomorrow what I find!

Its always the Y cable. It will look spanking new when you take a look at it but it will be the problem.

Yes, thats my post on Renntech that you can follow. You said idle with a/c, headlight (low beam I assumed) and radio on, you got 12.8v. If the measurement is accurate, thats 0.7v lower than spec and thats not enough to charge the battery well.

So to test the corroded cable theory I sprayed some WD40 on the jumper terminal in the engine bay. Right after I did that I was getting a reading of 14.4 volts at the battery! I went for a 30 minute drive and throughout the trip the voltmeter steadily went down until I arrived home at which time it read 13.3. Unfortunately when I turned on lights, A/C, and radio it was down to 12.8. I tried spraying more WD40 on the positive terminal but this time it didn't seem to make a difference. So does that sound like the Y cable?

I had similar problem - bad alternator diodes - if you leave the car overnight, is the alternator warm ? Battery will drain back through the diodes to ground - I removed and had my alternator rebuilt - fixed the problem - of course it could be another circuit causing excessive drain - but you will only see the drain in the battery positive cable (I used clamp type multimeter) if diodes are bad ....

Quotes source post: 12604707

No factory sized alternator will charge the battery at idle while under full load. It used to be that you had to have your RPMs fairly high (4k) to get your peak output, but it appears from my test yesterday that these peak pretty quickly. fpena, no idea about the WD40 trick. Never heard of or tried it before.

Quotes source post: 12605027

Im not sure if you are agreeing with me or not but just to be clear, I said low beam + a/c + radio, which will be about 65A total load, no where near the peak output, which is about 120A. All Im saying is 12.8v under that condition is out of spec so something is wrong.

I also think it could be Diodes. What amp reading do you get measuring amps on the positive side of the battery with ignition off? I suspect the WD 40 trick might be a red herring? That doesn't mean you can't have 2 problems with one being a high resistance Y cable.

Quotes source post: 12605092

Nope, disagreeing At idle the alternator doesn't put out enough Amps to cover that load so the battery is doing most of the leg work. That's why you can see such a voltage drop in such a situation. Once you get the RPMs up high enough that the alternator can meet the demand you then see the higher voltage of the alternator.

Quotes source post: 12605305

Put an amp clamp around the battery cable under such condition and see you what you find if your battery is discharging, you have a problem.

Quotes source post: 12605324

I did, those are my numbers. I've also worked with the electrical systems of plenty of other cars. No factory spec alternator for at least the last 25 years puts out enough amps at idle speed to cover a full electrical load. Alternators do not put out a fixed current at all speeds. The rated size of an alternator is at a specific engine speed. In this case it appears that 2k seems to be the magic engine speed for the peak output. Honestly I'm surprised that it appears that we have a 90A alternator with a peak load around 65A. Most cars are built with only a 10% buffer anymore.

Quotes source post: 12605344

I only saw your measurement of "everything ON" and I don't see any measuremts with only a/c+low beam, which is what I've been talking about. Understood the spec is at a specified rpm but with only a/c and low beam, those should not discharge your battery at idle if your system is working correctly and that's my point.

Quotes source post: 12604931

I don't know what effect WD40 would have, but a corroded cable will sometimes function normally when the engine is cold and progressively get worse as the engine bay heats up. If you decide to change the cable, make sure you use the new technique of using hot water to remove the plastic box on the new cable. This will eliminate the need to loosen the AC compressor or move the steering pump tube.

Quotes source post: 12604957

+1 The alternator was warm to the touch even after teh car sat overnight.

Alternator was room temperature when I checked it this morning.

Dc current clamps are very affordable now. It can track that alternator drain instantly by clamping the power supply cable inside the engine bay. If you put it around one of the battery cables, it will show you if the battery is currently being charged or if its draining. This avoids disconnecting the battery, which can cause whatever drain condition to go away (undetectable) as eletronic modules get reset when power is reconnected. http://www.amazon.com/gp/aw/d/B00O0H...JvL&ref=plSrch

This car is wacky... I'm back to commuting now and almost the entire drive the voltmeter is at or around 14 volts. So I've had no issues for the past few days. I'm still going to have the dealer check it out when I get my track inspection done but just another piece to the puzzle.

14v doesn't mean you don't have diode problem - my battery was charging fine - it was just when the car was shut off it was draining in a few days and then finally overnight as diodes degraded

I always recommend this handy and extremely accurate tool for ppl to monitor the battery. It uses only 7mA so it's save to leave it plugged in overnight. Amazon.com: INNOVA 3721 Battery and Charging System Monitor: Automotive Amazon.com: INNOVA 3721 Battery and Charging System Monitor: Automotive Various readings under different conditions will tell you a lot about how well your charging system is working. Before you unlock the door in the morning, take a peek through the windows. The battery should be around 12.5v. If not, your battery is not fully charged. When cranking, it should show 9-10v. When driving, it should be around 13.3v- 14.2v with moderate load such as a/c and low beam ON.

Just wanted to provide closure for this thread... I took my car into the dealer today for a track inspection and asked them to check out the charging system. They tested the alternator, battery, and all of the bits and pieces in between. What they found was that everything was working as it should. So I asked what the problem has been? They said it was because I hadn't been driving it enough. Now since I've been using the car again on a daily basis I've had no issues but I'm still going to keep my eye out. Anyway I guess problem solved...for now!

Another reason to drive our cars more

Quotes source posts: 12637412, 12481397

If only someone had suggested that to you sooner... Glad it's playing nice for you again.

Quotes source post: 12638197

I really thought I had crossed the threshold of what is considered a long drive. I guess not! But yeah you were right. Just for reference my commute now is about 22 miles so plenty of time to charge. While when I was not commuting it would sit for a couple of days then go for a 5 mile drive, head back, and park again for 2-3 days. I have my trickle charger set up now though so if I get into that situation again I'll make sure to use it. And I got really good at using my multimeter and bought a better battery out of the whole deal. So I guess a win on all fronts! But what do the city guys do? If your car is parked in NYC or SFO you can't hook up a trickle charger and it's not likely you'll drive 5 miles at any point in time. So how do they survive?

Quotes source post: 12638385

Just poking fun That it's working is the important part. That you got to buy new tools and learned something is a bonus