Electrial Drain "Porsche Boxster 986" Electrical drain

[850dunstall]

yeah 16 yr old stud on a first date....., and they usually don't get lucky.

so what happened?

[RadioDjKev]

It started right up! The battery was still full charged after sitting 20 hours
with battery connected, but with the starter dis-connected.

However I think my alternator was also disconnected because the cable at
terminal 30 that I dis-connected had 2 wires in it, one go's to starter, the
other go's to alternator.

With this cable disconnected my starter solenoid would still click if I turn the
key. So I wonder if that rules out the starter solenoid.

So it's down to the Starter or alternator..both are original at 101k miles
and 9 years old.

[eki912]

Since you already located that #30, with 2 wires going down, what if you take off those 2 wires ? One at a time ? One goes to starter , right ? The other to the alternator?
Leave them loose, one at a time for one night, and see what happens.

BTW: If there is a current draw that big running through either of those wires, you should get a spark when disconnecting/connecting.If battery is connected.
Be careful.

[RadioDjKev]

So 2 days ago when I disconnected terminal 30, the battery did not drain. I am sure
terminal 30 disconnected the Alt and Batt. ok,
Then last night I disconnected the starter main cable directly at the starter,
leaving terminal 30 connected and batt connected, because the direct connection to
the Alternator was to difficult to get at.
So I feel that I left the Alt connected and the starter disconnected so the battery
should be dead in morning. Well it was not, it seemed fully charged and it started right up.

[JMatta]

Sounds like the starter is the culprit after all.

[eki912]

While doing some electrical work myself, I was looking inside my toolbox, and found my clamp ammeter !
That is one thing that you could try too ?

That place you have disconnected , that has one heavy cable coming, and two leaving, to alternator & starter.You could test both those wires, easily safely & fast with a clamp ammeter.
The same clamp could be used at the battery side.One wire at a time.It shouldn't show much amps at all, when everything is turned off.

You put one wire at a time, inside the clamp claws.It should show/measure the current running through that wire.
Test those two wires going to alternator & starter.If you have significant reading on either one, follow that wire, to where ever it goes, to pinpoint the culprit?

I haven't used clamp ammeter myself, on a car, but it should work ?
On A measurement & DC side.

Or am I wrong ????

[Paul Stewart]

That would work fine, and is exactly what I would use in this case.

[RadioDjKev]

I think it is the starter draining the battery by way of a bad starter solinoid.
I also think this starter solinoid became shorted out from the clutch pedal safty switch. Many times when I was in the middle of turning the starter my lazy foot would let up too much on the clutch and it would shut off the stater in the middle of a start up. Many times this happend. soon after the drain started that I have traced to the starter. Well being unemployed I do not have even have the cash to buy a stater. And they are not much at all. $262.00 at the Porsche Dealer.
Thanks, Kevin

[daves944]

I bumped into this thread while searching for a resolution to exactly the same problem. After a couple weeks of head scratching, the problem turned out to be a bad...but good alternator. Even thought the alternator was charging, it was also shorted internally and draining the battery down when the car sat for awhile. I now have a new ignition switch, that didn't fix the problem, a new battery out of desperation, and finally a new ebay alternator that was the real culprit initially. I hope this helps someone as this seems to be a fairly common problem.

[Wayne 962]

Cool, thanks for the tip. I've heard of that happening before on other cars, but not the Boxster. The alternator can typically be tested at a shop when you remove it from the car.

-Wayne

[oboxster]

Thanks to this thread (and a few others I'm sure) I was able to eventually trace and fix a parasitic drain on our 986's battery. Here's the blow-by-blow in hopes it might help someone else out:

1998 986 - 96k
Problem: The car sits for two days and battery is drained. Responds to charging, seems to be fine when driven daily, though the starter can seem a bit sluggish (might be my imagination). Battery is Sears Diehard about 6 months old.

Steps taken:
* took it to Sears, battery and alternator check out fine.

* replaced ignition switch (in this case, the whole unit including the steering wheel lock, also replaced the turn signal assembly on the steering column because the turn signals were not canceling, but that's another story...)

* checked all the fused circuits with ammeter, noting that the static draw was ~3A (!!!). None of the pulled fuses made a difference, though B-1 (inst cluster) was a little weird in that putting it back in caused a momentary jump in the current, which then went back down. (I also noticed a clock-like ticking under the dash that started off periodic, then intermittent, then gone - no idea what that was.) At any rate, this is starting to make big sense to me because the 750mA trickle charger couldn't keep up with this, and only my 6A big charger would get the battery back up.

* rolled up sleeves and went after the starter cable at Terminal 50 (on the starter motor). The static current draw went immediately down to 13mA (!!!). Trickle charger was now making a difference.

* ordered refurb starter on eBay and installed after car sat for a few days on the trickle charger.

* static discharge on the battery still way down at 13mA, so the problem with the parasitic drain appears to be resolved, though I'll be watching it closely.

If anyone can comment on whether a 13mA static drain is normal, I'd appreciate it!

On another note, while accessing the starter motor I loosened the throttle body and rotated it up per instructions (e.g., 101 Boxster projects). I think something got tweaked, though, because on first startup after putting everything back together, the engine idled roughly and would die if the throttle was opened. Vacuum leak? Checked everything 5 more times -- tube to oil separator, oil fill tube, tiny vac tube connecting to back of throttle body, all seem OK. There wasn't that much to undo and redo.

Next day, car starts up and I can drive it around, but idle is still rough and the engine sometimes dies when pulling to a stop. CEL was on the night before, then off the next day. Trying to get my new Durametric to work with Mac/VMWare/Win 7, but no joy -- "cable not connected" problem. This will be for another thread once I can get more info from the Durametric.

Thanks for the great info on this forum!

[mikefocke]

Years ago disraeli posted this on Porsche Pete's Boxster Board

"The factory technical manual (Section 97-07 page 2) has the following table of total electrical load after the car has been shut off (ModelYear 02):

(electrical current is worst case, i.e. car loaded w/all options...)

FROM TO mA

0 min 5 min up to approx. 950

6 min 15 min up to approx. 900

16 min 20 min up to approx. 750

21 min 60 min up to approx. 50

61 min until the battery is empty up to approx. 30

1000mA equals, of course, one amp.

If the car had no options whatsoever, the load after 60 min would be 17mA instead of 30mA.

[RadioDjKev]

That was 5 years ago I had that drain on my battery. It was the starter. Lucky for me I did not replace anything else, only starter. I miss my Porsche

[oboxster]

Mike - thanks for the numbers! It looks like the battery draw is back in the ballpark at around 17mA.

DJKev - Dude!! I read and reread every word on this thread you started way back when, and it really helped me out. It's great how this stuff lives on and on.

Thanks, guys!

[oboxster]

Hey all,

After putting the new starter in, I guess I must have convinced myself that the electrical drain problem was solved. Not so.

More recently, after hammering the battery every night with a 6A charger for a long time, the battery finally gave up and Sears swapped in a new one on warranty. That battery was drained so low as to not even bump the starter after one night (sans charger).

I had picked up a refurbed Bosch alternator a while back, which was in a box on the garage floor because I never got around to installing it. The car went to the local SD Porsche dealership and they tested away at the system trying to find the source of the 3A drain. Turns out it was the alternator all along!

The car starts like a freaking champ now -- new battery, new alt, fresh starter. Life's good. Wife is happy (it's her car) ...