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cvega
Monza


Joined: 25 Feb 2013
Posts: 154



PostPosted: Sat Jun 02, 2018 10:36 pm    Post subject: battery drain.. but no drain? doing my head in Reply with quote

So lately I've replaced my alternator voltage regulator. Battery seems to drop really low after 3-4 days. Replaced the battery with Bosch S5 74Ah 700cca.
While driving, the car is showing above 14V. So I assume charging is OK.

I've gotten around to measuring the current drawn and I need some guidance.

This is the way i've connected it;
red (10A on the meter) towards negative on chassis
COM to battery negative

After I lock the car, it's displaying 30-ish for a minute, then drops to 11.5-12 (I'm assuming miliamps - i'm using the meter in 200mA mode):


After additional 10 minutes, it drops to 3.3-3.7:


Even 3 hours later, seems to be the same:


So..what is killing the battery???
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2003 996 C2
2017 Leaf 30kWh
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Pickse
Spa-Francorchamps


Joined: 20 Jul 2013
Posts: 320
Location: Fleet, Hants


PostPosted: Sun Jun 03, 2018 7:59 am    Post subject: Reply with quote

I had very similar symptoms on my 996T.
Battery wouldn't last a week although charging was close to 14V.
But sometimes after start it would refuse to produce 14V then after a few seconds would ramp up to the expected charging voltage.

Turned out the serpentine belt was routed incorrectly.
Not enough contact area with the alternator pulley so slipping I guess Question
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andy1985
Trainee


Joined: 28 Apr 2013
Posts: 80
Location: Barnsley


PostPosted: Sun Jun 03, 2018 8:00 am    Post subject: Reply with quote

Your pics aren't working for me and I don't know if i'm reading wrong but it sounds like you are trying to measure current the same way as voltage.

To measure current you need to break the electrical circuit and put the meter inline, eg remove the negative battery terminal, connect one lead to that and then connect the other lead to the battery terminl to complete the circuit again.

DON'T try to start the car like this though.

open the door, ignition on,
trick the latch into thinking the door is closed, igntion off and lock the car up and disable the alarm sensors.
Wait for the car to go to sleep and then check the current draw.
If it is high then begin pulling and replacing fuses 1 by 1 to see which circuit is causing the issue.
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deMort
Zolder


Joined: 21 Mar 2015
Posts: 5146
Location: Brighton


PostPosted: Sun Jun 03, 2018 3:10 pm    Post subject: Reply with quote

Agree

Thats how to do it but the problem is if you just pull off the neg lead the alarm will trip ..

you need to rig up a wire to the battery terminal and the lead so that you can remove it but its still connected .

You can then connect the amp meter leads and remove this wire.

All current will flow through the meter at this point and it will display what it is.

I have a 20 amp meter so i just connect it up with ign on and lock the car .. on a 10 amp meter thats a bit close to the max limit so you might blow the meters fuse if you do it my way .

Set the meter to the 10 amp setting , wait 1 hour to get a true reading .. you want a display of 0.03 ... 30 milliamps .
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cvega
Monza


Joined: 25 Feb 2013
Posts: 154



PostPosted: Sun Jun 03, 2018 3:14 pm    Post subject: Reply with quote

Sorry maybe I didn't describe correctly. The meter is inline on the negative side of battery. I put the key into ignition, disconnect it, reconnect with meter online and lock the car.
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deMort
Zolder


Joined: 21 Mar 2015
Posts: 5146
Location: Brighton


PostPosted: Sun Jun 03, 2018 3:17 pm    Post subject: Reply with quote

In which case you dont have a discharge .

I would watch the meter for a few mins to make sure its not a pulsed discharge .. trackers do this .

Next step .. car running on idle , all electrical loads on then measure the voltage at the battery .. you need about 13.2 .. if below 13 then the alternator or a lead is faulty .
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cubasteve
Österreich


Joined: 03 Mar 2010
Posts: 899
Location: West Hampstead , London , NW2


PostPosted: Sun Jun 03, 2018 3:40 pm    Post subject: Battery problems Reply with quote

Bandit Try a Porsche trickle charger , plugs into the cigarette lighter also the tracker drains battery and after 3 to 4 days the car goes into sleep mode so check it's not just that , Good Luck . Cuba Bandit Bandit Bandit
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Porsche 997, C2S Manual 2007 Coupe , first car was VW Karmann Ghia Coupe .
 



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911munKy
Nürburgring


Joined: 26 Nov 2014
Posts: 455



PostPosted: Sun Jun 03, 2018 11:43 pm    Post subject: Reply with quote

^
That looks like a rebadged CTEC charger.
I bet it’s a lot cheaper without the Porsche logo.

They are very good trickle chargers though.
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cubasteve
Österreich


Joined: 03 Mar 2010
Posts: 899
Location: West Hampstead , London , NW2


PostPosted: Mon Jun 04, 2018 6:40 am    Post subject: Battery problems Reply with quote

Bandit Yes it is a rebadged CTEC charger , make sure you buy the one with cigarette lighter plug in . Cuba Bandit Bandit Bandit
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cvega
Monza


Joined: 25 Feb 2013
Posts: 154



PostPosted: Mon Jun 04, 2018 8:40 am    Post subject: Reply with quote

Thanks chaps, I know all about CTEK chargers but the car should be able to maintain a battery charge for a week without help. For a 3-4 weeks, sure, I'll plug it in, but not every week.

As for the test, I've done a run in the evening, the car was driven the same morning, about 20 miles.
The meter initially shows 12.3V, cranking about 10.8/11 , then sits at about 13.5 for a while (loud whirring sound from the engine bay), goes up to over 14. With load drops to about 13.8 or so (Radio, fans, lights on)
I've recorded this on my phone. Sorry about the sound quality. https://youtu.be/ose8UpdnP94
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Stoo.c
Monza


Joined: 07 Apr 2014
Posts: 176
Location: Hertfordshire


PostPosted: Mon Jun 04, 2018 8:52 am    Post subject: Reply with quote

Did you say that with the engine running, you're getting above 14V showing? That seems a little high to be honest.

Up to 14V of course but above it, I've never experienced on any of my porsches, or any other car for that matter.
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rdodger
Silverstone


Joined: 08 Apr 2018
Posts: 149
Location: Cheshire


PostPosted: Mon Jun 04, 2018 9:00 am    Post subject: Reply with quote

Apart from your choice of music, that all looks normal to me.

As mentioned earlier, is there a tracker that pulses?
 
  
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cvega
Monza


Joined: 25 Feb 2013
Posts: 154



PostPosted: Mon Jun 04, 2018 9:56 am    Post subject: Reply with quote

Sorry about the music, blame Radio1 Very Happy I'm more of radio 4 person, old..

I don't know where to look for the tracker. Can i verify that on the options list perhaps? When i was watching the meter (albeit not too closely), I didn't see draw go up and down. It was sitting at 34-37mA steadily.

A bit lost here...

The battery definitely loses charge, goes down to 11.5-ish after 4 days. It still cranks but it's on the verge of dying then. It's possible that i've not noticed it before fixing the alternator and on the old battery. Now that it _should_ all be fine and it isn't i started paying more attention.

I've used a generic skoda voltage regulator rather than replacing the whole alternator. Is there anything that can be connected / done wrong during changing the regulator? It seems to charge OK whilst its running...
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andy1985
Trainee


Joined: 28 Apr 2013
Posts: 80
Location: Barnsley


PostPosted: Mon Jun 04, 2018 1:03 pm    Post subject: Reply with quote

Has the battery been checked/tested? If you can't find a current drain then it's either something waking up when it shouldn't be or the battery has a dead/dying cell. I'd opt for the latter.

My range rover had pretty much the same symptoms, run it daily and it was fine, leave it for 2 to 3 and it needed a jump.
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cvega
Monza


Joined: 25 Feb 2013
Posts: 154



PostPosted: Mon Jun 04, 2018 1:13 pm    Post subject: Reply with quote

I'd hope a brand new battery isn't shagged... I'll get it tested for a peace of mind.
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deMort
Zolder


Joined: 21 Mar 2015
Posts: 5146
Location: Brighton


PostPosted: Mon Jun 04, 2018 6:54 pm    Post subject: Reply with quote

Theres nothing wrong with the chargeing , the alternator should adapt for the higher electrical loads and thats what its doing .

14 volts is fine , 997 and 15 volts is fine .. its down to the charge state of the battery .

So far you seem to have nothing wrong .. dont have a miniture battery fitted do you ? Very Happy

Ok .. what to suggest .. hmm ..

Foam base panel behind the rear seats , pull that out and youll have an ally panel held in place with 10 mm nuts .. either remove or peer under it .. your looking for a battery .. a long grey lead .. a purple wire , a black wire and another ally box .. that would be a tracker and the battery would be the problem.

Tracker batterys die and the unit trys to charge the battery with engine off which it shouldn,t .. you will get a pulsed discharge of about 1 amp every 30 - 60 seconds .

You havent seen this on your meter but im running out of idears here !

No umbrella against the seat switches .. if full electric seats then just make sure its all moveing on both sides .

i think another discharge check is in order to make sure nothing has been missed .. set it to 10 amps this time .

A meter with a record function is what i use when i get desperate .. i can leave it over night and read max/min so it will 100% prove there is no discharge .

All im left with is the battery is not holding charge for very long .. 4r days is too short a period for a battery to be low enough that it struggles to start .

Mind you .. it might not be the battery .. high resistant starter drawing a lot of current .. in theory a slightly down battery might struggle to turn it fast enough .. when all else fails .. what ever is left etc etc .. logical anyways .
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cubasteve
Österreich


Joined: 03 Mar 2010
Posts: 899
Location: West Hampstead , London , NW2


PostPosted: Mon Jun 04, 2018 9:25 pm    Post subject: Battery problems Reply with quote

hi cvega . I've used these people ; Cartronics , car electronic specialist 01932800800 at 22 High Road , Byfleet , Surrey KT14 7QG .
Cuba Bandit Bandit Bandit
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cvega
Monza


Joined: 25 Feb 2013
Posts: 154



PostPosted: Mon Jun 11, 2018 10:35 am    Post subject: Reply with quote

deMort, thanks for your help so far... update;

I've had a look and pulled off the carpet covering the space behind rear seats. I found the steel plates covering some electrical gubbins there but I can't say I've seen a battery sitting there. I didn't take the covers off as my time was limited, but I took some pictures, maybe they'll shed some light... battery still drains.. drove the car on Friday, 12.8V when switching it off, 11.5V by Sunday... still started and drove ok..

The one thing that HAS changed is that i got the voltage regulator replaced on the alternator (as previously the votage would drop slowly when driving the car from just under 14 to barely above 12 in a space of a 10-20 miles .. could that be done wrong and mess something up ??

pics of the rear seat area: (sorry for bad pictures)
LEFT SIDE
RIGHT SIDE
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eabeukes
Trainee


Joined: 30 Jan 2018
Posts: 97


1999 Porsche 996 Carrera 2

PostPosted: Mon Jun 11, 2018 1:25 pm    Post subject: Reply with quote

cvega wrote:


I don't know where to look for the tracker. Can i verify that on the options list perhaps? When i was watching the meter (albeit not too closely), I didn't see draw go up and down. It was sitting at 34-37mA steadily.
.


Pull out the dashboard speakers (two hex M20? screws) - I found an ancient tracker in there this weekend which was still plumbed in drinking tiny amounts of current! Going to have to perform some surgery to find the base unit, as thats hidden somewhere I still cant find.
 
  
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cubasteve
Österreich


Joined: 03 Mar 2010
Posts: 899
Location: West Hampstead , London , NW2


PostPosted: Mon Jun 11, 2018 1:43 pm    Post subject: Battery problems Reply with quote

Bandit when I had tracker problems Porsche Chiswick had the front bumper off to access part of it . That Tracker turned out to be a big headache , had a new one fitted for £1,200 and that turned out to be a dud batch , so Porsche spent another 5 hours and eventually fitted a 2nd one for free . But Cartronics fit new tractors for about £400 just another Porsche pay treble charge . Cuba Bandit Bandit Bandit
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