987.2 battery drain problem ?

[Pinewood]

26 minutes ago, Medic-one said:

I'm gonna drive over to London this afternoon with a whole list of questions to ask, and to drive a pdk for the first time. 

Thanks again for all the help so far folks. 

push the lever over and try some manual changes as well. push fwd to change up, pull back to change down

[DaveEFI]

43 minutes ago, Medic-one said:

I'm gonna drive over to London this afternoon with a whole list of questions to ask, and to drive a pdk for the first time. 

Thanks again for all the help so far folks. 

Assuming you've driven an auto before, you'll not find it that different. My 2011 is a silky smooth as any when changing gear at normal speeds. They are a bit different from a torque converter transmission when manoeuvring - like say parking up. The way they 'creep' and 'unstick' from stationary slightly different. But you do get used to this.

[Medic-one]

My jag is automatic so I'm used (and bored) of fully auto, I just want the option of being able to select/gears when I want during a spirited drive. 

My wife's smart brabus has paddles on the wheel, but it's a single clutch and takes like a good second to respond so nothing like what I expect pdk will feel like. 

[Paul P]

2 hours ago, Medic-one said:

My jag is automatic so I'm used (and bored) of fully auto, I just want the option of being able to select/gears when I want during a spirited drive. 

My wife's smart brabus has paddles on the wheel, but it's a single clutch and takes like a good second to respond so nothing like what I expect pdk will feel like. 

Purely personal choice but I love the pdk. And you can get as involved as you want it gear changes.  It won’t let you stall.  So if in manual and you stop it will change to first and similarly it won’t take a higher or lower gear if it just can’t do it so saves you from yourself if you fumble a change ( which is where most over revs occur in manuals apparently)

on almost all circumstances it’s great and on the odd occasion where you know best just tell it what you want.  Even in full auto there are various ways (throttle blips, kick down, buttons/paddles, and even braking hard before turning ) which communicate let’s play to the box. 

[iborguk]

2 hours ago, Medic-one said:

My jag is automatic so I'm used (and bored) of fully auto, I just want the option of being able to select/gears when I want during a spirited drive. 

My wife's smart brabus has paddles on the wheel, but it's a single clutch and takes like a good second to respond so nothing like what I expect pdk will feel like. 

I went from a 6 speed manual 987.1 to current PDK. Was unsure I’d enjoy PDK before I tried one. Gear changes are quick. I’ve got paddles and love it. I can be as engaged as I want to be or let the car do the work.

As has been said all personal choice. On the right car I wouldn’t rule it out for being either manual or PDK. They are both great on these cars imho.

Good luck re the car.

[DaveEFI]

2 hours ago, Medic-one said:

My jag is automatic so I'm used (and bored) of fully auto, I just want the option of being able to select/gears when I want during a spirited drive. 

My wife's smart brabus has paddles on the wheel, but it's a single clutch and takes like a good second to respond so nothing like what I expect pdk will feel like. 

Ordinary autos that allow you to select gears ain't uncommon. My late 90s BMW had Steptronic which had the same gear lever selection as the PDK, but no steering wheel control. It's really up to the car maker what they want to fit. My PDK isn't instantaneous when you tell it to shift. Think later versions may be faster. But perhaps a trade off between smooth shifting and jerky.

[Medic-one]

So my battery drain problem still seems to happen every now and then, randomly and I haven't been able to find out the cause yet... 

I've currently got this battery in it, which according to the receipts was fitted in February 2020 : 



Is that a decent brand ? 

Also, how accurate are those battery monitors ? I've got the app on my phone and that connects to bluetooth and tells me what the battery is like, but a while back it kept telling me the battery is charging (like it does when it's connected to my CTEK) even when it wasn't.  
I've removed and reinstalled the app, and it seems to work again now, but still wonder a bit how accurate it is...

I posted this last year in another thread, but just trying to keep everything battery related together in here now...

When buying the car I've gone through all of the online posts and messages of the previous owner again :

- February 2020.  "Dreaded PCM rebooting, doing it a lot". (Porsche facebook group)

There's a receipt from a Porsche specialist (Brooklands Kent Ltd) from 22nd of February 2020 which is a 60K service as well as "Remove PCM unit & replace battery", and under parts there a £ 130, Exide premium battery listed, which is what's still in the car now.

- March 2020. Something draining the battery after it went in for a service, so much so that it won't trickle charge. Struggling to sort it due to everything being shut due to lockdown. (Porsche facebook group).

So I assume that must be that service mentioned above then, and then no further posts in that group, until his for sale post in April this year, which I replied to.

When I asked him about it the issue's mentioned above he said he replaced the heater unit, and in the receipts pack there is a receipt for a 997 heater control unit (£ 390,) from August 2020 and he said he got a new battery as the old one drained too much for his liking, which I assume is the one from that receipt from Brooklands Ltd.

He also said he had the PCM repaired, and that there were coffee stains on the buttons (from a drink in the drinks holder splashing) and he said he hadn't had any more issue's since that was repaired.

Then when I wanted to go and pick it up we had to cancel as the battery was flat again and he booked it into a Porsche ?OPC dealer for early May and was told it would be £ 192, for diagnostics.  They then rang him and said they found a problem but hadn't got to the bottom of it yet, and they were gonna leave it on the computer overnight.

He said it had been fine for the week leading up to that, and that he had been measuring the voltage every day, which was normal.

He chased up the garage and was told that something is draining the battery, but they're not sure what yet.

The next day they contacted him and I got this message :  "So porsche reckon its either the PCM - that I had repaired last year, good guy in North London, I'm 100% sure he'll take a look at it - or the heater which I replaced last year."


I bought a CTEK unit not long after I had the car, and tend to use that when I don't use the car for a while and not had much issue's with it. 

The problem is there's no consistency with this issue.  So far i've done : 

1) Removed PCM fuse, left it in my garage for a few days, not on the CTEK, and battery remained fine (99 - 100% through the bluetooth app). 
I put the PCM fuse back in, drove it, put in back in my garage, not on the CTEK, and again battery remained fine for several days whilst not in use. 

2) On recommendations from here I bought one of those cig lighter voltage meters which shows show just over 12v at idle and around 14.4v driving along so the Alternator seems fine.

And I've been keeping notes of when it happened to try and pinpoint the cause but not much luck there. 

Last summer drove it all through Holland for 2 weeks, done nearly 1200 miles that trip, with loads of small journeys and days of not using the car and had no issue's at all. 
Came home, used it the day after, but then the next day battery was dead and car wouldn't start until recharged by Ctek again.

Done a daily log from last month onwards but still not much more information : 

* 12/03/22 Drove to breakfast club, removed USB stick after parking up, not on ctek.

* 15/03/22 Battery at 0%. Charged for few hours, radio came on when starting the car (always turn it off before shutting engine off), put car inside and back on CTEK.

* 24/03/22 battery 100% , went for a drive, left off CTEK in garage.

* 25/03 - 01/04 - checked daily through bluetooth app, whilst not on CTEK, battery remained at 100% for 8 days. 

* 02/04/22 - Battery 99% , car hasn't been used or started or on CTEK for 9 days now.

* 03/04/22 - Battery 99%

* 04/04/22 - Battery 94% at 10:00 
* 04/04/22 - Battery 94% at 11:30 - Car still not been touched since parking up (without CTEK) for 15 days now.  Took it out for a spin as had to refuel for next day.
* 04/04/22 - Battery 99% at 16:30 - After going out for fuel earlier in the day.  Parked on drive, not on CTEK.
* 04/04/22 - Battery 100% at 21:00. 

* 05/04/22 - Battery 100% at 05:30, drove to work (10 minute journey). Finished at 18:00, still 100% before leaving work.  Battery 98% by 21:30

* 06/04/22 - Battery 96% at 05:30, drove to work, battery showing 'low' 49% after work, but started fine and drove home.  Was 64% when I got home at 18:30 (engine off).
* 06/04/22 - Parked on drive, not on the CTEK, it was showing 99% by 20:00, and 100% by 21:00, baring in mind it was 64% when I parked up, and it wasn't on the CTEK...

Can a Battery charge itself whilst not on a CTEK ?? Or is it more likely this battery monitor that's not accurate...

* 07/04/22 - Didn't have time to check in the morning, but by 18:30 it was sitting at 90%

* 08/04/22 - And now since getting up it started at 81% and is now at 80%. 


So I have 15 days off the CTEK and it stays fine, then after 1 drive I had no change, after the same drive the next day it had gone from 96% to 49% , but after parking up at 64% and not on the CTEK it takes itself up to 100% again...   I'm well confused 😵

 

[Menoporsche]

Wondering if it’s discharging or not charging while driving. Alternator issues?

Random thought…

[Medic-one]

11 minutes ago, Menoporsche said:

Wondering if it’s discharging or not charging while driving. Alternator issues?

Random thought…

But then shouldn't it do that consistently, and show up whilst driving with the voltage in place  ?

[iborguk]

On 4/8/2022 at 1:56 PM, Medic-one said:

But then shouldn't it do that consistently, and show up whilst driving with the voltage in place  ?

I think this is going to be a hard one to diagnose over the Internet.

If it were mine I'd find a decent auto-electrician who specialises in battery drain and be paying them to at least diagnose the parasitic circuit.

Of course your car, your rules and if you want to continue to DIY I'd maybe suggest investing in a decent multi-meter, ruling out circuits by pulling fuses and taking the battery monitor/CTEK out of the testing.

 

 

[Medic-one]

1 minute ago, iborguk said:

I think this is going to be a hard one to diagnose over the Internet.

If it were mine I'd find a decent auto-electrician who specialises in battery drain and be paying them to at least diagnose the parasitic circuit.

Of course your car, your rules and if you want to continue to DIY I'd maybe suggest investing in a decent multi-meter, ruling out circuits by pulling fuses and taking the battery monitor/CTEK out of the testing.

 

 

Yea I think that's gonna have to be the next step (multi-meter, fuse testing etc), just need to buy one and find a free afternoon and go for it.

[Medic-one]

 

I wonder if I accidently found the problem, and it's to do with the alarm/locking system...

Last used to car on Saturday, spirited drive to a breakfast meet with some fellow petrolheads, drove home, radio on, heated seats on, roof down. 

Put the car in the garage around 11:30 ish, not on the CTEK, and haven't used it until today.  

I've checked the battery every morning and evening through the app and for the last 6 (unused) days it has remained at a 100%.

Then today I needed something from the dash cupboard, which means getting in the car which I always do in the same way (as garage is very narrow) which is put keys in and turn (but don't start car) and lower driver side window, with that down I can kinda fold myself into the car (and then normally start it and drive out the garage. 

However today I didn't start it, I just turned the key, put the window down, climbed in & out, window up, closed and locked car, and that was it. 

Before I done that, the battery was sitting 100%, but after retrieving my item and locking the car again it had gone down to 68% in just over 2.5 hours... And I hadn't even driven it or anything 😲 

Can the alarm/security system be faulty and cause a drain like that ? 

I always double check it's locked by trying to open the door with the handle, so car was definitely locked after I retrieved my item, but it just drained the battery by sitting there afterwards. 

Been for a drive now and battery is 100% again, but I do wonder if it's to do with the alarm now... 

[Paul P]

I don't really understand what the monitor is really measuring or interpreting...... so treat this as just someone on the internet rambling on - and happy to be educated if I have it wrong.... but.... for a regular lead acid type battery - that monitor is just reading voltage ?

Based on this - https://batteryworld.varta-automotive.com/en-gb/battery-test-car seems that there is a small voltage difference between "fully charged" ( > 12.4V ) ( 60% and over !)  and "partially charged" 12.0-12.4. (25-60%) - so there is some scale that goes 12V = 25%, 12.4 = 60% - so a .1 V = approx 9 or 10% - so your 68% could mean the battery is about 12.4 to 12.5V and 100% would be  12.6 - 12.7 ish ? 

Assuming that chart, my reading and the battery monitor all agree ...... and I would bet its not an exact science.....

Given the process of unlocking the doors wakes the cars circuits - the ones that sleep after 20 mins, and subsequent other drop off - I would imagine there is a slight drain on the battery - and by the above measures if your battery has gone from say 12.6 to 12.5  - then is that actually a drain or just the "cost of waking the car up, opening the door, firing the interior lights, opening and closing the window and locking. And the monitor itself must place a constant drain on the battery - to run the bluetooth to talk to the app ?

Guess what I am saying is - are you perhaps putting too much "stock" in what that battery monitor is telling you ? - I don't know, not familiar with the method or the monitor and I know you have been chasing a battery drain problem for a while and therefore want to keep on top of it - but perhaps the "headlines" from the monitor are a bit misleading?

Just thinking out loud.....

 

 

[Medic-one]

I think you're right and it just reads voltage, I just bought one because someone else on here said they were good and advised me to get one... 😳

That link is interesting, it does look indeed like it's not really exact science...

I tend to look at the percentage, but maybe I should look at the actual voltage instead :

 
 

 
 

 


This is a link to that monitor think I got :

https://www.amazon.co.uk/Battery-Monitor-Campervans-Compatible-bluetooth/dp/B08VHMJYXY/ref=sr_1_1_sspa?keywords=battery+monitor&qid=1649963356&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExSVJFUk1NSDJPRzRUJmVuY3J5cHRlZElkPUEwNTIxMjkwMVZBRTAyVlE4WTlYViZlbmNyeXB0ZWRBZElkPUEwMjI3NDcwM0JSSVdLQkpXODFPJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== 

Though I don't have my bluetooth on on my phone normally (to save battery), so when I want to check the battery I just activate the Bluetooth, open the app, and then shut both down and deactivate the bluetooth, so it's not like that battery monitor is constantly 'talking' to my phone either. 

Might just connect it and see what the voltage does when I open a door and 'wake' the car up...

 

[BBB]

It’s also worth rechecking the voltage after another hour or so. You’ll find that the voltage will drop immediately after you’ve applied a small load, but then recover somewhat when the load is removed (i.e. when the car goes back to sleep mode).

When removing the load after discharge, the voltage of a healthy battery gradually recovers and rises towards the nominal voltage. Differences in the affinity of metals in the electrodes produce this voltage potential even when the battery is empty

[TV8]

That looks like a volt meter logging device. Battery drain is essentially resistance somewhere in the circuit, resulting in energy being created  and chomping away at the battery. You need to be looking at amps at some point and have a search up on measuring parasitic battery drain using a simple volt/ammeter. Also, try a cigarette lighter volt meter you can see whilst driving and watch what happens to the volts measured on that clean circuit under load and time.

Do you know ohms law? V=IR  if you have 12.5 Volts and a predetermined resistance (R) in the car at different states (wipers, lights stationary alarm etc) you have different currents, which is why you have to be measuring amps (I). It is relatively simple provided it’s not some hidden piece of electronics (eg alarm) and you should be able to quickly check with fuse removal what part of the car could be a problem.  

It’s going to be either to much resistance somewhere, not enough coming out of the alternator or the battery not able to handle it properly (undersized or old/not properly functioning). If you are unlucky, it could be a combination but if it’s a new problem, then hopefully, just one of them!

TVRs are easier to work out but the Boxster is ok. Mine was a combination the alternator and an undersized new battery put on the car just before I bought it. If you are near Bromley, you are welcome to borrow my meters.