Another Stop/Start Fiasco

[DuncanDisorderly]

2 hours ago, varooom said:

Only basic, but did some quick and dirty data logging.

 

RPM over initial 30s cold startup (slightly lower Voltage as I was setting up with engine off of course - was 12.3V on meter)

/cdn-cgi/mirage/999cd83e4192d1c1cc071dfe9bde5387f8f3c499d44689904e0a00c57b952716/1280/https://www.briskoda.net/forums/uploads/monthly_2023_01/RPM.thumb.png.6fcb6b08d331d60c72a756e6f1cc114f.png

 

 

Battery Voltage over the first 30s after cold start (the lower Voltage when cranking was to be expected as it took time to setup datalogging, the droop at 15s was heated screen going on)

I recorded about 3 minutes of data, that was over 14 Volts, as the heated screens were on, and the Voltage didn't drop lower than this.

/cdn-cgi/mirage/999cd83e4192d1c1cc071dfe9bde5387f8f3c499d44689904e0a00c57b952716/1280/https://www.briskoda.net/forums/uploads/monthly_2023_01/491148205_BatteryVoltage.thumb.png.9d66de7941aba4579e2d14684a0a7e19.png

Thanks Varooom, that link is a great help, explains exactly what components contribute to the system. 

I've got a laptop working, and downloaded VCDS. Just thought it was a long shot, but I had a 2002 A6 All Road years ago and remember buying a RossTech adapter for it. Didn't hold much hope, but dug it out the garage and it works! It's a HEX-USB+Can.  Also found an old K-line adapter, can't even remember what I got that for. 

 

I've connected the car up and tested the ports, it's all good to go. I'll have a set-to with it tomorrow and see what's going on. 

 

Thanks for your support so far! 

[varooom]

That was a great "barn" find then 😂

Best of luck with it tomorrow then.

[DuncanDisorderly]

Well this is a bit embarrassing, what a difference it makes having the right tools for the job. Battery coding was previously done with a  handheld unit (not mine).

Checked the 4 battery coding adaptions this morning:

Manufacturer, VOL

Type, Fleece

Serial number, random

AH, was set at 7ah instead of 70ah. 

 

No wonder it thinks the battery is almost flat 😂

 

AmpHours now corrected, battery serial number +1 and graphed. Quick run around town and the stop/start is working perfectly!  Moreso the charge rate looks more like it should (12.3v steady with ignition, dipped to 10.5v cranking, elevated to 14.3 running) now it knows its charging a 70ah battery, not a 7ah unit 🙄

Thanks for your help guys

Edited 20 January, 2023 by DuncanDisorderly

[Vahids]

25 minutes ago, DuncanDisorderly said:

Well this is a bit embarrassing, what a difference it makes having the right tools for the job. Battery coding was previously done with a  handheld unit (not mine).

Checked the 4 battery coding adaptions this morning:

Manufacturer, VOL

Type, Fleece

Serial number, random

AH, was set at 7ah instead of 70ah. 

 

No wonder it thinks the battery is almost flat 😂

 

AmpHours now corrected, battery serial number +1 and graphed. Quick run around town and the stop/start is working perfectly!  Moreso the charge rate looks more like it should (12.3v steady with ignition, dipped to 10.5v cranking, elevated to 14.3 running) now it knows its charging a 70ah battery, not a 7ah unit 🙄

Thanks for your help guys

All those trouble for the sake of an idiot who set that as 7ah, I hate those people that they don't do a proper job.

[varooom]

I cannot write the swear words in here, but try "un-duck-ing believable!"

 

Last night I was going to link you to a thread I made about battery coding, but clearly you dusted off your VCDS cobwebs fast.

[DuncanDisorderly]

I'm really annoyed with myself for taking other people's word that it was coded. 

Incidentally, the VAG specialist who condemned the first battery told me that these batteries didn't need to be coded in (after they condemned the new battery and fitted a replacement, I specifically asked them to make sure it was coded in).

 

The auto-electrics specialist did find and fix a wiring fault, and re-coded the battery with a handheld tool rather than a scan tool. 

 

Just annoyed with myself that when I had use of VCDS the first time (to check the stop/start minimum voltage hadn't been fiddled) I didn't check the battery coding at the same time. 

 

Now, the original battery that was on the car when I got it that had been left flat for months, I assumed would be shot so replaced it. I charged it with a smart charger a few months ago. Checked it this morning and its still got 12. 1v in it, that *might* actually be still use able! 

[varooom]

You might be lucky with that original battery then, I think they can loose 0.1V per month due to internal resistance?

That's really shocking how they dropped the ball so hard, I guess anyone can label themselves a VAG specialist 🤐

[Warrior193]

36 minutes ago, DuncanDisorderly said:

I'm really annoyed with myself for taking other people's word that it was coded. 

Incidentally, the VAG specialist who condemned the first battery told me that these batteries didn't need to be coded in (after they condemned the new battery and fitted a replacement, I specifically asked them to make sure it was coded in).

 

The auto-electrics specialist did find and fix a wiring fault, and re-coded the battery with a handheld tool rather than a scan tool. 

 

Just annoyed with myself that when I had use of VCDS the first time (to check the stop/start minimum voltage hadn't been fiddled) I didn't check the battery coding at the same time. 

 

Now, the original battery that was on the car when I got it that had been left flat for months, I assumed would be shot so replaced it. I charged it with a smart charger a few months ago. Checked it this morning and its still got 12. 1v in it, that *might* actually be still use able! 

Give the old battery an occasional charge with the smart charger.

All lead acid battery will self-discharge, and the rate varies according to ambient storage temperature - S-D rate is smaller at lower temperatures, but can be as high as 1% of SOC per day at 30deg.C - even on a new battery!

Edited 20 January, 2023 by Warrior193
added note.

[ords]

6 hours ago, DuncanDisorderly said:

I'm really annoyed with myself for taking other people's word that it was coded. 

Incidentally, the VAG specialist who condemned the first battery told me that these batteries didn't need to be coded in (after they condemned the new battery and fitted a replacement, I specifically asked them to make sure it was coded in).

 

The auto-electrics specialist did find and fix a wiring fault, and re-coded the battery with a handheld tool rather than a scan tool. 

 

Just annoyed with myself that when I had use of VCDS the first time (to check the stop/start minimum voltage hadn't been fiddled) I didn't check the battery coding at the same time. 

 

Now, the original battery that was on the car when I got it that had been left flat for months, I assumed would be shot so replaced it. I charged it with a smart charger a few months ago. Checked it this morning and its still got 12. 1v in it, that *might* actually be still use able! 

At least you know which "specialists" to avoid in the future.

[nta16]

Please note - I am not a mechanic or expert in anything.

 

Great news in the end and well done to you for finding it. 👍

 

12.1v is about 50% charge to Ring Automotive or 40% to VW.  From my experience - I'm not an electrician, auto-electrician or VW specialist or specialist of any sort - just my decades of experience dealing with my neighbours 12v car batteries - a long low slow charge of the battery with an appropriate battery charger will get the most into it and out of it, 4 amp fine, 2 amp perhaps even finer.  It will take longer but it will be better, might take 20+ hours to fully recharge so will need some things many don't carry much stock of, patience and time.  I've revived a few "dead" batteries, had 2 failures so far, of course the others weren't dead, in the same way that a "good" battery often isn't when someone tells you it is, in my experience.

 

Then obviously you want to keep an eye on the charged battery to see how well it holds that charge with self-discharge and with load, throwing it on the car for a while would give it a real world test and you've got all the equipment to monitor it now.

 

Cheers.  

Edited 21 January, 2023 by nta16
spelling

[Nogrille]

I think it might be time to name and shame the VAG "specialist"