[VW TECHNICIAN]

Just for me to be 100% clear.

I open the hood, then sit behind the wheel, so that the high voltage systems latch, then I step on the brake to fully wake the car, and then I try to write the adaptation? or is sitting behind the wheel enough?
just want to triple check the proper procedure.

Yes hitting foot pedal or you can use button on steering wheel

 

[VW TECHNICIAN]

One item I missed on my above post, for AGM never do equalizing voltage since it can permanently damage them. Here is some data I posted in my Experiment watching my 12v battery voltage, and its getting too low every night I have lots of other data recorded and can post more later. SOC is always near 100%, and goes there quickly since its become a very weak battery in only 9 months. Mine often goes to 15.5v like on this graph, and stays there all day when its cold and battery is around 10F and this is much too high for a float voltage.

Can you post resting 12V battery voltage pid
It is available in car scanner app?

 

[JimmyVW]

One item I missed on my above post, for AGM never do equalizing voltage since it can permanently damage them. Here is some data I posted in my Experiment watching my 12v battery voltage, and its getting too low every night I have lots of other data recorded and can post more later. SOC is always near 100%, and goes there quickly since its become a very weak battery in only 9 months. Mine often goes to 15.5v like on this graph, and stays there all day when its cold and battery is around 10F and this is much too high for a float voltage.

isn't the DC-DC current the power that drives the whole 12V circuit of the car, while the 12 Battery Current the power that purely flows from or to the battery?

 

[VW TECHNICIAN]

Resting 12V battery voltage pid will set value when 12V battery maintenance is required.

 

[JimmyVW]

Can you post resting 12V battery voltage pid
It is available in car scanner app?

resting voltage would be when the car is off, wouldn't it? So the 12.44 volt I saw while being out of the car, in the second picture I posted? can't really find dedicated PIDs in carscanner

 

[VW TECHNICIAN]

isn't the DC-DC current the power that drives the whole car, while the 12 Battery Current the power that purely flows from or to the battery?

Which pids are we talking about?
Give me names?

 

[VW TECHNICIAN]

Onboard DC-DC converter module receives information on 12V battery information and 12V demand for energy required...and from this information it will calculate best scenario to maintain energy requirements and boost output if 12V battery needs charging or trickle charge for 12V battery.

 

[VW TECHNICIAN]

resting voltage would be when the car is off, wouldn't it? So the 12.44 volt I saw while being out of the car, in the second picture I posted? can't really find dedicated PIDs in carscanner

Keep looking it is there..... this value is important so i can see what is really happening with your 12V battery and JimmyVW battery?
Or you can use obdeleven if you have one.

 

[JimmyVW]

Keep looking it is there..... this value is important so i can see what is really happening with your 12V battery and JimmyVW battery?
Or you can use obdeleven if you have one.

in what module does that PID sit? happy to walk outside and shove my OBDeleven dongle in there.
(currently I'm grabbing all data from 19.Gateway, not from 8C.BMS or 8105.DC/DC Converter)

 

[SunWizard]

isn't the DC-DC current the power that drives the whole 12V circuit of the car, while the 12 Battery Current the power that purely flows from or to the battery?

Yes this is why I graphed both of those PID, subtract those 2 and the difference is 5A = 75w which is what the parts of the car that stay active like BMS + dongle draws while running car scanner.

 

[VW TECHNICIAN]

in what module does that PID sit? happy to walk outside and shove my OBDeleven dongle in there.
(currently I'm grabbing all data from 19.Gateway, not from 8C.BMS or 8105.DC/DC Converter)

It should be for same module where you have access to adaptation for 12V battery.

 

[SunWizard]

Can you post resting 12V battery voltage pid
It is available in car scanner app?

I will look for it later, my wife is out all day with the car. During my test that I linked, the resting voltage measured with a good quality to 0.01v meter with hood closed, dongle off was 11.7v. The trouble with having the dongle on is that with my weak battery the small 5A load of the dongle and BMS drops the 12v by 0.1 to 0.2v. Does this new resting PID somehow keep track of what the voltage was before the dongle was turned on?

 

[JimmyVW]

Yes this is why I graphed both of those PID, subtract those 2 and the difference is 5A = 75w which is what the parts of the car that stay active like BMS + dongle draws while running car scanner.

I graphed both just a minute ago from my car
Temperature 9C, SOC 87%.
Somehow it missed a few measurements on the DC values.

I started measuring with the car off, then sat in the seat (sharp rise), then at the end pressed the brake to wake it fully. Interestingly enough that dropped the amps on the DC-converter from 80 to 50. No idea why

 

[JimmyVW]

It should be for same module where you have access to adaptation for 12V battery.

doesn’t seem to be in carscanner yet.
this is the only interesting bit I could find from OBDeleven:

 

[VW TECHNICIAN]

doesn’t seem to be in carscanner yet.
this is the only interesting bit I could find from OBDeleven:

View attachment 19387

Battery looks good at resting....you will still have to change adaptation for new 12V battery....current looks suspicious....... 1.473 kw power output ( this is 2X times average).... unless we have all pumps and radiator fan with fan in cabin running at same time.
11.45 V is good for EFB+ chemistry at resting

 

[VW TECHNICIAN]

I will look for it later, my wife is out all day with the car. During my test that I linked, the resting voltage measured with a good quality to 0.01v meter with hood closed, dongle off was 11.7v. The trouble with having the dongle on is that with my weak battery the small 5A load of the dongle and BMS drops the 12v by 0.1 to 0.2v. Does this new resting PID somehow keep track of what the voltage was before the dongle was turned on?

Pid for resting voltage is taken when vehicle is in hibernation ( sleeping).... anything above 10.9 V is ok..... it should be around 11.3-11.7 if vehicle was not running cellular network modem or other maintenance tasks when onboard DC-DC converter was not running.
Pid value is taken when vehicle is in sleep mode. This value is also used for calculation of 12V battery maintenance when necessary.

 

[SunWizard]

Pid for resting voltage is taken when vehicle is in hibernation ( sleeping).... anything above 10.9 V is ok..... it should be around 11.3-11.7 if vehicle was not running cellular network modem or other maintenance tasks when onboard DC-DC converter was not running.
Pid value is taken when vehicle is in sleep mode. This value is also used for calculation of 12V battery maintenance when necessary.

I went through every PID on the latest android app and there is nothing for 12v resting voltage. Hope they will add it someday since it would be useful to troubleshoot a bad 12v battery.

 

[SunWizard]

Here is another typical recent day when the car was holding the 12v too high at 15.45v every time I checked for hours, even though it was always 94-96% SOC. Battery temp was 25F. Edit: note this was also near the time when I am getting a "12v battery low, continue driving" error message, immediately after driving for 45 minutes which should have been charging the entire time (did not have the dongle on, it was my wife driving.)

 

[VW TECHNICIAN]

Here is another typical recent day when the car was holding the 12v too high at 15.45v every time I checked for hours, even though it was always 94-96% SOC. Battery temp was 25F. Edit: note this was also near the time when I am getting a "12v battery low, continue driving" error message, immediately after driving for 45 minutes which should have been charging the entire time (did not have the dongle on, it was my wife driving.)
View attachment 19403

I think you should log enough data and bring this to the service department attention....and have them run ODIS tool for logging rhis parameters regarding 12V battery charging....and after they finish tell them to call engineering department and provide logging on this pids....you may have to live vehicle for a day or two..... this is interesting discovery and it will need some corrections from my side of engineering department.
I'm quite positive that you know EFB+ chemistry and best way how onboard DC-DC converter should be maintaining.... I will do what is needed from my side to make aware of this issue VW engineering.
Thank you for taking your time and pointing me to this bug on our side.....
Quick question are you on EFB+ chemistry? And are you on latest software version?

 

[SunWizard]

Quick question are you on EFB+ chemistry? And are you on latest software version?

No, still on the old 2.1 with 10 month old style battery. I was hoping it would survive until I get into the update Q, but it looks like its going to fail before then. Will showing this data on the charging bug and failing battery get me into the shop Q for the EFB+ and the 3.x update?

Good chargers drop to a float voltage of 13.5 volts in normal usage since holding above that is overcharging. My BMS does not! (at least with my old 2.1 car) I will be very dissapointed if I get updated to 3.x someday soon and I find that its still charging to 15.5v every day!

I have lots of experience with lead acid batteries since my first 2 EVs and my off grid solar house all used 12 to 16 of them for each. And I sold and maintained solar and batteries for around 20 of my off grid neighbors. They were the weak link in solar, so hurray for Li-ion to drop in price by 10 fold.