[m3wyatt]

The problem isn't so much changing the battery. From what I was told by the service manager the computer needs a complete reload once power is lost. I don't know why this requires several hours.

 

[Nai3t]

I don't know this to be the case with the ID.4 but nevertheless, I had an Audi that I didn't want to mess with the computer resetting, so I connected a battery tender to the jump points while I swapped out batteriy, keeping the computer alive the whole time.

 

[Atlant]

Why does it run low in the first place? Seems like a lemon of a battery to me...

Poor design of the software that enables and disables the DC/DC converter that keeps the battery charged.

 

[Atlant]

There is a constant draw on 12 volt batteries in modern cars and motorcycles. I leave my motorcycle on a battery smart charger to keep it from having a dead battery. Happens to cars too.

There's no reason why a car with 77 kWH of “backup battery” can't keep its 12 V battery fully charged at all times.

 

[JimmyVW]

Poor design of the software that enables and disables the DC/DC converter that keeps the battery charged.

Agree. even worse, in my opinion the car keeps "boiling" the 12v dry by always keeping the charge voltage at 15.x volt, even if the SOC is 100%. I still see this behaviour, initially with 2.3 and now even with 2.4 installed. am hoping that 3.x will improve it.

 

[VW TECHNICIAN]

Agree. even worse, in my opinion the car keeps "boiling" the 12v dry by always keeping the charge voltage at 15.x volt, even if the SOC is 100%. I still see this behaviour, initially with 2.3 and now even with 2.4 installed. am hoping that 3.x will improve it.

What is outside temperature and for how long it keeps going 15.x V .... DC-DC converter is way more smart than what you guys think. And what instrument how you used to measure ( do you trust your multi meter)?

 

[JimmyVW]

What is outside temperature and for how long it keeps going 15.x V .... DC-DC converter is way more smart than what you guys think. And what instrument how you used to measure ( do you trust your multi meter)?

I just read the 12v voltages and SoC status in car scanner and / or OBD11.
last time I checked it, the 12v battery temp was around 32F.

first 50 minute trip over to a somewhat heated parking garage.

trip back home.
each way was 50 minutes, but had to zoom in slightly as car scanner has a bug that fully zoomed out the time-axes shows random values.

 

[JimmyVW]

So based on this chart, the voltage pretty much matches the amount needed given the battery temperature.
but imho should be around the float voltage given the high SoC of the 12v battery.

 

[VW TECHNICIAN]

So based on this chart, the voltage pretty much matches the amount needed given the battery temperature.
but imho should be around the float voltage given the high SoC of the 12v battery.

View attachment 18782

This is to prevent sulfate part of 12v battery maintenance that happens depending on SOC and temperature. And at this stage DC-DC converter only trickle charge battery and all other energy needed is supplied from converter while vehicle is running.
You can manually test under load SOH when you read with scanner 100 SOC.
Can you tell me what is your resting voltage, there is pid for this i have provided?

 

[SunWizard]

So based on this chart, the voltage pretty much matches the amount needed given the battery temperature.
but imho should be around the float voltage given the high SoC of the 12v battery.

The problem with that chart is its AGM and we don't have AGM style battery. For a good deep cycle like AGM or heavy duty Trojans I often used, at 77F the experts say daily charge 14.7v, then quickly drop to float 13.5v, and equalize once a month 16.2v for a short period only. We poor 2021 owners have the weak SLI style battery that can't handle that deep cycle voltage profile, yet our BMS is going even higher volts than those heavy duty deep cycle can handle. This results in damage from the lead plates disintegrating. I used to have a bank of batteries with clear cases and I could watch them disintegrate even on the large heavy duty deep cycle solar batteries (edit: during each equalizing cycle)

 

[VW TECHNICIAN]

The problem with that chart is its AGM and we don't have AGM style battery. For a good deep cycle like AGM or heavy duty Trojans I often used, at 77F the experts say daily charge 14.7v, then quickly drop to float 13.5v, and equalize once a month 16.2v for a short period only. We poor 2021 owners have the weak SLI style battery that can't handle that deep cycle voltage profile, yet our BMS is going even higher volts than those heavy duty deep cycle can handle. This results in damage from the lead plates disintegrating. I used to have a bank of batteries with clear cases and I could watch them disintegrate even on the large heavy duty deep cycle solar batteries (edit: during each equalizing cycle)

I would love to see graphs for onboard DC-DC converter
With this values
12V battery SOC
12V battery voltage while onboard DC-DC converter is active
12V battery temperature
How much power is onboard DC-DC converter delivering
And actuall 12V users energy required while vehicle is running or being driven.
On 3 mules I had so far over the years i have not yet seen 12V battery getting charged to 100% SOC ( i may miss it because i have never logged this intensively). There is algorithm to charge 12V battery to 100% SOC but this happens mostly with long term regen active or if software decides to bring 12V battery for SOH calculations. I'm missing something from your post...valuable information. I will do some logging on my side with 2023 when I get back to US

 

[JimmyVW]

I would love to see graphs for onboard DC-DC converter
With this values
12V battery SOC
12V battery voltage while onboard DC-DC converter is active
12V battery temperature
How much power is onboard DC-DC converter delivering
And actuall 12V users energy required while vehicle is running or being driven.
On 3 mules I had so far over the years i have not yet seen 12V battery getting charged to 100% SOC ( i may miss it because i have never logged this intensively). There is algorithm to charge 12V battery to 100% SOC but this happens mostly with long term regen active or if software decides to bring 12V battery for SOH calculations. I'm missing something from your post...valuable information. I will do some logging on my side with 2023 when I get back to US

Here is another one. Not sure where I can get the DC-DC values from, will see if I can find those and add them to the log next time :

 

[VW TECHNICIAN]

Here is another one. Not sure where I can get the DC-DC values from, will see if I can find those and add them to the log next time :
View attachment 19380

This doesn't look good...you will have to change 12V battery adaptation as soon as possible to EFB+.
Are this graphs stationary?
Current delivery is quite low for vehicles in motion?

 

[JimmyVW]

This doesn't look good...you will have to change 12V battery adaptation as soon as possible to EFB+.
Are this graphs stationary?
Current delivery is quite low for vehicles in motion?

No, Driving. This was a +/- 100 mile drive.

only times I see a high current is when I step into the car and "wake it"
The one above was the trip back home. the one below is the trip to my destination.
the 12v spikes are when I got out of the car and back in to plug in and remove a fast charger. I left the dongle logging during the time.

 

[VW TECHNICIAN]

Here is another one. Not sure where I can get the DC-DC values from, will see if I can find those and add them to the log next time :
View attachment 19380

SOC is going way too fast to 100% SOC.

 

[VW TECHNICIAN]

No, Driving. This was a +/- 100 mile drive.

Let me know when you do adaptation to EFB+ chemistry. Or have them change this with VW service departments.....What is SOH showing for your 12V battery?.
Proof of obdeleven screen adaptation values would be enough ( obdeleven is certified and approved aftermarket solution scanner by VW company)

 

[JimmyVW]

BTW: SOC dropping from 100% to 90% in 5 hours of parking is also massive imho.

 

[SunWizard]

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. My expert sources say at 10F the float voltage should be 14.6v max. after applying temp. compensation to the 77F float of 13.5v.

 

[JimmyVW]

Let me know when you do adaptation to EFB+ chemistry. Or have them change this with VW service departments.....What is SOH showing for your 12V battery?.
Proof of obdeleven screen adaptation values would be enough ( obdeleven is certified and approved aftermarket solution scanner by VW company)

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.

 

[VW TECHNICIAN]

View attachment 19381

BTW: SOC dropping from 100% to 90% in 5 hours of parking is also massive imho.

What draws you see when you live vehicle and for how long they happen..
.i know that you are on old software. If impossible with dongle....you can use current clamp meter to keep eye on this.
Can you post resting 12V battery voltage pid? It is available in carscanner app for ID4....i have sent this pid 50 days ago to carscanner app developer.