Far too many folks in this thread think they know more that the manufacturer.

As a reminder, if you fail to operate your vehicle using the settings and specifications provided by the manufacturer you MAY commit a road traffic offence and you MAY invalidate your insurance.

As such then giving advice which encourages other forum members to ignore, change or modify critical functions can create a liability.

TBH @nta16 if you don't really like VAG products then don't buy them, that way VAG will get the message.

3 hours ago, Aldfort said:

As such then giving advice which encourages other forum members to ignore, change or modify critical functions can create a liability.

What critical functions !? I'm sue VW's wunderbar programming wouldn't allow the vehicle to be driven and give triangle of doom and other red warnings if something critical had been ignored, changed, or modified. You really are crutching at non-existent straws.

3 hours ago, Aldfort said:

TBH @nta16 if you don't really like VAG products then don't buy them, that way VAG will get the message.

You seem to miss a lot of what I (repeatedly) put or you'd know I never have, and very probably never would as I'm not a fan of the German marques generally, might consider for a short ownership Mk1 Golf GTi but then it's a tin-top so still limited in its appeal to me.

@nta16

Look hat speed und rpm

5 hours ago, Cairus said:

@nta16

Look hat speed und rpm

Sorry, you have me at a loss, do you me me or someone else?

In your image I see 2068 1/min for revs(?), no speed and 12.934v at something(?) something(?) 30 - I can barely read English let alone another language.

Edited 22 September, 202522 Sep by nta16

10 hours ago, Aldfort said:

Far too many folks in this thread think they know more that the manufacturer.

Difference is many folks in this thread are probably not trying con people, unlike the manufacturer that has been proved to - cough, VW dieselgate (10 years on now).

10 hours ago, Aldfort said:

As a reminder, if you fail to operate your vehicle using the settings and specifications provided by the manufacturer you MAY commit a road traffic offence and you MAY invalidate your insurance.

Uhmmm, how's that square with VW dieselgate(!??!). 😁

nta16 I have you on ignore. First time in ages I've felt the need to block any member on a forum.

22 minutes ago, Aldfort said:

nta16 I have you on ignore. First time in ages I've felt the need to block any member on a forum.

Fair enough. I don't ignore anyone as even those you don't agree with or don't like you can learn from. As you have felt the need to tell me this I will put, as you have also ignored others it may say more about you than me, or it may be the other way round. Your previous decisions on such as leaving threads were as permanent as a Donald J. decision. Until next time.

Good morning, I’d like to update you on the situation. I’ve purchased an ODBeleven device to monitor voltage while driving and to better understand the car’s behaviour. From the initial tests I’ve found that at start-up the voltage stays at 12.8 V, shortly after setting off it settles around 13 V and, during acceleration, it tends to fluctuate between 13 V and 13.5 V. When I lift off the accelerator, for example downhill or when the car is coasting, the value rises to 15 V. In light of these measurements, it seems I can rule out any issues related to the alternator. What do you think?

newer cars have a start stop and an alternator with reversible charging, when you go downhill without throttle, it works as a generator.

also in newer cars, everything is subordinated to economy and ecology.

lead batteries normally like to be charged to the maximum, then they have the longest life and alternators used to work that way.

now not anymore, the alternator puts a minimal load on the engine in order to consume the least amount of fuel, and 80% battery capacity is enough, even if it shortens its lifespan. but that became irrelevant because the battery is a consumable and is expected to be replaced like the spark plugs, 4-5 years. when changing the battery, if it is of the same capacity and output current, it is good to replace only the last digit of the serial number through some diagnostics and the ecu will immediately think that a new battery has been installed. that's what I did with OBD11. but I also entered other things, the manufacturer, etc.

I'm interested, since I now have Exide EFB 60 Ah in 1.5 tsi, when I change it, I'll put AGM because they're even cheaper. then in diagnostics, the serial number, capacity and current are replaced again, and if necessary, the manufacturer.

is it ok to put a new AGM battery in a car that had an EFB? I often see AGM in diesel cars and EFB in petrol cars.

6 minutes ago, imart143 said:

when changing the battery, if it is of the same capacity and output current, it is good to replace only the last digit of the serial number through some diagnostics and the ecu will immediately think that a new battery has been installed. that's what I did with OBD11.

Oh, that’s interesting. I wonder if my OBDeleven 3 can register the new battery on its own. That would be great! It would save me a trip to the auto electrician. Do you happen to know?

go to options garage and find battery managment..

To perform OBDeleven battery adaptation (or registration) on a Gen 3 vehicle, connect the device, navigate to the "Gateway" (Control Unit 19), select "Adaptation," and then fill in the new battery's details like capacity, technology (e.g., AGM), manufacturer, and serial number. The exact location within the Gateway control unit might vary, but the general process involves inputting the new battery's specifications into the adaptation fields to inform the car's system of the replacement.

Steps for OBDeleven Battery Adaptation

Connect OBDeleven: Plug the OBDeleven device into your vehicle's diagnostic (OBD-II) port.

Turn on Ignition: With the ignition on (but the engine not running), open the OBDeleven app.

Find the Gateway: In the app, navigate to the "Gateway" control unit, which is typically Control Unit 19.

Select Adaptation: Choose the "Adaptation" function within the Gateway control unit.

Enter New Battery Details: You'll find fields to enter the new battery's information.

Capacity (Ah): Input the Amp-hour rating of the new battery.

Technology: Specify the battery type, such as AGM or EFB.

Manufacturer: Enter the brand of the battery.

Serial Number: Input the new battery's serial number. If you don't know it, you can often change the last digit, or use a sequence like 1234567890.

Complete Adaptation: Follow the on-screen prompts to finalize the adaptation process.

Why Battery Adaptation is Necessary

Battery registration informs your vehicle's electrical system that a new battery has been installed. This is crucial because the system uses this information to adjust charging cycles and manage the electrical load, ensuring optimal performance and preventing premature failure of the new battery.

It is okay to change from having an EFB to AGM in petrol cars, some scan tools with "battery registration" function offer Fleece as an option, so just use that and not AGM where it is also offered, as that is more specialised versions of AGM batteries, typically the AGM version that people retro fit is just "the AGM equivalent of an EFB" - and that is what battery sellers tend to offer as an alternative to EFB.

This is just the thin edge of the wedge. It's not only VAG cars that are on the coding gravy train. Unless expensive coding software is used when replacing parts troubles will apparently appear later.

I dreaded headlamp bulb replacement on our old car. It took maybe half an hour so long as it wasn't freezing outside, cost around £13 and skinned my knuckles.

I recently read that replacing a VAG headlamp assembly complete with coding with specialist equipment could cost £2000. Buying a cheap replacement and fitting it won't work. Even if all seems well at the outset other modules can start to shut down. The car may end up refusing to start.

6 hours ago, cloudres said:

Oh, that’s interesting. I wonder if my OBDeleven 3 can register the new battery on its own. That would be great! It would save me a trip to the auto electrician. Do you happen to know?

The important things are to change the "serial number" often from VWŠkoda factory this will be ten ones (1111111111) so you can just increase to 1111111112. The type of battery, EFB or AGM (as put VW being VW call AGM "fleece") and make sure you put in the correct Ah.

Below is from when a Briskoda member used his OBDEleven, 4 years ago, to 'code' the battery change on my wife's Fabia Mk3.

Personally I would not leave anything plugged into the OBD port for any longer than necessary.

Always before plugging in a scan tool check the programs on it for your car (model and (part) year) are fully up to date and that it and the car's battery has plenty of charge to cover the period of use.

The voltage reads in your post depend on where and what the OBDEleven is reading at/from on the car. What the readings are will vary depending on a few variables with the car, it's electric use and your electric use, the 12v battery and charging system (and of course the car's computer systems programs).

8 hours ago, cloudres said:

What do you think?

Yes, alternator is working as intended.

20 minutes ago, nta16 said:

Below is from when a Briskoda member used his OBDEleven, 4 years ago, to 'code' the battery change on my wife's Fabia Mk3.

Super useful! Thank you very much.

12 hours ago, rum4mo said:

It is okay to change from having an EFB to AGM in petrol cars, some scan tools with "battery registration" function offer Fleece as an option, so just use that and not AGM where it is also offered, as that is more specialised versions of AGM batteries, typically the AGM version that people retro fit is just "the AGM equivalent of an EFB" - and that is what battery sellers tend to offer as an alternative to EFB.

Fleece?

in OBD11 gen2 i changed battery a year ago and it was impossible to write battery tipe, just in menu choose from EFB or AGM.. so if i put AGM, i should choose AGM, there is no Fleece option.. i have in mind this battery..

Edited 1 October, 20251 Oct by imart143

OBDEleven video in your earlier post shows for later VAG cars Fleece option at 2:39 of video. If you have a 2019 car I would have thought you having an up to date OBDEleven program for your car (model and (part)year) would be best. AGM was an earlier selection for earlier cars and I would guess would work fine but best ask OBDEleven to confirm.

yes i have OBD11 for VAG ver. 0.100.0

car is produced in september 2019, Mlada Boleslav.

it have UDS protocol, now i see manual is on iphone, on android seems look different..

Edited 1 October, 20251 Oct by imart143

This evening I carried out a new test with ODBeleven and noticed that, while driving, the voltage stayed at around 12.5 V. In my opinion, that’s not a normal value. On the few occasions when I was coasting, I recorded readings of about 14.3 V. This leads me to think that something isn’t working properly, most likely linked to the fact that I haven’t yet registered the new battery – which could make sense.

On this point, I tried exploring the various “Applications” of ODBeleven 3 through the iOS app, but I realised that they’re paid and need to be activated individually. For example, the Battery Capacity application costs 30 units (I’m not quite sure whether they’re credits or something else), and the same applies to Battery Type.

What I haven’t managed to figure out, however, is where the battery’s serial number should be entered. That part isn’t clear to me.

Just to clarify, the app I’m using is ODBeleven, which is different from ODBeleven VAG.

Lastly, I ran an error scan and several alerts came up. The next step will therefore be to check whether, and to what extent, they might be related to the battery issue, even though the battery itself has just been replaced.

Edited 1 October, 20251 Oct by cloudres

1 hour ago, cloudres said:

at around 12.5 V. In my opinion, that’s not a normal value

This is normaly by a new batterie. If The SoC&SoH ist by 80% the BMS say Stop To the Generator. If The Car is Sailing, you have the "Fake" recuperation

Edited 1 October, 20251 Oct by Cairus

1 hour ago, cloudres said:

This evening I carried out a new test with ODBeleven and noticed that, while driving, the voltage stayed at around 12.5 V. In my opinion, that’s not a normal value. On the few occasions when I was coasting, I recorded readings of about 14.3 V. This leads me to think that something isn’t working properly, most likely linked to the fact that I haven’t yet registered the new battery – which could make sense.

On this point, I tried exploring the various “Applications” of ODBeleven 3 through the iOS app, but I realised that they’re paid and need to be activated individually. For example, the Battery Capacity application costs 30 units (I’m not quite sure whether they’re credits or something else), and the same applies to Battery Type.

What I haven’t managed to figure out, however, is where the battery’s serial number should be entered. That part isn’t clear to me.

Just to clarify, the app I’m using is ODBeleven, which is different from ODBeleven VAG.

Lastly, I ran an error scan and several alerts came up. The next step will therefore be to check whether, and to what extent, they might be related to the battery issue, even though the battery itself has just been replaced.

My original 6.8 year old battery never charges at less than 13.5V/1.0 to 2.0A, even with a SOC of 83% and 14.7/14.9V on the overrun, its possible that your OBDelevan is reading ~ 0.5V low, in which case the battery charging looks about correct but again I can only suggest getting the battery coded properly to remove all doubt.

Edited 1 October, 20251 Oct by Johngerard

To clear any doubts, I’m opening a ticket on the ODBeleven forum. This is exactly the kind of situation where I’m already wondering if I wouldn’t have been better off going straight to an auto electrician… 😑

Have you tried putting the lights and heated screen on and checked the voltage with the engine running? I know some systems only put charge in when needed

On 01/10/2025 at 22:40, cloudres said:

Just to clarify, the app I’m using is ODBeleven, which is different from ODBeleven VAG.

On 01/10/2025 at 22:40, cloudres said:

I ran an error scan and several alerts came up.

Check with OBDEleven but generally you want the correct and up to date program for your make model and (part) year /VIN other than generic OBD codes.

German marques, including VW for decades have had (over) complex intertwined computer programs so you want an appropriate (up to date) scan toll program to read and interrogate them. You always check and cross reference any information you get from anywhere including test results from a scan tool, don't believe all you see just because it's on some sort of computer. You test the test results to confirm them and always allow for machine and human errors.