Weird voltage from new alternator

[Peachbutt]

Hello all.
After the old alternator died we installed a new reconditioned one on our 6R 1.2 TDI with start stop function.
Now ive learned that it only charges when needed, the voltage fluctuates very consistant between 12.5 -14.8 volt on idle it dips to 14,8v every 2 sec 2 times with 0.5 sec interval, i think this is a strange behaviour, can someone help me confirm if this is right or wrong please?
I have controled with VCDS and no fault codes, light in dashboard is off etc.

[RUM4MO]

It might be working as intended, I always have a 12V plug-in DVM in the power socket in my wife's 2015 Polo 1.2TSI 110PS - so the later 6C version of your car, but obviously it also has auto Stop/Start as so a very smart alternator.

I can drive that car in a way that starts with auto Stop being possible, if allowed to operate and end the journey with auto Stop not being enabled - just because the car has maximised the charge being fed into the battery and so is harvesting it.

If I drive it "forcefully" it will always have auto Stop enabled after driving less than a mile - as long as I am not demanding too much heating or cooling for the cabin air.

How that or any smart alternator operates will also depend on the health of your battery, maybe get that health checked.

Edit:- it is often the way, that we don't know how that original alternator was working - before it failed to work, so maybe you have nothing to compare it with, just a gut feeling/logic.

[ciclo]

Due to the mentioned symptoms, you may need to perform Basic Setting for the new voltage regulator... this way, the Gateway will know, via the LIN, which alternator has been installed.
The presence or absence of faults in the diagnostics may depend on the date of the software used.

E.g. https://uk-polos.net/viewtopic.php?p=604140#p604140 (VAS)

I don't know if VCDS will offer you this Basic Setting for your GW/POLO.

[Peachbutt]

Thx for the reply’s.
It wont let me do 04 basic, so i guess it will adapt as i go, hopefully
Anything else i can do maybe?

[Peachbutt]

It might be working as intended, I always have a 12V plug-in DVM in the power socket in my wife's 2015 Polo 1.2TSI 110PS - so the later 6C version of your car, but obviously it also has auto Stop/Start as so a very smart alternator.

I can drive that car in a way that starts with auto Stop being possible, if allowed to operate and end the journey with auto Stop not being enabled - just because the car has maximised the charge being fed into the battery and so is harvesting it.

If I drive it "forcefully" it will always have auto Stop enabled after driving less than a mile - as long as I am not demanding too much heating or cooling for the cabin air.

How that or any smart alternator operates will also depend on the health of your battery, maybe get that health checked.

Edit:- it is often the way, that we don't know how that original alternator was working - before it failed to work, so maybe you have nothing to compare it with, just a gut feeling/logic.

Thats good to know, it does feel wierd but im not used to alternators “adapting” to how you drive so will be getting some experience there

We will drive it for now and see how it operates, it seems not much else to do

[ciclo]

Thx for the reply’s.
It wont let me do 04 basic, so i guess it will adapt as i go, hopefully
Anything else i can do maybe?

Try to find the Basic Setting of the Alternator/Generator voltage regulator at 'Address 19' Gateway, NOT in Battery Monitoring Control Module (Batteriregulering) 'Address 61'.

I guess VCDS won't provide you with a guided function once you enter the Basic Setting, so you should try to follow the sequence indicated in my video with ODIS... but with VCDS.
https://www.youtube.com/embed/IV2fPn4c- ... autoplay=1

I guess you'll see something like this:

It depends on the GW installed on your POLO.

[RUM4MO]

I asked a mechanic who is a part owner of a proper VW Group Indie workshop about the need to "introduce" any new "battery management modules" - the dongle that gets connected to the battery earth, and he said that they were just "plug and play" so I'd think same for alternator - but that is just a guess!

One totally unconnected comment, I have a 2011 Audi S4 6MT and that model of car and some similar powered VW Group cars with manual gearboxes can end up with problems starting the engine as the "engine start enable" sensor is built into the clutch master cylinder. Due to a combination of "bad design integration" of the actual geometry etc of the system, coupled with a crazy " auto adjusting clutch cover" you can find that with the clutch pedal fully down to the floor, engine enable point has not been reached! So, what is effectively happening is, the clutch slave cylinder gets forced to the end of its travel and the clutch master cylinder piston has not gone far enough down its bore to reach the "engine start enable" sensor position! Frequently "mashing" your foot down on the clutch pedal can end up with the end of the plastic clutch slave cylinder getting broken off, so you get "engine start" but now might end up running out of clutch fluid if you are not lucky!
Edit:- sorry missed saying what the DIYer fix is, you buy a new clutch slave cylinder, cut its push rod into 2 parts, and add 5mm spacer and weld the push rod back up, this forces the slave cylinder piston further back its bore by 5mm when the clutch pedal to fully up. Audi fix costs £2000 or £4000, and it involves charging you for replacing the original design clutch cover plate with a later version that works, also replacing the clutch release arm pivot which originally was the wrong height, for one that is a more suitable height - so the owner ends up paying a lot of money for an Audi design error, no change there then!
So, why I'm mentioning this is, I felt the need to find where I could monitor this in my wife's 2015 VW Polo 1.2TSI, and it can be found in ENGINE - IDE00---- Starter control: Interlock- or P/N-signal-Bits I forgot to check the actual full "number" of that, the value changes from 0 at clutch pedal up, to 65 at pedal 25%>85% roughly, and 81 at pedal 85%>100% roughly. Someone might find that useful sometime, as for my 2011 Audi S4, it is "pre UDS" and I know where to find that in that car. One annoying thing was, using VCDS with its latest update and my WIN10 laptop, the listing of these IDE00---- appeared in a very narrow vertical letterbox window - not helpful! On an older and fully up to date other WIN10 laptop and up to date VCDS, the view was a lot better, I must investigate that before it causes me issues!

End of off topic part of posting! Sorry edited my posting later!

[ciclo]

Thanks for the additional information RUM4MO.

For the 6R, and via coding, you also need to tell the J367 (BattMoniContrModu) which alternator is installed.

This is from a 1.2 TDI Bluemotion 'C' MY, that is, with BCM 6R0...088 instead of 7H0...090, however, it is easy to verify the Bytes.

[RUM4MO]

I added some content to my rambling off topic section part of my previous post - to outline what DIYers ended up doing.

Anyway, back on topic, yes that makes a lot of sense if you end up fitting a different alternator than that originally fitted, I had not considered that someone would try doing that.

I was a bit naughty when I replaced the alternator on my older daughter's 2009 SEAT Ibiza 1.4 16V, I did fit the exactly correct model of Bosch alternator, but, it was one with a slightly different - smaller, pulley size, that was good enough for that much earlier car without smart charging to need to keep happy.

[ciclo]

You achieved a fast alternator...
It's not recommended but if that's how it went well, it is well done.

Going back to the topic, it was mentioned that the alternator was reconditioned...

[ciclo]

One annoying thing was, using VCDS with its latest update and my WIN10 laptop, the listing of these IDE00---- appeared in a very narrow vertical letterbox window - not helpful! On an older and fully up to date other WIN10 laptop and up to date VCDS, the view was a lot better, I must investigate that before it causes me issues!

Have you tried expanding the vertical window by placing the pointer on the edge of the window?...

[RUM4MO]

Thanks for that suggestion when using VCDS, I did manage to drag the lower right corner of that vertical "letter box" window to open it up enough to see the descriptions, and I had to do that when using VCDS on my 2011 Audi B8 S4 as its ENGINE controller is UDS compliant, despite what all Audi related internet forums say, so I've found to monitor the clutch pedal switches (which are mounted on the clutch master cylinder), so now I can extend the clutch push rod and check that this does not change both these switches switching points too much - though at its limits, this is only a low temperature problem.

Also, yes, I missed the point that the OP had fitted a reconditioned alternator, so maybe not exactly the same as the original one.

[Peachbutt]

Thx for the reply’s.
It wont let me do 04 basic, so i guess it will adapt as i go, hopefully
Anything else i can do maybe?

Try to find the Basic Setting of the Alternator/Generator voltage regulator at 'Address 19' Gateway, NOT in Battery Monitoring Control Module (Batteriregulering) 'Address 61'.

I guess VCDS won't provide you with a guided function once you enter the Basic Setting, so you should try to follow the sequence indicated in my video with ODIS... but with VCDS.
https://www.youtube.com/embed/IV2fPn4c- ... autoplay=1

I guess you'll see something like this:

It depends on the GW installed on your POLO.

Cheers will try do do this when i come home, my other car just ran into engine issues so im getting desperate now LOL

[Peachbutt]

It wont allow me to do basic setting in can-gateway

I checked the coding for the alternator and it showed a diff gearing then yours.
Ao i changed it for yours instead, dont know if it will change anything

[ciclo]

Generator Gear Ratio is the result of dividing the crankshaft pulley outer diameter by the alternator pulley outer diameter.
After reviewing a few AutoScan 6R 1.2TDI Bluemotion models, the most common hexadecimal values ​​are 5A HEX and 59 HEX.
This is important for proper alternator operation across the entire rpm range.

For a short period, monitor the alternator's performance as you did. If there are no improvements/changes, return to the 59 HEX value.

I assume you don't have information on the part number of the reconditioned alternator...?