NB! something new to coding.

 

 

All true, but.

 

Replaced the original battery to Exide AGM 82 Ah in March.

As my aftermarket`s Webasto Anroid app monitors constantly the voltage, noticed something odd. Sometimes it charged normaly at 14,8 V, sometimes only at 12,8 V.

Ok, summer passed, switched Webasto on one morning and after 10 min received message, battery level low (default Webasto minimum is 11,3 V, but I changed it to 11,8 V before I swapped the batteries.)

 

What the heck? When purchased the battery, the shop coded the car with Exide dongle. Well, connected the VCDS, checked. Battery technology was binary AGM. Which is wrong. Changed to Fleece. All other was good, amperage, producer, all ok.

But nothing changed. I am doing every day 1 hour to work and 1 hour back. Once or twice a month doing 12 hour 1000 km day trip. So charging should not be a problem, normally.

 

Checked the battery with a tester, SOC about 30% and battery at 40%.

 

Went finally to the dealers.

They did a new coding and everything works perfect since:

 

 

2 hours ago, linni said:

Sometimes it charged normaly at 14,8 V, sometimes only at 12,8 V.

 

Normal behaviour for the battery management system that aims to maintain only an 80% SOC (state of charge) to allow regenerative charging when slowing down.

 

2 hours ago, linni said:

Checked the battery with a tester, SOC about 30% and battery at 40%.

 

You will get false readings unless the battery is disconnected from the vehicle even with the ignition turned off, I have a similar tester and found this the hard way, also you will not get correct readings unless you enter the batteries CCA capacity and also under what testing régime.

30% SOC sounds very different to 80% but it is voltage based, unless the battery is disconnected there will be a significant voltage drop from the Canbus nodes communicating with each other, this is visible as the big spark you get when connecting/disconnecting.

The Webasto heater gives a much greater volt drop and I'm not surprised that a battery already at 80% SOC would drop to 11.3v although the alternator should easily overcome this, maybe the battery was above 80% and it was allowing it to discharge.

If ever I am unfortunate enough to end up with a later vehicle the battery mismanagement system and stop/start will be disabled immediately.

About Webasto - I never had a problem at -25 C to work for an hour on the first battery. Like I said,10 minutes at 0 C on replacement battery and voltage went trough the bottom.

 

What I wanted to point out, is that I never met such kind of coding anywhere. The coding provided everywhere in VAG forums just did not work. And this one, never met before, just works.

Maybe it`s due to Exide, not Varta, as original. Shouldn`t be, but some kind of mystery is present.

 

P.S. I know the metrics for the AGM battery work differently, but the behaviour: driving constant speed, charging at 12,3 V. Lifting the throttle, charging goes to 14,7 V. Stepping on throttle, 12,3 V again. This is definitely not normal (installed Torque app on  the phone, which gives instant readings).

 

Edit: Just noticed, that # to allow regenerative charging when slowing down. #. Makes sense. But regen charging only works on braking, not just going engine braking?

 

P.P.S. Start Stop is disabled from the day one.

 

P.P.P.S. At the moment I can see 12,9 V.Which is fully loaded. Never seen this kind of figure before on this battery. Usual was 12,5 after the ride and 12,3 in the mornings. Which is about 50% of capacity.

Meaning the battery management system was living his own life.

 

And finally, why this topic? Was considering to buy a new alternator. OEM alternator costs a cent shy from 1400 euros.

 

 

 

 

 

Edited 19 November, 20241 yr by linni