Battery management issues VW New California T7

[Lebuha]

Today we finally got a complete status on the car. It only took 6 weeks. What happened is: The 12V battery and the camping battery have been running low and at one point the high-voltage battery / hybrid battery has started to charge these two batteries. But it has sent 200 (two hundred) amps and has blown two fuse boxes. So these two fuse boxes need to be replaced along with some connectors. They have been ordered but it is not known when they will arrive.
As I understand it, we are dealing with two different faults. One is that the 12V battery and the camping battery are discharging too quickly, the other is that the high-voltage battery is sending out too much energy to charge the 12V battery and the camping battery.
So now we are still waiting for the car to be ready.

 

[burton61]

Today we finally got a complete status on the car. It only took 6 weeks. What happened is: The 12V battery and the camping battery have been running low and at one point the high-voltage battery / hybrid battery has started to charge these two batteries. But it has sent 200 (two hundred) amps and has blown two fuse boxes. So these two fuse boxes need to be replaced along with some connectors. They have been ordered but it is not known when they will arrive.
As I understand it, we are dealing with two different faults. One is that the 12V battery and the camping battery are discharging too quickly, the other is that the high-voltage battery is sending out too much energy to charge the 12V battery and the camping battery.
So now we are still waiting for the car to be ready.

I will need to look back in case I missed something but I was under the impression that the high voltage battery was not connected/ not charging the leisure batteries or starter battery. If it was that would mean you could effectively use your high voltage battery for camping by allowing it to charge your leisure batteries. I understood VW specifically did not allow that configuration and the high voltage battery was only used for stationary/ camping aircon and heating (30 min durations).

Or are they reporting to you that there is a fault that the high voltage battery is charging the other batteries and also with high current? mmm?

 

[sticky1]

Today we finally got a complete status on the car. It only took 6 weeks. What happened is: The 12V battery and the camping battery have been running low and at one point the high-voltage battery / hybrid battery has started to charge these two batteries. But it has sent 200 (two hundred) amps and has blown two fuse boxes. So these two fuse boxes need to be replaced along with some connectors. They have been ordered but it is not known when they will arrive.
As I understand it, we are dealing with two different faults. One is that the 12V battery and the camping battery are discharging too quickly, the other is that the high-voltage battery is sending out too much energy to charge the 12V battery and the camping battery.
So now we are still waiting for the car to be ready.

Interesting set of faults.
I think everyone is seeing the starter battery drain quickly, some more than others.
It looks like you are also saying the leisure battery is also draining - did they know what is drawing the load.
I can only find the wiring that seems to come from the alternator. As far as I can tell everything in the back of the van draws from the leisure batteries. I need to double check the lighting in the rear.
It would make perfect sense to use the EV battery to charge the leisure battery but there will need to be some clever electronics to cope with the different chemistries and capacities.

 

[Californication69]

Today we finally got a complete status on the car. It only took 6 weeks. What happened is: The 12V battery and the camping battery have been running low and at one point the high-voltage battery / hybrid battery has started to charge these two batteries. But it has sent 200 (two hundred) amps and has blown two fuse boxes. So these two fuse boxes need to be replaced along with some connectors. They have been ordered but it is not known when they will arrive.
As I understand it, we are dealing with two different faults. One is that the 12V battery and the camping battery are discharging too quickly, the other is that the high-voltage battery is sending out too much energy to charge the 12V battery and the camping battery.
So now we are still waiting for the car to be ready.

Tak from Copenhagen this Evening !
This is really good information.
Would be nice to have some definitive answers from VW as to how the battery (EV, Starter & Lesuire) interact with each other.
My understanding is that VW don’t have a clue how it works to be honest.
Looks like we could have a clearer picture emerging from the Dansker, which wouldn’t surprise me tbh.
They know their stuff.
Their knowledge with electrical testing equipment ‘tis legendary, way faster than VW can find the blueprints

 

[sticky1]

What I don’t understand is that the hybrid multivan has been around for some time so surely the only addition is the leisure batteries in the back.

 

[Woodstock25]

What I don’t understand is that the hybrid multivan has been around for some time so surely the only addition is the leisure batteries in the back.

Sounds very much like an integration issue around the California fit out on all models.

 

[Lebuha]

Tak from Copenhagen this Evening !
This is really good information.
Would be nice to have some definitive answers from VW as to how the battery (EV, Starter & Lesuire) interact with each other.
My understanding is that VW don’t have a clue how it works to be honest.
Looks like we could have a clearer picture emerging from the Dansker, which wouldn’t surprise me tbh.
They know their stuff.
Their knowledge with electrical testing equipment ‘tis legendary, way faster than VW can find the blueprints

The above is what the dealer said (the director called me yesterday after I had threatened to let the deal go back, and he had clearly gotten into the matter). The dealer said that a specialist from VW in Germany had been up to look at our car and that he had quickly been able to find the fault. It was the first car in Denmark to have that fault, but they had had 5 previous cases in Germany. So yes, the explanation was that the high-voltage battery goes in and charges the 12V battery and the camping battery when they are almost discharged.
I looked at the small screen in the back before the car was picked up. It said that the 12V battery was at 0% and the camping battery at 20%. Incidentally, the small screen was the only thing that worked in the car when it was picked up.

 

[Californication69]

The above is what the dealer said (the director called me yesterday after I had threatened to let the deal go back, and he had clearly gotten into the matter). The dealer said that a specialist from VW in Germany had been up to look at our car and that he had quickly been able to find the fault. It was the first car in Denmark to have that fault, but they had had 5 previous cases in Germany. So yes, the explanation was that the high-voltage battery goes in and charges the 12V battery and the camping battery when they are almost discharged.
I looked at the small screen in the back before the car was picked up. It said that the 12V battery was at 0% and the camping battery at 20%. Incidentally, the small screen was the only thing that worked in the car when it was picked up.

Good to know VW are on to it.
Might take a few weeks but there will be a fix.
Keep us posted !

 

[Lebuha]

Interesting set of faults.
I think everyone is seeing the starter battery drain quickly, some more than others.
It looks like you are also saying the leisure battery is also draining - did they know what is drawing the load.
I can only find the wiring that seems to come from the alternator. As far as I can tell everything in the back of the van draws from the leisure batteries. I need to double check the lighting in the rear.
It would make perfect sense to use the EV battery to charge the leisure battery but there will need to be some clever electronics to cope with the different chemistries and capacities.

No, no information about why the 12V battery and the camping battery discharge so quickly.
It is clearly stated in the manual that these two batteries can be charged at 230V (shore power) connection, but I do not know if and how the 12V battery and the camping battery (and apparently the high-voltage battery) are connected and work together.

 

[vbk1975]

No, no information about why the 12V battery and the camping battery discharge so quickly.
It is clearly stated in the manual that these two batteries can be charged at 230V (shore power) connection, but I do not know if and how the 12V battery and the camping battery (and apparently the high-voltage battery) are connected and work together.

BEVs / PHEVs don't have a traditional 12v alternator. On the PHEV the generator is HV and the energy is used to power the rear electric motor, aircon/heater, DCDC and the HV battery (to varying degrees).

The DCDC converts HV to LV (~12v-14V) power for all the traditional LV parts of the vehicle, (Basically think of the DCDC as an alternator) including the charging of the LV batteries. In addition some vehicles have the ability to top up the 12v Standard Battery via the DCDC using the HV pack even if the vehicle is not in use when it starts to deplete below a certain state of charge. (I don't know these vans do this, but it is fairly normal on newer cars and even allows a smaller 12V battery)

I do wonder if some of the issues being seen is as a result of the extra camper elements being added into the base vehicle and throwing up issues.

I am assuming that the 2nd battery is only used on the camper variant of the PHEV and that between the camper elements and the 2nd battery it has uncovered new conditions.

In terms of the specific issue that @Lebuha has had, the DCDC doesn't push out more energy that required, it can supply probably ~200-260 amps, but the fuses can only have blown if the current is being pulled through them by the devices on the other side. That sort of damage sounds like a dead short. If it was my car, i would want a pile of photos of the damage, specifically the harness, records of exactly what is being replaced and how. 200Amp fuses (this is continuous rating) , so they will need in excess of 400Amps to blow. Fuses of that size are only used on very significant power feeds and it is extremely rare (outside of a crash) to have them blow.

 

[Californication69]

BEVs / PHEVs don't have a traditional 12v alternator. On the PHEV the generator is HV and the energy is used to power the rear electric motor, aircon/heater, DCDC and the HV battery (to varying degrees).

The DCDC converts HV to LV (~12v-14V) power for all the traditional LV parts of the vehicle, (Basically think of the DCDC as an alternator) including the charging of the LV batteries. In addition some vehicles have the ability to top up the 12v Standard Battery via the DCDC using the HV pack even if the vehicle is not in use when it starts to deplete below a certain state of charge. (I don't know these vans do this, but it is fairly normal on newer cars and even allows a smaller 12V battery)

I do wonder if some of the issues being seen is as a result of the extra camper elements being added into the base vehicle and throwing up issues.

I am assuming that the 2nd battery is only used on the camper variant of the PHEV and that between the camper elements and the 2nd battery it has uncovered new conditions.

In terms of the specific issue that @Lebuha has had, the DCDC doesn't push out more energy that required, it can supply probably ~200-260 amps, but the fuses can only have blown if the current is being pulled through them by the devices on the other side. That sort of damage sounds like a dead short. If it was my car, i would want a pile of photos of the damage, specifically the harness, records of exactly what is being replaced and how. 200Amp fuses (this is continuous rating) , so they will need in excess of 400Amps to blow. Fuses of that size are only used on very significant power feeds and it is extremely rare (outside of a crash) to have them blow.

Interesting, thank you for that detailed info.
Wife’s defender has a small 48v / 112ah mild hybrid battery. As well as the cranking 12v battery.
It was the dcdc convertor that so many defenders had that caused issues worldwide for lack of converters.
Very interesting. Could be an issue here with this dcdc convertor.
As you say if the car doesn’t have an alternator, then the 23kWh battery does all the charging of the other two batts.
Hmmmmm

 

[WelshGas]

Interesting, thank you for that detailed info.
Wife’s defender has a small 48v / 112ah mild hybrid battery. As well as the cranking 12v battery.
It was the dcdc convertor that so many defenders had that caused issues worldwide for lack of converters.
Very interesting. Could be an issue here with this dcdc convertor.
As you say if the car doesn’t have an alternator, then the 23kWh battery does all the charging of the other two batts.
Hmmmmm

AI Overview


Volkswagen uses a combined starter/generator, specifically a 48V belt-integrated starter-generator (BSG), in its mild hybrid vehicles. This component replaces the traditional starter motor and alternator, offering several benefits for improved fuel efficiency and performance.


Here's how it works:

• Integrated Function:
  The BSG acts as both a starter motor for the engine and a generator to charge the 48V battery.
  
  
• Belt-Driven:
  It's connected to the engine via a belt, similar to a traditional alternator.
  
  
• Electric Boost:
  During acceleration, it can provide an electric boost to the engine, enhancing performance.
  
  
• Regenerative Braking:
  It also functions as a generator during braking, recovering energy and storing it in the 48V battery.
  
  
• Engine Shut-Off:
  The system allows for "coasting" with the engine off, further improving fuel economy.
  
  
• 48V System:
  The 48V system is separate from the traditional 12V system, with a DC/DC converter linking them.
  

This technology, implemented in models like the Golf, contributes to Volkswagen's strategy of gradually electrifying its vehicle lineup, according to VW.

You can watch this video to learn more about how the 48V mild hybrid system works in VW vehicles:

 

[Jerrywho]

I picked my T7 from the garage yesterday one again; I was told that they charged 1st and also leisure battery but they do no t have a solution yet to avoid discharge. They said again it is a software problem and VW Germany needs to give the solution: I dont know whether my VW garage have any clue either unfortunately.
I will forward them some of the issues mentioned in this thread in case it helps.

 

[Lorri]

We are currently sitting on the details of a T7 hybrid Ocean that we thinking of px for our T6.1.
Reading these comments is cause for concern ? ?
Unless dealership hold true to price quoted of px price to such a time vw have a solution ? ?