TCU Battery at 5%

[Jaggy_Luss]

Hi Folks
The Car is sine 5 days at the dealer for exchange of the rear motor.
During the WE the TCU battery goes at 0%, in the afternoon the charged the HV battery back to 100%, now the TCU battery is back to 5%. Tomorrow morning the car will be back.
TCU seems to work, because WATTCAT works fine.
Any idea about future problems because of the TCU battery?

[dernotte]

When the startup battery and the aux battery are unplugged, the TCU will continue to operate for a little while on its own small AA-type battery (see link). When the startup and aux battery are put in place, the TCU will take its power from those 12v batteries, and refill slowly the TCU battery.

[IynCognito]

Yes, the only way to charge the TCU battery is by driving the car! It will take a few days of driving before the TCU battery goes back up to 90%

[Koala]

Yes, the only way to charge the TCU battery is by driving the car! It will take a few days of driving before the TCU battery goes back up to 90%

Is driving really the only way to charge the TCU battery? Wattcat shows my TCU battery to be at 10%. I will not drive a lot in the next weeks ... will it drain completely then?

[ianipace]

Yes, the only way to charge the TCU battery is by driving the car! It will take a few days of driving before the TCU battery goes back up to 90%

Is driving really the only way to charge the TCU battery? Wattcat shows my TCU battery to be at 10%. I will not drive a lot in the next weeks ... will it drain completely then?

You don't have to 'drive' the car.
Turn the ignition on and press the brake pedal. You can go from P to D and back again.
This tells the car you are 'driving' it!
Much the same occurs if you are in a traffic jam.
Updating the maps can be done this way.
The HV battery has plenty of capacity to keep the 12v batteries and the TCU battery full, yes you will loose a small amount of charge, 1 - 2% not a lot, but it will charge the TCU battery without going anywhere!
Unlike a fossil fuel car with the engine on, ticking over, you won't damage the environment, you can even do it in your garage!!

Stay safe

Ian

[Koala]

Yes, the only way to charge the TCU battery is by driving the car! It will take a few days of driving before the TCU battery goes back up to 90%

Is driving really the only way to charge the TCU battery? Wattcat shows my TCU battery to be at 10%. I will not drive a lot in the next weeks ... will it drain completely then?

You don't have to 'drive' the car.
Turn the ignition on and press the brake pedal. You can go from P to D and back again.
This tells the car you are 'driving' it!
Much the same occurs if you are in a traffic jam.
Updating the maps can be done this way.
The HV battery has plenty of capacity to keep the 12v batteries and the TCU battery full, yes you will loose a small amount of charge, 1 - 2% not a lot, but it will charge the TCU battery without going anywhere!
Unlike a fossil fuel car with the engine on, ticking over, you won't damage the environment, you can even do it in your garage!!

Stay safe

Ian

Thanks for the hint. I have tried this "simulated driving" but the car always shuts down after a while (30 min or so).

I do the map update that way, but w/o pressing the brake pedal (dash shows the blue "off" sign, rather than the green "Ready").
This also works for about 30 min until the car shuts down.