TCU Battery at 5%

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Jaggy_Luss
Posts: 130
Joined: Mon May 27, 2019 11:54 am
Location: Luxemburg

TCU Battery at 5%

Post by Jaggy_Luss » Tue Jan 12, 2021 7:06 pm

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?

20210112_195523.jpg

Caesium Blue, S, MY2019,
S20C...
SCU,BMS never displayed, H228, H264 done,
Activ air suspension, HUD, drive assist 1&2
18 " with 4 season tyres

dernotte
Posts: 181
Joined: Tue Dec 24, 2019 2:34 pm
Location: Montreal, QC, Canada

Re: TCU Battery at 5%

Post by dernotte » Tue Jan 12, 2021 7:50 pm

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
Posts: 49
Joined: Sun Sep 13, 2020 8:27 pm
Location: Stockport, United Kingdom

Re: TCU Battery at 5%

Post by IynCognito » Tue Jan 12, 2021 8:27 pm

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%

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Koala
Posts: 200
Joined: Sun Mar 17, 2019 8:40 pm
Location: Germany - Bavaria

Re: TCU Battery at 5%

Post by Koala » Mon Jan 18, 2021 6:38 pm

IynCognito wrote:
Tue Jan 12, 2021 8:27 pm
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?
EV400 S, MY2019, Firenze Red, Light Oyster Interieur, Acitve Air suspension, 18" Diamond turned Wheels.
IMC: S20C | TCU: 17.2 | 50.000 KM of happy I-Pace driving since March 14th, 2019

ianipace
Posts: 251
Joined: Sat Nov 09, 2019 9:11 pm
Location: Cardiff, UK

Re: TCU Battery at 5%

Post by ianipace » Mon Jan 18, 2021 7:18 pm

Koala wrote:
Mon Jan 18, 2021 6:38 pm
IynCognito wrote:
Tue Jan 12, 2021 8:27 pm
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
MY2019 SE in Caesium Blue. Panoramic roof and 20" wheels. Ohme Smart charger.

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Koala
Posts: 200
Joined: Sun Mar 17, 2019 8:40 pm
Location: Germany - Bavaria

Re: TCU Battery at 5%

Post by Koala » Fri Jan 22, 2021 7:25 pm

ianipace wrote:
Mon Jan 18, 2021 7:18 pm
Koala wrote:
Mon Jan 18, 2021 6:38 pm
IynCognito wrote:
Tue Jan 12, 2021 8:27 pm
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.
EV400 S, MY2019, Firenze Red, Light Oyster Interieur, Acitve Air suspension, 18" Diamond turned Wheels.
IMC: S20C | TCU: 17.2 | 50.000 KM of happy I-Pace driving since March 14th, 2019

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