RS6 electronics and battery management

[IchBautAuto]

Came across this on my CTEK battery sense monitor. The car has been sitting for 8 days since I returned from a small trip. The battery has been steadily discharging but using the app algorithm, it has not been losing excessive power (measured as battery percentage of capacity). Yesterday around 1700 I unlocked the car and left the drivers door open for about an hour while I installed the alloy pedals. The resulting battery capacity graph is quite interesting.

You can see the voltage drop as the door opens and the interior footwell lights come on. You can then see the small kick as they extinguish after 5 mins or whatever it is. For about the next 6 hours the battery is still subject to an extra load before slowly recovering over another 6 hours and overshooting before stabilizing again.

I'm sure that there will be some amendments to be made to this when I know a bit more about the app, like how often readings are taken and recorded, but I did find it interesting how long it seems to take to return to a steady state. What and for how long draws current in this car when it otherwise not being used is quite amazing. The RNS-E upgrade is a prime suspect now that I have removed the alarm siren.

[Mark-RS]

I have converted all my interior to LED. I'm assuming these would use less juice ?

[Hixrs6]

Isn’t that fairly normal for leaving lights on etc. The battery gets recharged once it’s being driven so as long as there’s enough cold cranking amps to turn the Engine over you’re fine

[IchBautAuto]

Isn’t that fairly normal for leaving lights on etc. The battery gets recharged once it’s being driven so as long as there’s enough cold cranking amps to turn the Engine over you’re fine

For sure. The interior and footwell lights are only on for 5 minutes or less and my interest was more in the length of time "something" in the car was powered up before finally shutting down and allowing the battery voltage to rise again. Exactly what the cars computers are doing behind the scene while the car is laid up is still a mystery to me.

There is a point where the alarm system ceases to function once the battery voltage gets below a point, at least that's what mine did. Maybe 11.6 to 11.8V. That was what alerted me to the battery voltage drop issues around the beginning of this year.

I regularly use a trickle charger now so I'm not going to get to the position where my battery is marginal for a start. Just can't leave it on daily as it constantly illuminates a P3 gauge that is voltage dependent.