Weird issue on my Windsor EV: Car loses charge while parked!

The calculation shows that 1% charge loss per 3 hours of a 38kWh battery means something(s) are consuming about 127 Watts continuously.

BHPian deb_majumdar recently shared this with other enthusiasts:

I am facing a sort of parasitic battery drain for the last one week. I have discussed the issue with a few other new Windsor owners, and it's time to share it with the larger community.

Since last Sunday morning, I noticed that the car is losing about 1% charge per three hours when parked. It did not happen during the first 10-12 days; I had the car unused for more than 24 hours without losing any percentage then.

If I remember correctly, a battery discharge warning started coming up sporadically before last Saturday (but I am not sure). Since I have noticed this issue, that warning shows up every time I open the driver's door after the car has been off for a while. I have tried various combinations; used the 'P' button on the gear stick / used the manual switch off button below the steering, ultimately the same result and approximately the same amount of HV battery drain (4% in 12 hours).

Scanning the vehicle using the iSmart app, I have observed the following about the LV battery voltage.

After the car is driven for sometime, the voltage is 12.6-13V. After parking the car, the voltage drops for some time. I have seen it drop till 12.1V. But after that, it becomes 14.4V and remains so as long as the car is parked. I read up a bit and figured that the voltage should show 14.4V when the LV battery is actively charging. [ Note: during the first few days, the battery used to show 12.6V, not 14.4V. ]

This means, something remains on in the car, the LV battery runs it. When it drains itself, the HV battery charges it. Some EV cars have this feature (Windsor does) -- which is a good thing, otherwise every night I would have ended up with drained LV battery.

Another curious thing -- not sure if it's related. When I scan the app, it shows "park brake: on". I remember seeing "park brake: off" during the first few days. I was worried the first time I noticed it and went downstairs to check whether I have put the car in P mode. Strangely, it showed "off" when everything was okay. For other fellow BHPians too, it shows "off". I cannot remember very well, but ever since I have noticed the battery drain issue, I also see the park brake showing "on".

As I went to get my number plates yesterday, I met the "EV expert" of the service centre. He did not want to acknowledge that it is even a problem, he said it is normal. He showed some document pertaining to Comet, the document says a drop of 2% per 8 hours is acceptable due to the HV battery charging the LV battery whenever needed. I had a kind of argument with him, I explained that 1% in 3 hours of Windsor means a lot more charge than 1% in 4 hours in Comet. Besides, this was not happening for me initially and none of the other owners are having this issue. He said he can work on it only if I keep the car with them. I really need the car next week, so I will probably get the 1000km service done mid next week, but let them have the car for solving this problem from 25th of November onwards.

The calculation shows that 1% charge loss per 3 hours of a 38kWh battery means something(s) are consuming about 127 Watts continuously.

I would be curious to know if anyone else has faced a similar problem yet.

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