Sucks Windows 8 1 or what

Lenovo ThinkPad 8 sucks the battery empty in standby (full charge in under 24 hours)

Hello,

maybe someone of you has a tip for me here. we have several tablets with Windows 8 and Windows 10 in use. one of them is the Lenovo ThinkPad 8, which is now operated with Windows 10. Even under Windows 8, this device had the problem that the battery was sucked empty completely incomprehensibly in standby. If you put the fully charged device on your desk at around 6 p.m. at the end of the day, it will be half empty by 9 a.m. the next morning. However, the battery behaves completely normally during operation. so no excessively fast unloading.

first i thought of driver problems, energy saving modes, wlan, bluetooth and a few other things. but now I can rule out all of them. the device has also already been reset. We made a freshly installed Windows 10 out of the original Windows 8.1. the entire device runs like a dream - except for this problem.

The device currently has the following configuration:

energy saving after: 4 minutes
standby after: 8 minutes
wlan in standby: off
Bluetooth in standby: off
drivers are all correct, everything looks normal. but that can't be normal. If I leave other tablets like the Surface in the cabinet for two whole weeks, the battery is hardly empty than two weeks before, depending on the setting.

someone an idea what to look for there? can I rule out a hardware defect? As already mentioned, the battery behaves normally under load.

PS: I know that thinkpads often have strange settings when it comes to energy consumption. but what I have found so far are problems like "battery loses 5-8% overnight". with us that's 30-40% overnight.