Do this first.
What? Wake Timers. DISABLE THOSE. Here's an article about it.
https://www.howtogeek.com/122954/how-to-prevent-your-computer-from-waking-up-accidentally/
You can read the whole thing but time after time it's been the wake timers.
i bought a laptop, and when the parcel reached, the battery was low as dead... i charged it though...now when i shut it down and leave it overnight, and turn it on the other day, it wakes from sleep, and has consumed a lot of battery... don't know if it is hardware or software problem... don't know what forces the computer to shift from shutdown to sleep mode

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