What you are encountering is SMC going into a locked state so it won't let you startup the next time as it has a serious failure condition. So now we need to discovery what SMC sees but fails to report to you.
You'll need to reset SMC a few times here. This time just disconnect the battery, then with nothing plugged in, press and hold the power button fo a good 15 secs to fully discharge the logic board. Now do the following:
So lets startup with checking the battery and the charging logic. Install this gem of an app! [https://www.coconut-flavour.com/coconutbattery/|CoconutBattery] take a snapshot of the apps main window and post it here for us to see [guide|21499]
Next let's run the onboard diagnostics press the ***D*** key after clearing SMC, did you get any errors?
References:
* [https://support.apple.com/en-us/HT201255|Mac startup key combinations]
* [https://support.apple.com/en-us/HT202731|Use Apple Diagnostics to test your Mac]