S63 Power issues - red battery warning - shutdown

Hi,
so I have a main issue which was caused by another small issue.
Backing out my car, noticed smoking coming from passenger side engine bay. Shut car down, opened hood saw some coolant sprayed and was burning off. Not a lot. Tightened cap and secured hoses, no more leak.
go to drive off and after minute or so I get error on screen - battery see manual. I was able to drive to lunch back to work and then home. When home and checking car out systems in car become non operational until all screen shut off, can’t even turn car off have to wait till it dies on own.
Not sure my culprit.
Don’t think it has to do w my main battery
possibly the capacitor blew
or somehow alternator went out at that exact moment, or because of coolant spray.
Thoughts?
Car has no power, nothing works. opened trunk at hooked up battery charger and car attempts to power for few seconds before shutting off and doing nothing again.
Thank you for your time in advance, I appreciate it greatly!
-Dave






