Weird thing happened to my 2012 CLS63

Knowing my battery was low I proceeded to connect a smart trickle charger at the jump posts under the hood and turned it on...it stayed at 13.2 V the entire time until I got it started. However, the error message didnt go away.
I drove the car to the local MB dealer and they said that I blew the charging block/component by having the key in the ignition when I started charging it. They also said that warranty will not cover it and I have to pay $300 for the part plus labor.
My issues is that the power steering message came up before I connected the trickle charger and why would a low (not dead) battery cause the power steering to go out?

Has anyone dealt with this before?
i hope that it gets better for you!






