It missed us by 9 days

What would be the effect of a solar storm on a totally off grid system with Nissan Leaf G1 Li-ion Battery Banks inside a building?  

In this case the building is a 40 foot long thick aluminum roofed tour bus with Stainless steel sides with tires so there is no direct to earth ground.

Last summer we did have unexplained intermittent controller shut downs with no error codes, were there large solar events in the summer of 2021?