If you charge the battery connected to the charger it cold surge the power going to the other electrical and cause more problems in the other components. Some chargers charge at a higher rate then the components need, causing a surge.
I disconnected it and thank you. I knew I saw that somewhere just didn't see it in the manual. My diagnostics showed the battery is either toast or needs to be reconditioned. I'm reconditioning it now but figure on needing a new battery. The prior owner was not aware of the large battery disconnect switch.