I understand. The charging system has to be up and running before you apply any kind of a load to it.
Just get use to the idea.
I have to be able to operate off the grid for as long as 8 hours at a time. My 1.2kW inverter will have a SHIRT-hemmorage if it wakes up to a motor load. Killed one already. I always, always start the inverter, then add the load. Not fun at 3AM but I can go back to bed in a wild winter storm and sleep well.
So. Plug in the charger, get it humming along. THEN add the load = the battery to be charged.