Agree! These things are a bit particular about the battery and what is happening back there. Recently I have needed to connect/reconnect because of trickle charger problems with a little aftermarket controller board which shall stay anonymous for now (after we know something worth it, I’ll share). I agree, I went in once and the fan only had low and high and no speeds the options were so limited for a while. But, true it does clear up with time.
Quick moral, little trickle chargers like we use on our motorcycles, may not be so good attached for several months. It may be better to just put a big charger on these cars every month and charge it up quick.