Unfortunately, this kind of statements are the reason that nobody wants to make charging systems for Zero motorcycles.
I have a homemade charging system for sale posted on the Facebook group ,and when I read the questions/comments/warnings from the people that, probably, don't even know what a BMS is, but they do have opinions, I don't know if I should laugh or cry.
Yes , the charger have to be properly setup with the proper parameters for the Zero battery pack.
I agree, the contactor shouldn't have to disconnect the battery from the charger, but my point is that your statement about mandatory communication between the BMS and charger, and fire hazard was wrong. Don't forget that the OEM Quick Charger sold by Zero has no communication with the BMS, just a charge enable signal.
If people are buying a charging system that doesnt have any communication with the BMS, and they dont even know what a BMS is, they shouldnt buy it in the first place. I also never said it was mandatory, but you should be aware of the conditions you are charging in if it doesnt. Case in point - I was charging at .6C yesterday after a hot day of riding and kept an eye on my pack temp - it went to 111F, I manually tapered down the current and the temp dropped. Per Zero's guidelines, charging should be tapered starting at 109f.
Also I'm 90% sure the delta-q charger is in bidirectional communication with the bike but I cant find any writing about it; Its not canbus but the 2 center aux pins provide a signal (I have verified this with an oscilliscope when charging and not charging). For example the procedure to charge with a delta-q charger is to key on to enable the contactor, plug in the delta-q to charge and key off. The contactor will open below 32f as its safe to ride but not charge, and if the delta-q provided a charge anyway, it would immediately start plating the battery. I couldnt find anything in wiriting, but the delta-q has to receive some kind of 'not okay to charge' signal from the bike, Zero would be insane to not do this.