What charger do I use on a system with 2 bms in series

Hey so I recently acquired a mercane mx60 scooter that uses a 60v 20AH battery but the one I got was missing its battery and since I couldn't afford the 500$+ battery I took two battery's out of a couple of lime scooters each being 36v at 15AH connected the two battery's in series ducked taped them together and threw them in the battery compartment and the scooter runs perfectly no trouble at all made sure both were equally charged. My problem is that both batteries come with their own bms control board on top of them luckily as far as discharging them it seems that they work as 1 80v battery when fully charged if connected in series my question is do I connect their connect their charging cords in order to get them to charge as 1 battery and what kind of.charger do I use I want to avoid having to take them out and take them apart to charge individually if possible

xt60 charge-discharge port? get a xt60 parallel cord. then all you have to do is unplug the xt60s from the series connector ( I assume you made or bought a series xt60 cord) plug a 36V charger to the now paralleled 36V lime batteries.

Not sure how long the BMS's will continue working maybe forever might quit on you tomorrow.

84V is 11V higher Than the controller is designed for, so it too may quit on you. Then again it might last forever.
Later floyd