The standalone lithium replacement batteries are the same size and have the bms built in... They are a direct replacement... Open the alarm box... Pull the spade connectors off the old battery, put in the new battery and put the spade connectors back on... Its a 5 min job at most
Lithium takes charge at a far faster rate than lead acid... Hence the better recharge time... In addition you can have a deeper depth of discharge without damaging the battery, so they are just better all round
Have used these in both ups and alarm system. Generally give you twice the backup time, and a fraction of the recharge time... Providing the charger is up to the task. So far no noticible change in performance after a couple of weeks of heavy use... Know its early days but happy for now. Hope it...