In this Video Alex talks about the process of swapping out his lead acid leaure batteries for a Lithium phosphate subsitute. From a technical aspect having the BMS built into a battery is going to make for a much simpler installation. The downside is these batteries are often more expensive than buying your own cells and using an external BMS.
TIPS AND COMMENTS
"Plug And Play"
Don't fall into the trap of thinking a 12v lithium battery will be a straight swap for lead acid. In fact,lithium has a higher charging voltage. Using the wrong charger will overcharge your battery cells, potentially causing the BMS to go into cell overcharge protection mode. You can mitigate this by double-checking the charge and float charge of your smart charger, mppt or inverter charger. Some chargers allow for a custom setting to be entered. There are numerous debates online about what the Float charge of a lithium battery should be set at.