I watch the youtube video, in it he mentions to use the bms to control the charging and the "victron battery protect" to control the discharging.
The bms should bethe last line of defense in casethe charging system doesnt stop chargingor battery goes out of balance during charging. The controller if it is in the proper setting will hopefully not let the battery get too high. On my system I have an overvoltage protection relay that will trip if the battery voltage gets too high. You never want the bms to stop the charging, thats when the battery is disconnected from the controller (while still connected to the panel), I think that is what he mention about the controller being destroyed. Mine never got destroyed but you get the controller cycling back and forth and voltage surges which can destroy equipment that is connected to system. I lost many fans and pumps from voltage surges.
overall voltage charging (recommend active balancers to keep battery in balance)
1. solar controller (set low enough so battery never reaches full charge triggering bms)
2. overvoltage protection relay (set to disconnect panel at voltage below bms activation)
3. bms (only activates if above 2 fails, will cause voltage surges if activated)
Since your system is relying on overall voltage to control charging I highly recommend active balancers, these will keep the battery in perfect balance so overall voltage is always accurate.
active balancers I use, the 4s model cost 92 dollars. This is the only way that you safely charge using overall voltage. Lithium batteries have a tendency to go out of balance when fast charging near the top end. These balancers balance at up to 6 amps, they can keep up when your charging at higher amps. If the bms trips early to stop charging you will never get a full charge and your controller will be producing voltage surges.
This a picture of the chargery bms8t I use, I paid 86 dollarsfor it, this is the best bms for solar that I found. balances at 1.2 amps, SOC, lcd screen, audible alarms, 2x temp sensors, programmable cutoffs, amps is only limited by the size of your mechanical relay. With this bms and overvoltage protection relay you can leave system running 24/7 and rarely need to do adjustments.
To use one bms, just connect both of your 8s batteries together with y connectors. The main power connectors, and the balance connectors, once connected the batteries will equalize and you will have a giant battery. Connect the bms to this battery. Just make sure both batteries are the same voltage before connecting together. Thats how I have my 220ah battery connected, its actually 2x 110ah 4s20p lifepo4 connected together.