Idk who told you that but you always want the BMS between your
battery and ANY device. It protects the
battery from damage.
Solar > Controller > BMS > Battery.
If you read the
battery manual page 4 the batteries only disconnect under Over/ Under Voltage conditions that would damage the batteries. If you never exceed a range of 8.0V to 15.6V the battery will be fine. Your solar controller should be setup to charge up to 14.4V and no futher. The controller is smart enough to stop
charging.
Balance your cells (If not already) configure your
charger for
Lifepo4 batteries and go.