-It protect your charger and BMS from reverse polarity
-It allow the cycle analyst to count the charged Ah
-No KFC risk... the fuse just blow
-no complicated main connection when using or charging the battery
- give you 12V for LED lamp, fan blower, or to power the low voltage rail of your kelly controller, etc
- allow to use a low current switch
The EV200 are availlable on ebay for about 40-50$ and can take up to 500A and 900Vdc and only consume 1.7watts with their integrated coil economizer.
The Dc-DC can be a simple 12V 5A switching power supply availle on ebay for about 10$