Esp8266 relay for 42V battery cut off -- 2

Budget:30$,Need to have atleast 5 years experience in Electrical and Electronic engineering who worked with electric scooters. Battery is 36v,max current is 42V. Can send you video and pics of scooter or live video sharing to show the product. Need to know how to battery on/off using relay and [login to view URL] in wiring to relay to control. Have all code for nodemcu etc ,need to find out a way where we can control wires for battery which is going into controller board. Relay and mcu is blowing up after sometime. Need to fix relay and add transistor so that it does not blow up and blow controller board. Need to provide schematic and wiring ,need to help if any problem during assembly and testing. it should be perfectly working 24x7 It should not take more than an hour to provide solution for [login to view URL] best solution. More tasks will be given and looking for long term relationship.