With newly built 12 volt relays you can simply use a very fast impulse with a negative or positive command to activate and keep a load of up to 20amp activated and then always turn it off with the usual impulse of a few milliseconds, and so on. To be used in direct current DC.
It is found in multiple uses from control units for competition on cars or on industrial vehicles such as excavators 01170716 and agricultural vehicles and nautical applications.