Crydom lvd75b40 solid state battery protection relay panel mount crydom lvd75d40 a solid state relay with a 3 to 75v dc operating voltage load current is 40a and the control voltage is 23 to 24v dc designed as a battery protection relay for 12v and 24v dc battery systems crydom lvd75d40 solid state relay 75vdc 40a max 23 24vdc control voltage