A portable drawn arc stud welder apparatus for welding a stud onto a workpiece, the portable drawn arc stud welder apparatus including: a housing ; a battery disposed in the housing and; a weld stud gun configured to hold a stud electrically connected to the battery for receiving energy from the battery to pass a current through the stud and the workpiece to form a weldment; a stud weld battery control system (SWBCS) disposed in the housing electrically connected to the battery of the portable drawn arc stud welder apparatus , wherein the SWBCS includes a computer, a processor, and a memory, and instructions therein, to implement control and monitoring of the operation of the portable drawn arc stud welder apparatus ; [ - ] the SWBCS is configured to measure the rate of change of a voltage of the LFP battery after a sequence of consecutive welds and to determine whether measured the rate of change exceeds a predetermined rate of change level; [[ - ]] the SWBCS configured to activate one or more fans disposed in the housing at least if the measured temperature of the LFP battery exceeds a predetermined temperature level and/or if a calculated welding rate exceeds a predetermined welding rate and the SWBCS configured to selectively operate the one or more fans at least if the measured temperature drops below the predetermined temperature level and/or if the calculated welding rate exceeds a predetermined level. [ characterized in that the battery is a lithium ferrophosphate (LFP) battery including a plurality of LFP battery cells ; ] [[ the SWBCS is configured to balance the levels of voltage and current of the plurality of battery cells and then measure a temperature of the LFP battery via temperature sensors against a predetermined temperature range at least after the SWBCS balances the levels of voltage and current of the plurality of battery cells; ]] a housing ; a battery disposed in the housing and; a weld stud gun configured to hold a stud electrically connected to the battery for receiving energy from the battery to pass a current through the stud and the workpiece to form a weldment; a stud weld battery control system (SWBCS) disposed in the housing electrically connected to the battery of the portable drawn arc stud welder apparatus , wherein the SWBCS includes a computer, a processor, and a memory, and instructions therein, to implement control and monitoring of the operation of the portable drawn arc stud welder apparatus ; [ - ] the SWBCS is configured to measure the rate of change of a voltage of the LFP battery after a sequence of consecutive welds and to determine whether measured the rate of change exceeds a predetermined rate of change level; [[ - ]] the SWBCS configured to activate one or more fans disposed in the housing at least if the measured temperature of the LFP battery exceeds a predetermined temperature level and/or if a calculated welding rate exceeds a predetermined welding rate and the SWBCS configured to selectively operate the one or more fans at least if the measured temperature drops below the predetermined temperature level and/or if the calculated welding rate exceeds a predetermined level. [ characterized in that the battery is a lithium ferrophosphate (LFP) battery including a plurality of LFP battery cells ; ] [[ the SWBCS is configured to balance the levels of voltage and current of the plurality of battery cells and then measure a temperature of the LFP battery via temperature sensors against a predetermined temperature range at least after the SWBCS balances the levels of voltage and current of the plurality of battery cells; ]] <EOS>