TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Starter: In the jump starter, the on-board starter battery means (15, 26) comprises a lithium iron phosphate battery. There is a set of on-board starter batteries (15) along the interconnection means. The on-board starter battery means (15, 26) comprises a set of separate batteries which are electrically interconnected. Also, at least some of the battery means comprises batteries (26) housed within at least one of the first and second handles. The batteries are housed within both the first handle (25) and the second handle (25). The first clip (56) and the second clip (56) are configured to nest together for storage in compact manner. The first clip (51) has a housing (55) within which there is a battery, and a pair of jaws (56) linked with the housing; and the second clip (52) is configured to fit alongside the jaws of the first clip in a manner without protruding parts. The first clip (51) has a groove (60) to accommodate the interconnection means (53) during storage. The jump starter further comprises a control circuit having positive and negative leads connected between the on-board starter battery and the clips, and protection means to provide over-voltage and/or over-current protection. The protection means comprises a current-limiting component. The control circuit further comprises a switch (Q1-Q3) in the negative lead which is turned on for use. The switch is a solid state switch, where the switch comprises a metal oxide semiconductor field effect transistors (MOSFET) switch. The switch is an SCR. There is a set of switches (Q1-Q3) arranged in parallel. A gate of the switch is connected to the positive lead by a user-activated switch (115, 215). The user-activated switch is of the type for momentary closing, where the user-activated switch is connected to the gate via a diode (ZD1), preferably a Zener diode. The switch is solid state and is reverse biased to prevent current flow if a system to which the clamps are connected attempts to return charge. The protection means comprises a circuit to short gate current to ground in the event of accidental reverse polarity connection. The positive lead includes one or more positive thermal coefficient fuses (10, 110) protecting against short circuit conditions and excessive power demands by achieving a very high resistance, thus limiting current flow, and once normal conditions are restored dropping to a low resistance. There is a resistor and a light emitting diode (LED) in parallel with the fuse such that if the fuse resistance goes high almost all of the battery voltage will appear across the resistor thus providing a current flow to illuminate the LED, and when the fuse is in a low resistance state and operating normally the resistor and the fuse are effectively short circuited, providing a visual indication of overload conditions. The positive lead includes a bank of switches connected in such a way as to utilize their intrinsic diodes for the purposes of reverse blocking of current, in which gate to source is short circuited, thus holding the switches in a permanent OFF state. An RC time constant circuit is linked with the negative lead switch or switches, the time constant circuit being arranged to set the run time of the jump starter and preventing the jump starter from being left in a constant ON condition. The time constant circuit is arranged to provide a soft turn on of the jump starter power, preventing transient voltage damage as a result of arcing or high di/dt induced voltages in an electrical system to which the starter is connected.