Batteries Sparky is equipped with eight 6 volt, 220 amp hour Concorde Lifeline deep cycle marine batteries. These are Absorbed Glass Mat (AGM) lead acid construction. AGM batteries have several advantages of standard wet lead acid batteries: 1) They are sealed so do not need water added periodically. This means the batteries do not need to be readily accessible thus permitting a more flexible interior design. 2) They have less internal resistance so are more tolerant of rapid charge and discharge. This makes more of the batteries total energy available at typical cruising speeds. 3) They have a much slower self-discharge rate so can be left untended for months without going dead. 4) Even without maintenance they last longer than conventional batteries. Concorde rates them for 500 cycles at 80% depth of discharge and 1000 cycles at 50% depth of discharge. They could easily last five years or more in normal service. Sparky has four batteries under the fore deck and four more under the cockpit table. Drive System Circuit breaker to isolate battery voltage from all electronics. Power current relay controlled by Sevcon PMAC controller. Sevcon PMAC controller. The throttle joystick creates an input signal for speed and direction. This device creates the three phase alternating current waveform to drive the motor in the intended speed and direction. It also has several safety features such as the motor won't start if the key is turned on when the joystick is not in the neutral position and the power will automatically cut back if the unit overheats. Sevcon 12/48 converter. This steps down the 48 volt battery output to 12 volts for the lights and stereo. Thrust bearing to support the prop shaft and take the thrust load. It is a self aligning hardened steel ball bearing with a composite housing designed to withstand steam cleaning in a food plant. Shunt to create a signal proportional to current flow - part of the Xantrex Link10 energy monitor. MARS electric motor. Designed for long life. No brush maintenance. The motor is 90% efficient at voltages between 24 to 48 VDC. Continuous current of 100 amps at 48 VDC. This is a 3-phase, Permanent Magnet Synchronous Motor with an axial air gap. Delta-Q Battery charger. Regular household A/C input, 1000 watt output to charge 48 volt battery bank. The charger is programmed by Delta-Q specifically for the 6v AGM batteries. It can be left plugged in indefinitely and can recharge the batteries (80% depth of discharge) in about 8 hours. The components are mounted on a ½" thick aluminum plate to provide rigidity and act as a heat sink. The plate is mounted to the boat's main bulkhead with three ½" dia stainless steel rods and rubber vibration isolators.