An additional device is used to monitor the state of charge
of the battery system. An e-meter independently measures
the overall battery pack voltage and DC current in order
to estimate the state of charge by integration with Peukert’s
Law. As the battery system is vital to the success of a solar
vehicle, the e-meter allows for redundant sampling of the
battery statistics to protect against failures. This device also
has an RS-232 interface and makes the battery pack singular in
having the only systems with a continual feed of data without
the need for external polling.