Battery¶

Overview¶

The Battery will be of large capacity to provide power for up to three light bulbs, potentially for several days. For the prototype, it is simulated by a small lithium-ion battery. The pack will have to be smart so an mbed microcontroller is included to measure and report usage. There are three modes: 1. Charging in the locker at the base station 2. Powering appliances 3. Idling

Functions¶

Charging¶

1) Power & Energy a) The current level of charge b) How much power has gone into the battery in this cycle c) The current power going in d) Estimated time left until fully charged 2) Transfer usage data to base station

Powering¶

1) Power & Energy a) The current level of charge b) How much power has been supplied c) The current power / voltage / current out d) Estimated time left until empty at current rate of consumption 2) Data Logging a) Rolling averages of power out & voltage b) Total time in use c) Total time idling 3) Interface a) Display the current level of charge as colour on the led. 4) Data saving a) Force the battery into idling mode when it is nearly empty.

Idling¶

1) Display current level of charge on demand, e.g.: button press.

Technical implementation¶

green-current resistor red-potential divider for amp inputs cyan-instrumentation amp yellow-voltage sensor Circuit Diagram

Board Layout