Table of Contents
Goals of The Monitoring System
- To prevent permanent damage to the energy bank from over-discharging our lead acid battery
- To be able to continuously charge the energy bank and provide power to P12402 team simultaneously
- To protect the charging dock system or (P12402 team) from high inrush current
- To display the level/capacity of our energy bank from 60% to 100%, so P12402 team can determine how many batteries can be charged.
- To be modular, so future team would be able to utilize the spared pins off the MCU, the MCU as well as the I2C peripherals.
This system consists of two different relays, a 40A and a 20A normally closed relay. The 20A relay is placed between the battery terminals and the output to the charging dock. This relay is needed to break the output connection in the event that the state of charge in the SLA battery falls below 60%. The 40A relay is located in between the Nature Power charge controller and the terminals of the SLA battery. This relay is needed in order to test the state of charge of the battery. The voltage of the battery, without the charge controller, needs to be tested in order to determining state of charge. The circuit will open the 40A relay, disconnecting any voltage coming from the wind turbine, and test the voltage provided by the battery alone. The circuit will then close the 40A relay and determining whether the 20A relay should remain opened or closed. This test period will be repeated on a regular interval.
The system, PCBA not included, will contain one 7.5A fuse at the output of the battery and a circuit breaker in between charge controller and battery terminal. The 7.5 A fuse is placed in order to protect the P12401 Charging Dock. The circuit breaker will trip when the stop switch is enabled so that the battery terminals are not shorted together.
The Nature Power turbine also comes with a stop switch. Under normal conditions the stop switch will connect the positive Nature Power charge controller terminal to the positive terminals on the battery. When the stop switch is enabled it will short the terminals of the charge controller and the controller will place a load on the wind turbine and stop the blades.
The power to the PCBA will be provided through two barrel connectors. The first connection will provide power from the terminals of the battery and the second connection will provide power from the Nature Power charge controller. The use of two power sources is necessary to power the PCBA in the event where an empty battery is inserted and there is not enough power to close the 40A relay.
The PCBA will also control the state of the relays. The PCBA will output a signal of 12 volts to close a relay and will output 0 volts to open a relay.
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Electrical Drawing Files for the PCB
Mechanical Drawing Files for the PCB
Bill of Materials for PCB Only
See the specific Bill of Materials for the Printed Circuit Board below.