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The joulemeters used in the Shell Eco-marathon (Shell Eco-marathon) are custom built for Shell and are not available for purchase. The joulemeter (JM) measures voltage across the + and – bus bars and current through one of the bus bars. The JM calculates joules from measure of voltage, current, and time. The JM will be used in all Shell Eco-marathon energy classes to measure electrical energy flow. The JM includes a LCD display showing a number of measured values. Firmware in the JM measures the following;
|Dimensions||88mm wide x 108mm tall x 46mm depth (3.5” x 4.25” x 1.8”)|
|Voltage range||+ 0 to 60 VDC|
|Current range||+/- 0 to 300 A|
|Resistance of shunt||100 µΩ|
|Voltage measurement resolution (internal)||2 mV|
|Current measurement resolution (internal)||10 mA|
|Joule display resolution||1 J|
|Shunt internal temperature compensation||yes|
NON Battery Electric Prototype vehicles are not currently required to install a joulemeter.
Joulemeter location in vehicle and other considerations
The Joulemeter should be installed between the vehicle’s accessory battery and the vehicle’s electrical system. As shown in the figure below, both the positive and negative battery leads pass through the Joulemeter.
For urban concept vehicles the joulemeter should be installed between the battery and the propulsion motor controller. As shown below, both the positive and negative battery leads pass through the Joulemeter.
For prototype vehicles the joulemeter should be installed between the vehicle’s electrical system and the propulsion motor controller. As shown below, both the positive and negative battery leads pass through the Joulemeter.
The Joulemeter should be installed between the battery and the vehicle’s electrical system. As shown below, both the positive and negative battery leads pass through the Joulemeter.
To operate the JM, turn the on switch to the on position (Down - ON, up - OFF). As the JM powers up, the internal battery voltage will be displayed. The usable internal battery voltage range is between 3.5 VDC and 4.1 VDC. The JM will be supplied to teams configured to display the correct measured values.
The JM internal battery is charged though the USB B port on the JM top as shown in Figure 3. The JM will be supplied to the teams charged and should last through the event without being charged if the JM is turned off when not in use. If the JM internal battery needs charging, connect the JM to any USB port or charger and the battery will be charged. Although it is not required, the JM will charge faster if the JM is turned off. The message “Full” will be displayed on the JM when the internal battery is fully charged.
The table below provides a number of troubleshooting options for cases where anomalies are detected.
Please verify the contents of this section before seeking assistance from the organisers.
|The LEDs do not come on when I press the Start Button on the On Board Computer||OBC battery is not correctly connected to BackBone |
OBC battery is discharged
|Verify battery cable is connected on BackBone
|Pod not correctly connected to BackBone||Check cable and plug|