9
OVERVIEW
Installation. PowerMon-5S was designed to be installed inside an equipment bay, or inside a plastic
enclosure where it will be protected from water, high humidity, condensation, and battery or other corrosive
gases. The device should not be installed inside an all-metal enclosure since that will significantly reduce the
Bluetooth range. Only one screw is required to mount the device on a flat surface. The second mounting hole is
partially obstructed by the circuit board. If mounting using both holes is required, the circuit board can be
removed. Pay attention to re-install the two washers between the shunt and the circuit board. Failure to do so
will result in a short-circuit that will damage the circuit board. Thornwave Labs does not take responsibility for
damage caused by removing the circuit board. Use the enclosed black wire to connect the battery negative to
the left side terminal. Use the blue wire to connect the right-side terminal (RELAY) to the relay coil (if a relay is
installed).
Device power. The PowerMon-5S device is drawing its supply power from the BATT+ / BATT- terminals.
Power should always be present. If the device loses power, it will forget the internal clock.
Integrated current shunt. All loads and charging sources should be connected to the LOAD terminal. The
shunt is rated at 500A / 0.25%. The shunt is can only be installed on the positive side of the circuit.
Zero the current offset. Due to the high sensitivity of the current measurement circuitry inside the
PowerMon-5S device, the value displayed may have a small offset (measurement is different than zero even
when the actual current is zero). Typically, this is less than 0.1A. In situations where the measurement precision
is critical, the offset can be reduced to zero. To do this, disconnect the wire from the load side of the shunt or
make sure the actual current is zero (turn off all the loads). This can also be achieved by turning the power relay
off from the application (in case the system is wired with a relay). Long-tap on the “Current” tab and then “Zero
Current”. The operation will take 3 seconds to complete during which do not allow any current to pass through
the device. Also, do not zero the current offset if the actual current is greater than zero. Doing so will introduce
a very large offset. Any current that is flowing through the shunt when the Zero Current operation is performed
will become the new indicated zero.
Current calibration. Typically, the device can measure current with better than 1% precision. If higher
precision is required, the current measurement can be calibrated allowing up to 0.25% of precision. To calibrate
the current reading, an amp-meter capable of measuring current with a precision better than 0.25% is required.
Connect the amp-meter leads in series with the shunt and read the actual value of the current. Long-tap on the
“Current” tab, tap on “Calibrate Current” and then type the actual value measured by the amp-meter. The sign
of the current does not matter. Once calibrated, the only way to change the calibration is to reset the device to
factory defaults or re-calibrate. The device will not accept a calibration current different from the actual current
reading by more than 10%.
