Power Supply

The Senquip QUAD has been designed to offer maximum flexibility in terms of power supply requirements and is able to run off permanent power and solar.

Permanent power

A wide input range of 10-75V operation allows for use in automotive, industrial and telecoms applications. System power is backed up with an internal lithium polymer rechargeable battery in the event of power outages. Supply voltage is monitored to a resolution of 100mV and can be reported on a periodic basis if enabled.

The supply voltage input is reverse polarity protected and is resistant to damage from static and surge.

Parameter	Specification
DC supply voltage range	10V to 75V
Hibernate voltage	9.5V

The Senquip QUAD can be used with a solar panel as a source of power. When used with solar, an internal LiPo backs the device up overnight and during cloudy weather. When running on solar, the panel needs to be able to collect enough energy during sunlight hours to power the device through the night and on cloudy days. Keep in mind that solar panels will tend to get dusty and so should be over-rated to avoid regular maintenance. A typical 12V solar panel used to power the Senquip QUAD along with it’s specifications is shown below:

Typical solar panel — Typical Senquip QUAD solar panel

Parameter	Specification
Maximum power	10W
Voltage at maximum power	17V
Current at maximum power	0.56A
Open-circuit voltage	21.6V
Short-circuit current	0.68A
Width	357mm
Height	302mm

The above solar panel was tested with a Senquip QUAD measuring and reporting 2 input voltages, ambient temperature, ambient pressure and thermocouple temperature at an interval of 5 minutes. To conserve energy in what was a fixed location test, GPS location was measured every 20 base intervals or 100 minutes. The results were transmitted over 4G LTE or Wi-Fi at 5 minute intervals. The solar panel was sufficient to power the Senquip QUAD.

Internal rechargeable battery

An Internal 3.7V, 1800mAh rechargeable Lithium Ion Polymer (LiPo) battery is charged from system power, making the device ideal in applications where power is intermittent such as solar. The LiPo battery can be fully recharged within 4 hours of system power being connected.

If the internal LiPo has been allowed to completely discharge; when power is first applied to a Senquip QUAD, the battery will go into a pre-charge mode where the battery is charged to a minimum level before the device starts operating. Pre-charge mode is identified by a slow flash on the green LED with the orange LED off.

An internal protection circuits prevent damage to the LiPo battery in the event of a short circuit or due to excessive discharge. A temperature monitoring circuit terminates LiPo battery charging at temperatures below 0 °C and above 45°C. It is recommended that the LiPo battery be replaced after three years of use or more regularly if the device routinely operates in extended temperatures. The LiPo battery should only be replaced by a Senquip replacement part and should only be installed by a suitably trained technician.

System voltage which is closely related to the LiPo battery voltage is monitored to a resolution of 100mV and is reported at the base interval.

State	AA Batteries	External Power	Comment
LiPo charge threshold	3.7V	4.108	The voltage below which a charge cycle is initiated
LiPo precharge voltage threshold	3.6V	3.6V	Slow flash on green LED, device not operational below this value
LiPo charging voltage	4.208V	4.208V
LiPo charging current	150mA	300mA
LiPo charge current termination	128mA	128mA	Charge terminates when charge current below 128mA and battery voltage is above the charge threshold
System shutdown	3.6V	3.6V	Device enters freight mode
Minimum input voltage for charging	4.1V	10V
Maximum current from charge source	150mA	500mA	Not suitable for Lithium-thionyl Chloride batteries
Safety timer	8 hours	8 hours	Time after which charging will cease
Charge temperature range	0 to 45°C	0 to 45°C	Charging will terminate outside of this range
Operating temperature range	-20 to 80°C	-20 to 80°C	Charging will terminate outside of this range

Power consumption

The Senquip QUAD has been designed to be suitable for use in applications where permanent power is not available and solar and other sources of intermittent power are the only source of energy. Factors affecting power consumption include the rate at which sensor measurements are made, the number of transmissions of measured data and which internal and external sensors that are connected.

Broadly, the state of the Senquip QUAD can be divided into three modes: sleep, measurement and transmission. Sleep mode is by far the lowest power state where most internal sensors are turned off and the device is waiting for the next measurement period. During a measurement period, the sensors are turned on and power consumption increases dramatically. The actual power consumed during a measurement phase depends on the power requirements of connected sensors and the duration for which they are turned on. For instance, a 4-20mA pressure sensor will, by default, draw between 4mA and 20mA of current when turned on. The sensor will clearly use less energy when measuring 4mA than when measuring 20mA. Transmission is the most energy intense operation performed by the Senquip QUAD. During transmission, the Wi-Fi and or 4G LTE radios are turned on and data is transmitted. Limiting the length of radio transmissions has a significant impact on energy consumed.

The following strategies can be used to limit power consumption:

Limit the rate at which measurements are taken - if the parameter being measured changes slowly, then measuring it regularly will consume additional energy without a benefit.
Turn off sensors that are not required - the Senquip QUAD contains a rich set of internal sensors. If for example, the GNSS is not required, turn it off.
Choose external sensors carefully - a 4-20mA sensor may use more energy than a voltage output sensor.
Limit the number of daily transmissions - consider only transmitting data when warning and alarm conditions are breached.
Ensure that the device is placed in a position where 4G LTE, Wi-Fi, and GNSS reception is optimal. Far more current is consumed when transmitting and receiving in a poor signal environment.

Measured sleep, measurement, and transmission current is given in the table below. The measurements in the table represent current flowing from the internal LiPo battery at 3.5V, with external power to the device removed. Except where stated, the GNSS is assumed off. Actual values will depend on the power source, selected measurements, battery charge state, distance from Wi-Fi or 4G LTE source and temperature.

Mode	Current	Time
Sleep	65uA	Up to 24 hours
Measurement (no external sensors, GPS off)	40mA	0.5s
Measurement (no external sensors, GPS cold start)	70mA	54s
Transmit (WiFi from sleep)	97mA	8s
Transmit (4G LTE from sleep)	120mA	20s

Freight mode

When shipping a Senquip QUAD, it is important that the device is placed in freight mode. In freight mode, the device is put into sleep mode to reduce battery drain to the minimum, and all transmitting devices are turned off. The Senquip QUAD will exit freight mode when it detects that power has been re-connected.

To enter freight mode access the device webserver by pressing the setup button or directly from a browser if the webserver is always on. From the webserver, chose the admin link and perform the steps below:

Disconnect all wires including the power input.
Press the ‘Enter Freight Mode’ button below.
Wait 5 seconds, then check the Status and Network lights remain off.
Confirm freight mode has been entered by pressing the Reset button; there should be no response from the device.

Note

A shortcut is provided where pressing the Setup button three times, when in setup mode, will cause the Senquip QUAD to enter freight mode. Confirm freight mode has been entered by pressing the Reset button.