How can I operate a wireless modem off the grid?

Jesse Rothschild

The intelligent wireless gateway and router, often referred to as a wireless modem, is perfect for connecting where there is no wireline data available. Therefore it is logical to connect the wireless wide area network modem where there is no grid electric readily available as well. The solution is to harvest energy from the sun using solar photovoltaic cells. Wireless gateways use very small amounts of electricity, and they often run on DC power, the same direct current electric we can generate from solar PV arrays. USAT architects and assembles single panel systems designed to use a pole-mounted panel, a NEMA enclosure, and a battery array to power a wireless modem and connected equipment.

It is important to consider what equipment will be attached along with the wireless modem/intelligent gateway. Consult with your USAT sales representative before selecting the attached equipment as disparate voltages, native AC powered devices, and high draw equipment can force the solar assembly to be oversized and cost-prohibitive. For example, if you need to attach an IP Pan-Tilt-Zoom camera to the off-grid system, USAT can suggest low current PTZ cameras that work well with solar assemblies.

A similar example is with network switches. Switches designed for 12Vdc or 24Vdc or POE systems should be selected, and these should be rated for a broad operating temperature, for example -40C to +60C. Other equipment frequently used are radar, sensors including pressure sensors, accelerometers, humidistats, temperature sensors, digital signage, and devices attached to RTC (real-time control) type controllers. Cisco routers that rely on the Cisco Wireless HWIC are generally not optimal for off-grid deployments due to their energy requirements.

USAT has modeled the solar design characteristics for wireless gateways and modems including the Sierra Wireless AirLink® Raven, Sierra Wireless AirLink® PinPoint, Sierra Wireless AirLink® GX-400, Sierra Wireless AirLink® GX-440, Encore Bandits, Cradlepoint COR and MBR, Digi Connect, Digi WR, and Digi Transport.

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