Step 1: Power Requirements

We prototyped one system for this installation. The power requirement for this system is detailed below. It is important to not only understand the power consumption, but also the various voltage breakdowns and their associated power requirements. Additionally, it is important to acknowledge the fact that we want 24x365 uptime.

Step 2. System Diagram

This design benefits from the wide input range of the radio (no dc-dc converters) and the fact that the radio is capable of 23 dBm output (no amps required). As a result the design is much more simplistic and lower cost then the lucent designs described before. Also the lucent systems were over designed by a factor of 2, this system is not as we have gained implementation experience.

Below is a basic schematic diagram for a solar power system. Most loads should have a DC-DC convertor on them to adjust and regulate the voltage coming from the batteries. However, this particular radio has an extremly wide voltage input range (below 10 volts and up to at least 18 volts) so it can handle the entire operating voltage range of the battery (from over charge conditions to under charge conditions. Since we have a LVD (low voltage disconnect) and HVD (high voltage disconnect) capable charge controller, the voltage ranges on the battery will never exceed the acceptable range for the radio. It is also very important to think about the voltage of the solar array and batteries as higher voltages tend to lose less power due to wire resistance (however, we choose 12 volts for simplicity). HVD is designed to protect the equipment should the batteries be disconnected accidentally and to prevent the batteries from over charging. LVD is to protect the batteries so they will not be completely drained (it then reconnects the load when the batteries get recharge to a high enough level).

Step 3. Components

Below is a list of components we selected for our setup. Many solar companies have programs to calculate how many solar panels / batteries you need. They require several specific pieces of information:

• Approximate Location (lat/long, elevation): N33.3 W116.9, 5000 feet
• Continous Power Drain: 5.00
• Prefered final output voltage(s): 12v
• Physical Issues (pole-mount, roof-top, etc.): Pole Mount 2" pole or greater (side of pole mount) - we got it to mount onto a Rohn 25G as well

Additionally, we chose to go with a combined charge controller and load controller as opposed to aquiring each part individually.

In addition to this, you have the cost of the radio, the antennas and lmr-400 cable.

Step 4. Final Design Diagrams

Implementation 1: Low Power

The work on this project was completed by Todd Hansen for ROADNet and HPWREN.

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