I’ve been able to solar-power a small ham radio station for about two hundred dollars. The radios in this setup have relatively modest power requirements:
- Elecraft KX-1
- Kenwood TH-F6A 2M/440 handheld
Here is a diagram of the station’s power supply:
The solar panel is a small 20W panel purchased from EcoDirect.com for $56.95 (Model VLS-20W). It is large enough to operate the KX-1 and charge the TH-F^A continuously (when there is sunshine) and keep the battery fully charged.
The charge controller is the Morningstar SG-4 PWM 4.5A Charge Controller. This is a PWM controller so it is less efficient than an MPPT controller but in this low-power application it will be just fine. It also cost only $25.75.
The battery is a 7.5Ah Gel CEll. I purchased mine from BatterySpace.com for $18.80, but these can be found anywhere. In this application, there is nothing magic about the capacity (7.5Ah). You’ll reliably and repeatedly get 4.5Ah out of this battery. (For an explanation of why 4.5 instead of 7.4 Ah, read this post.) It contains enough charge to operate the KX-1 for about 6 hours.
Why didn’t I use a Lithium battery, you ask? Lithium batteries, preferably Lithium Phosphate (LiPo) are much smaller and lighter. However, most charge controllers are intended for use with gel cell batteries. Lithium battery packs also need charge-balancing periodically.
The Power Meter/Analyzer is from Turnigy. I bought it from Powerworx.com (the ANderson PowerPole people) for $59.99.
Why a Wattmeter / Power Analyzer? The meter operating inline continuously allows me to keep tabs on the battery voltage. It is really important to avoid discharging the battery below about 11.9V (Click here to learn why). It is also useful for measuring the actual current draw of the radios (as well as the output fro the solar panel and charge controller). This particular meter comes with Anderson Powerpole connectors already installed.
All connections use Anderson Powerpoles. The more I use them the better I like them.
The Elecraft KX-1 draws about 700mA on transmit and 30mA on receive. For the Kenwood TH-F6A, I use its own internal batteries and recharge them from the 12V Gel Cell. The TH-F6A draws about 300mA while charging.