Amateur Radio Station KDOZW

1.8Mhz to 5.9Ghz

Amateur Radio Station KDOZW

QRP Power

  • View from the Front side
  • View From the top
  • View from the back
  • 2011 Suitcase 13Watt solar panel, portable power 400w inverter, Bitx20a 6W pep 20mtr XCVR with DDS VFO — Mike KD0ZW

Ready to run on emergency power during field day? How much power will you need? How long do you plan to operate? Is it going to be sunny? What’s going to take? Personally, I challenge my self to always be ready to operate anytime I wish or it’s necessary. Using alternative energy, and a quality deep cycle battery, you will be ready to run your station. Below is a quick analysis of the power required to run a minimal system and conclusions.

Assumptions: Run IC-7300 @43% power making approx 35watts output. Running 160W solar panels for 6 hours with 100% sun. We expect to be transmitting (TX) 60% of the time. Receiver (RX) specs for IC-7300 show a draw of approx 1.2 amps. The two (80W) solar panels in full sun should generate 12v @ 13 amps or about 156watts/hour. And the 400-watt inverter is about 90% efficient. Our Deep cycle battery is 12V rated at 60Amp/hr. Not to run down less than 50% of capacity. Using a PWM charger controller that can handle 20Amps.

Results: At any given time over the 6 hrs of operation the maximum hourly draw is approx 42 watts/hour for the IC-7300 and 44 watts/hour for the laptop. For a total of 86 watt-hours. This will require over 7.1 amps @12V from the power system. If we were just using a fully charged battery with our assumptions, the battery would be exhausted in 2 hours.

Adding solar cells: Adding 160w of solar energy to our system improves the situation. Our panel will contribute 12V @ 13 amps to run the radio and top off the deep cycle battery each hour. That’s the entire need for our IC-7300 system. So at the end of 6 hrs of operation, our battery should be fully charged and be able to deliver a couple more hours of energy without damaging the battery. Also, a 400-watt inverter could handle the load with ease.

Conclusion: I know we made the best case situation of 100% sun and the worst-case presentation of 86/watt hours from the system. However, suppose we got 50% from the solar panel, we would still have enough power to run 7 hrs. Also, steps can be taken to reduce laptop power demand. ie. Reducing the screen brightness. Bottom line: We can operate aggressively for 6+hrs. Running 100watts output, 12V@10 amps, would max our system for 6 hrs if we have a completely sunny day.