A Kill-A-Watt for CQWW

Contrary to what many believe, solar power is not economical – but I’ve been wanting to experiment with it for some time now and a friend recently gave me a new mono-crystalline 70W solar panel. This provides the added benefit of allowing me to justify the purchase of a 100AH deep cycle battery.

Buying a spare power supply for the shack is something else that’s been on my mind due to my Astron “crow-barring” a few months ago. But an Astron 35M runs $200 and the battery costs half that – and now I can recharge it for free.

Although I don’t anticipate using the battery for this weekend’s contest, it’s there if I need it.

But first things first:

What I will be doing during the contest is measuring my power consumption as a first step toward learning what may need to be added to my 70W panel to make the station entirely solar powered (minus the kw amp).

There are all kinds of formulas on various forums – mostly for QRPers – that will allow you to guesstimate battery life for a given application based on RF output, duty cycle and a number of other variables.

To find out how much power my K3 uses, I’ll be monitoring its consumption with a Kill-A-Watt during CQWW (and beyond) with the expectation that this will give me the actual result rather than the theoretical.

This neat little gadget will also be monitoring power consumed by the rotator, laptop and a few other items that will be in use during the contest.

Although solar power is expensive, we as hams can more easily justify it since much of our equipment operates on 12V and doesn’t require inverters that “civilians” would need. Solar power is therefore cheaper, simpler and less maintenance-intensive for us.

At least that’s what I’m telling myself for now…



  6 comments for “A Kill-A-Watt for CQWW

  1. November 20, 2012 at 2:58 pm

    I’ll be very interested in seeing your results. When I set up my current HF gear, I decided to use a deep-cycle AGM battery and a 1.25A Battery Tender trickle charger instead of the more traditional (but expensive) high-amperage switching supply. I’m only running an Icom IC-7200 barefoot, and I’m not a serious contester, but this setup has been completely adequate so far.

    • November 20, 2012 at 3:23 pm

      I’m already seeing some eye-opening info:
      The Astron on but with nothing drawing current uses 31 watts.

      • jerry AA1OF
        November 21, 2012 at 5:26 am

        At first I thought wow, because in the QRP world of transmitted power or backpacked batteries, 31 watts to sit and buzz sounds huge. But a 31 watt light bulb left on, at least one of the the old ones, would not seem like that much light and power to be wasting.

        • November 21, 2012 at 5:56 am

          I had the opposite impression at first but I guess for a power supply capable of producing 300 watts, 10% of that to sit and idle isn’t too bad. I wonder how it would compare to a switching supply of the same rating…

  2. November 21, 2012 at 2:53 am

    Hi John, with the increasing energy prizes it is well worth to investigate other power sources as well as a back up for your shack. I saw this on a other blog today, could be interesting http://www.cqdx.ru/ham/new-equipment/low-loss-pwrgate-by-ki0bk/ and not that expensive. By the way I did write something about solar power last year http://pe4bas.blogspot.nl/2011/09/solar-power-in-and-outside-shack.html The interesting thing is I purchased that small cheap solar set last summer with a 30W panel. Just to investigate the possebility of a solar powered shack. Till now I’m still investigating. I already see that I need at least a 100W panel to make a reasonable set up. The main problem is the minimum of sunlight here. The most efficient panels are daylight panels but expensive for hobby use. I’ll write about it later in my blog. And of course I am curious about your experience with solar power for you shack? 73, Bas

    • November 21, 2012 at 5:53 am

      Hi Bas – I did read that blog entry back when you posted it and again last week. I don’t know if I believe the usual sources about how to size a panel to a given transceiver. From what I “know” now (which may change), the panel’s size has more to do with how quickly you want to put power back into a battery and less to do with the power consumption of the equipment being powered.

      In other words, my 70W panel may work with my 100W rig based on how I operate and the fact that the battery will charge all day while I’m at work and not using the rig. We do get quite a bit of sunlight here due to out lattitude and much clear weather.

      I’ll be looking forward to your upcoming posts on the topic as well.

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