My Simple Solar Battery Charger


At a recent ham club meeting we were discussing the fact that as ham radio operators we should be capable of operating off-grid.  By off-grid I mean able to operate our radios, HF/VHF/UHF, without the benefit of commercial power.  Many of us at that meeting decided that we would begin to move toward that goal.  Some already have. 

I had a practical lesson in that very thing not long ago when on a Saturday morning the commercial power went out for about an hour at my QTH.  This is becoming a common occurrence in our area for some reason.  I'm not sure why but it seems like we have more power outages now than we used to have.  At any rate, the fact is that a commercial power failure is always a possibility and is practically a sure thing in the event of a disaster.

But the Saturday morning that this particular outage occurred, I was talking on the local 2 meter repeater to another ham friend.  When I failed to return, he assumed perhaps I had blown a fuse or some such thing.  Well, he wasn't far from wrong.  In fact, the power company had an open breaker at the substation. 

At the time of the outage I was using my Kenwood TS-2000 which operates on a 12 volt power supply I have stuck under the operating table.  But some time back I got me a couple of solar panels off Ebay and a small and inexpensive charge controller from some outfit on the internet.  Seems like I paid around $120 for the 2 panels and the charge controller combined.  I have the solar panels mounted on a homebrew mount on the south side of my house.  I can adjust the angle of the panels to get the most direct sun which increases the output of the panels (see pictures below).  The panels deliver just over an amp of charging current during direct sunlight.  They are connected in parallel with each one capable of a little over half an amp each. 

Inside my basement shack I mounted the small charge controller on the wall (see pictures below).  I ran the output of the charge controller to my 37ah gel cell 12 volt battery.  I leave it hooked up all the time and it's enough to run my TS-2000 for several hours. 

After the power went out I connected the battery to my TS-2000 and I was back in operation.  It's handy that both Kenwood and Icom use the same power plug and connection so the one plug on the battery can run either my TS-2000 or my Icom IC-718.  In fact I use my IC-718 as my
HF PORTAPACK for Field Day etc.  And that 37ah battery is the one I use. 

The moral of this story is that it is neither expensive nor difficult to be ready for an emergency and be able to communicate with the rest of the world.  The advantage of having a solar panel or some other form of alternate energy is that as long as the sun shines you can always recharge your battery.  You can also just keep a trickle charger plugged into commercial power and use that to keep the battery charged up.  The disadvantage of that is if the commercial power is out for several days you would have no way to recharge the battery.

Keep in mind also that as long as you have radios that operate on 12 volts, you can always connect them to the battery in your vehicle and use your home antenna if your vehicle is not equipped for mobile operation.  You can even pull the battery out of the vehicle and take it into the shack to operate from within your shack.  However, you will always want to keep one battery charged at all times so if you only have one vehicle it would not be advised to discharge that one with your radios.  But you could always run a heavy-duty line from your vehicle battery into your shack and start your vehicle on occasion to keep it charged.  Bottom line though, you don't want to be left afoot with a dead battery!  Which brings up another point.  Do you keep your vehicle fuel tank full?  Or do you do like I do and coast into the gas station on the fumes? :>)

By using a small solar panel like mine, the recharge rate is not very fast so I would want to operate on reduced power if possible.  But if I manage my battery properly and use the on-air time wisely I should be able to operate indefinitely as long as I get sunshine every day.  This setup could also be enhanced by a wind turbine to take advantage of the windy days we have around here.  Of course a small gas-powered generator is always a great addition to any emergency setup.

Below are pictures of my solar panel and charge controller.  I would encourage all hams to have some sort of plan for emergency operation because you never know what's going to happen or when it will happen. 

Much of the emergency operations being planned today by government entities rely heavily on cell phones and the internet.  Well, ask the people in New Orleans what the first things to go down were after hurricane Katrina.  If it hadn't been for the ham radio operators in that area there would not have been reliable communications for several days after the wind subsided.

Pictured above are my two solar panels mounted on a homebrew form that can be adjusted for elevation so the panels get the direct rays from the sun at different times of the year.  These are mounted just above the window to my ham shack. The two panels are connected in parallel to provide just over an amp of charge current in direct sunlight. (See text). Above is my small SunGuard charge controller.  It keeps the battery from overcharging in direct sunlight.  It also keeps the battery from discharging during the night through the panels.  The battery clips are connected in such a way that I can connect a voltmeter and ammeter to the controller to monitor the charging and the charging state of the battery.