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Off grid and SOTA, solar power


I started my SOTA this summer and I found it very nice to combine both hiking and radio activity. Here in Sweden there are many unvisited peaks in North. Next year, summer, I would like to visit a couple of those. My radio equipment is optimized in terms of weight. But has anyone set up a solar-re-chargable station? My LiPo battery stores 1800mA and it gives several hours of operation with my MTR3B or 5B. But with 7-10 days off grid I need to get some extra fuel into my battery.
Have anyone suggestion on light-weight solar panel and charger/ control unit that works? I would like to have some suggestions or experiances from such operation.

Regards, Jaan


Julian OH8STN is the off-grid guru: http://oh8stn.org/


My DC/DC boost converter

should also work from the 5V output of most USB power-banks, which in turn can be conveniently charged from many modest solar panels.

I got one from Anker but don’t have the model number at hand.

73 de Martin, DK3IT


If you want to have a solar panel with 5v USB, I have done very good experiences with Xtrom AP150. (There is also a stronger variation for example the AP175)
You need a powerbank that has USB input for the solar panel and 12v output for your radio.

vy 73 de Matt HB9FVF


Hi Grovers!

Check out Light Saver Max! 2x 5v 2a USBs and 1 x 12v 5A output. Built in 18000mah (5v) lithium, and 25w rolling solar panel. About the the side of a Glad wrap / cling film box. Will run my 817 all day without an issue - the battery delivers a RF SILENT 12.2v. For QRP ops including my new QRP Digital modes - I simply wouldn’t look any where else.

Interesting for QRO I also have the 12v balance changer for the standard hobbyking lifepo4 that I can use one battery, hook the other up to the lightsaver max to charge and then hot swap back and forward.




That’s good to know! I’m planning to put one of these into a QCX project and now I may have to build in a way to run it from an external USB power-bank.


Lightweight panels: Foldable panels from Powerfilm Solar. Expensive but very good. There might be cheaper alternatives out there nowadays.

Charge controller: You can buy a cheap one that lets you program all the parameters depending on the type of battery you are using. If you want an example, here is how I programmed one for a LiFePo4 battery:

Using this set-up during a SOTA activation, I found some noise on the 40m band. I am planning to test it out with a more expensive and supposedly better charge controller that I bought from Bioenno (once I find it in my mess at home).

Some cables may be too long and too heavy as well and shortening them + adding some anderson power pole connectors may lighten your load and and make your activations more enjoyable.

Good luck!


I suggest a simple DC-DC step down… you can set it to 5v out… arount 1,5 $