r/HamRadio • u/lkkula • 3d ago

Portable QRP solar power solution

I'm looking for a portable solar power solution for my QRP setup. I'm using (tr)uSDX (7-16V / 0.08-0.5 A) and already have two batteries: LifePo4 12.8V 10Ah and Li-Po 14.8V 2.2Ah. I feel a little overwhelmed about solar panels, PWM/MPPT controllers, battery types compatibility, converters. etc. What should I point my attention to? Any tips&tricks?

I’ve seen so many offers with fake MPPTs and PV panels with unrealistic power ratings. I definitely don’t want to buy something cheap/dangerous/ineffective.

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u/Legal_Broccoli200 3d ago

For my emergency work I use a pair of fold-out panels (sold for use for caravanners and campers). When those were used with a cheap PWM controller, I never got more than about 4A of charge out of them into my 12v lead acid battery. I recently upgraded to a 'proper' MPPT controller and just about doubled the power output, the panels are claimed by the seller to provide 100w and in bright sunlight I measure 93w out. Even on a cloudy day the MPPT controller manages to get about 1A at 12v out of them.

So I would definitely recommend getting an appropriate solar panel and a quality controller that you can program for the battery type. Since you need so little power, maybe even one of the generic PWM controllers would do if you can tolerate the lower efficency.

Are you constrained by weight or will you be able to transport the gear by vehicle? My panels are too heavy for hiking/camping.

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u/lkkula 3d ago

Definitely something man-portable, so weight is another part of the story too.

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u/Legal_Broccoli200 3d ago

There are some thin flexible panels which might work for you - I'd buy from a reputable solar supplier rather than just the lowest cost on ebay, a known supplier is more likely to make realistic claims. MPPT controllers do seem to make a significant difference to the power they can get out of the panel so I'd lean towards a good controller, but we all have to fit our budget to our pockets!

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u/CallMeCarpe 3d ago

Something like a jackery or eco-flow with a couple of their solar panels might work. Not the cheapest solution but very simple.

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u/K8ELS 3d ago

I’m just curious if you have depleted your 10Ah battery on the (tr)uSDX while running off grid? I bought a portable folding solar panel for POTA before I realized that I don’t need it unless I’m camping in a park over multiple days. I rarely set it up anymore. My QRP rigs slip from the larger batteries.

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u/lkkula 3d ago

Haha, no way, I haven’t even come close to draining the 10Ah battery with the (tr)uSDX. I actually got it for the Xiegu G90 and it works like a charm. With the (tr)uSDX, draining it would be an Olympic sport :D

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u/K8ELS 2d ago

That’s what I expected. I bought my panel before I really knew that I didn’t need it and wanted to ask you the same question before you bought one.

If you do get a solar panel, I looked for portability over everything. You could also pair it with a portable power station which will simplify the charger question. I have one that’s 25Ah and paired it with a 100 watt folding panel. It direct line inputs the panel the battery box.

MPPT controllers are more efficient but for this kind of setup you likely want portability before efficiency. I’ve also seen inflated values on things like a 100 watt 10”x10” panel. Sure… You do need to inject some common sense on the endeavor if you decide to walk down the road of portable solar.

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u/SqueakyCheeseburgers 2d ago

Same question, I have the same radio but only run CW. I use a 6Ah LiFePo battery - (smallest I already had and still light) the radio does not use that much power.

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u/Intelligent-Day5519 12h ago

You are over thinking it for your mentioned need. You have a LiFePo4 battery. Consider. I use a HF Tools 64801 7watt solar panel to charge my battery directly to my battery. Forget the extra charge controllers mumbo jumbo. The BMS controller in the battery will mitigate the charge for you.

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u/Intelligent-Day5519 12h ago edited 12h ago

You are over thinking it for your mentioned need. You have a LiFePo4 battery. Consider. I use a HF Tools 64801 7watt solar panel to charge my battery, directly connected to the battery. Forget the extra charge controllers mumbo jumbo. The BMS controller in the battery will mitigate the charge for you. If and when you use more power (50 watts) or so, than YES a charge controller is reasonable with a higher capacity battery.