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I'm in a country with an unreliable power supply but plenty of sun. I currently keep my work computer and phone going with a portable fold-up PowerAdd 60 watt solar panel, which has built-in voltage control fixed to cap the output at 18 volts max (as well as optional USB output). I use it to recharge one of two lithium polymer battery packs designed to recharge laptops. These can take input from 15V to 20V (it says 15V-19V but the manufacturer's supplied charger outputs at 20V), so it works very well and is elegantly simple: panel, cable, battery, done.

I'm looking to expand my setup with a third battery and second solar panel, to have a spare fully charged battery that can be charged in a day and used to power other appliances such as a 12V fan and a 19V LED TV, which both can be powered from these LiPo batteries when there's no mains electricity. The 60 watt panel is okay, but given placement limitations in my compound costing maybe 20-30% of ideal daily output, it can't quite fully charge one of these batteries in a day, struggles to exceed 2.5 amp output at 18V for more than an hour or two even on a good day, and can't get a high enough voltage to charge at all before around 9:30am and after around 6:00pm. I'm going to need a bigger panel.

My problem is, PowerAdd only go up to 60W, and all the panels over 60W I can find either have no voltage control, or output at 12 volts, which is too low for my needs (or doubled-up to 24V, which is too high).

Is there a durable, reliable solar panel (preferably portable, but not necessarily), with output 100 watt or greater, that prevents output voltage exceeding 20 volts, but allows output at 15 volts or more?

Something with manually adjustable voltage would be amazing (like my batteries which can be switched between 12, 15 and 18 volts), and optional USB output like my current panel would also be nice, but these aren't essential. 5mm/2.5mm DC barrel plug connection would be nice for easy compatibility with my existing setup but adaptors are easy to find so that's a minor consideration.

My main criteria is, I'd like something simple without needing bulky inverters or a bulky heavy duty voltage regulator. Portability is a big bonus - while I don't need to take it camping or anything, I'll need to get between locations in West Africa and Europe and possibly elsewhere, so ideally I'd like something that could fit as luggage on a plane, in a car, etc.

At a push, a panel with output at 15V or 16V would be an acceptable compromise, since these batteries could still charge, but 12V is definitely too low.


Update: something like this 120 watt panel from EBAT would be ideal, but I can't find any reviews vouching for its quality, durability, real-life outputs, etc and it also doesn't specify whether it's designed to avoid taking charge from a device when the light level is low.

There are also some promising looking panels from AliExpress, like this 120 watt OEM panel which claims to output at up to 18V (or 12V with a charge controller), again, no 3rd party reviews I can find anywhere.

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This looks promising: RENOGY® Foldable Solar Suitcase Kit 100W Mono.

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  • 100 watt output
  • Maximum Power Voltage (Vmp): 18.0V.
  • For an extra $20 there's an optional charge controller that can limit this to 12V, and they say in answers to questions that it's fine to charge things other than 12v lead acid batteries without using the charge controller, straight from the panel.
  • Heaps of detailed positive reviews! A couple mention connection problems, but add that they had no problem fixing these
  • Portable, includes its own stand
  • At $240 USD, it's cheaper than my 60w panel was!

More details at Renogy's site. At 12kg and folding to the size of a large suitcase (Renogy's site has an illustration) it's portable enough for my needs (occasional house-to-house or air travel but not backpacking or camping).

Regarding waterproofing, they say:

The solar panels are fully waterproof (IP66 class), the controller is not.

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