'Splain me 'bout solar chargers...

[Buzz]

What possible good are they for real world phone/tablet use? Seems like they charge at around 200mAh in bright sunlight, so if you're lucky enough to get the equivalent of 10 hours of bright sun per day, it'll take 10 days of pointing the thing at the sun to fill up a 20,000mAh unit under optimal conditions, w/ no loss due to any operational gotchas. Reality would be more like two weeks. It just doesn't seem to me that they're efficient enough to justify the hassle of schlepping them around. Like Eric Burdon said in the 70's, "What are they good for?"
Thanks.
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