though that takes away the appeal of getting ‘free’ power
not if you charge it at work
Running out of battery power can clobber your day and leave you incommunicado when you least want to be. There are various secondary power supplies on the market, but few of them can recharge themselves entirely from daylight. The Freeloader Pico claims to be one that can. Solar Freeloader Pico Solar's Freeloader Pico: free …
not if you charge it at work
On eBay I've bought a few unbranded 1900mAh external batteries for charging my iPhone, from Hong Kong for £6.95 each. These work like a dream - quick to charge from the wall (I even daisy chain them) and even quicker to charge the iPhone (each one gives a very-nearly-full charge).
Or - even better - get a phone with a replacable battery and carry a few spares!
As much as I like the idea of renewable energy, the concept of small-scale portable solar power is fundamentally flawed, especially this far away from the equator. A wind-up charger would be far quicker.
but for 17 quid you seem to get what you pay for... crap quality solar panel.
There are other devices of this type around - I've had one for a couple of years. However, I got it for times when I'd be away from mains power for several days at a time, often in sunneir climes. It makes utterly no sense at all to have the ability to charge up from solar power in a UK domestic situation. The environmental benefit of any "free" solar energy is going to be more than outweighed by the resourced that went into installing the panels in the first place. You'll save vastly more energy by not overfilling the kettle a few times.
So if you are going on camping trips in sunny places then it might make sense, but otherwise the solar bit is counter productive. It's also anyhting but free as you pay for it. Charing up a cellphone will typically only take about 0.04 KwH or about 0.4p. It's going to take an awful lot of solar charges before that thing pays back if the "free" power bit was the reason you bought it.
Can someone remind me what happens to the lifespan of a lithium-ion battery if you leave it out in hot sunshine for a few hours? Specially if you apply a black material of some sort to the upper surface?
unless you work for RyanAir
It just doesn't have the solar panel area to be useful.
Though you might get an improvement with a mirror to bring in more light, if you don't cook the thing.
My friend had one of these solar chargers at a music festival we went to last year and it was brilliant - it saved hours of time queuing up to use the limited number of available sockets.
'Free' power could be in respect to the environmental cost.
Given that USB power (generally) comes from an already switched on power supply, exactly how much do you think it costs to charge via USB anyway?
The rule of thumb that most people seem to go by is that a continuous 1W for a year costs about £1 per year, so at a max rate of 500mA, you aren't looking at any more than 50p per year if this is connected 24/7 which it clearly won't be, and assuming that all of that extra power is actually an extra draw on the mains side, which it probably won't be.
Given that most smartphone batteries are in the order of 1000 to 1500mAh, you are barely going get 1/2 charge from this gizmo without allowing for losses.
Power and current are different.
But you may be right.
Batteries get hot. We survive, except when they explode.
I might make the solar panel fold up from the battery and serve as a sunshade for it. On the other hand... why not have an inexpensive collapsible structure to concentrate light onto the solar panel? Like a parabolic mirror?
Inside a window may be not a good place to collect solar energy, e.g. ultraviolet light is blocked(?), what do the instructions say?