fake solar charger / battery pack for iphone 3G?

the other day when i was in Shenzhen i decided to look for an external battery pack for my iPhone 3G.   On days where I'm out all day listening to music, watching video and surfing online (like days when I go biking for example),  the iPhone's battery is just not enough. 

I think if you do continuous surfing in 3G mode, you can probably completely suck the battery dry in an hour or two.  I made the observation before that I don't think its possible for me to use up all 500mb of my monthly data plan,  because even if you downloaded stuff every day for a month continuously til your batter ran out, you'd never get 500mb. :-P

Anyway, the shop i stopped by had a small plug in battery recharger (its basically an external battery).  I talked the guy down from 90 RMB to 50 RMB (~US$7).  But then when I tried it, my iPhone gave a warning message saying the device couldn't be recognized, etc etc.

So he convinced me to pay an extra 100RMB for a fancier battery pack he also had...  but this one had a...  "太陽能晶片"... which I quickly realized meant 'solar cell'...  

Basically the battery pack was the same as the other one, but it has a small solar cell on the back side.  He showed me how when you put it up to a light there's a small LED lights up ("that means its charging!") ... but I'm a bit skeptical of the solar thing...

frankly the surface area of the solar cell is quite limited.  I'm not sure if its really big enough to charge this thing at any reasonable rate.   But worse case senario it at least works as an external battery... :-P

I ended up buying it for $150RMB (~US$20)... partly because I was curious if this thing would really work and partially because I actually really needed to recharge my phone!

Turns out you can buy it in bulk from the factory for like $13 each (min 50 pcs)

I have a sneaking suspicion that the solar cell is actually fake and there's just a photosensor in there somewhere that turns on the 'charging' light if its under bright light... but doesn't actually charge anything.

I haven't had time to do any emprical testing... partially because I spend most of my time sitting in rooms with poor, artificial lighting.  :-P

I think I'll try to run down the battery on my phone til its almost zero, then plug this charger in and drain its battery down til its zero, then flip the thing over and see if the solar cell actually produces enough current to keep the iphone running.... (or better yet, actually charge the batteries).   I'll keep everyone posted. :-P

this is actually false advertising, the solar cell is on the back side, so you can't have the phone charge on the table top unless its face down. :-P

UPDATE (10/07/09):For those who are finding this through google and considering getting one - don't waste your money on the solar...  as near as I can tell, its complete BS.  After wearing down the charge to almost empty, I left it out in the sun all day and tried charging the phone and it wasn't charged up at all.   I think its just a photo sensor. :-PAlso I don't recommend this style of battery because it is curved to follow the contour of the bottom of the phone.  this means you must remove any case you have on the phone,  also its easy to come slightly off and disconnect the charging (so you end up having to hold it in to charge sometimes).   Lastly the one i have seems to have a small battery (maybe only 500 mAh?),  where as the newer ones you can get now have 1500-2000 mAh batteries... which can basically charge your phone all the way from empty w/o running out.