Top critical review
3.0 out of 5 starsNOT useful as solar charger for iPhone4
Reviewed in the United States on August 15, 2011
I purchased this unit intending to use it to charge my iPhone4 on a backpacking trip where I was without access to AC or USB power for long periods of time. In my experience the unit is of no value in this configuration. As described by others, the battery charges only to 50% with solar power. This would have been fine if 50% provided any charge to my iPhone4 at all ... but basically it did not. When the unit was charged to 100% from USB then it DID provide a full 100% re-charge to my iPhone4 ... so as a lightweight external battery pack (with enough for one iPhone4 re-charge) it worked perfectly well, hence the 3-star rating. As an iPhone4 charger it would get 0 stars.
The 50% charge level is reached very quickly i.e. within 2 hours or so (at least in New Mexico in August) ... but I suspect that this equates to a too-low voltage to actually charge the iPhone4 at all. The construction on my unit was actually pretty robust and the LED light worked like a charm and the unit was simple and straightforward to use ... but as a solar-only charger for an iPhone4 it was useless in my experience.
I also tried to use the unit to charge a friend's HTC smartphone (when solar charger was showing 50% charge level) and also another friend's (non-smart) phone and neither appeared to receive any additional charge from the unit according to their battery monitors.
For a little more money ($45 I think plus $10 for a specific cable), another trekker with us bought a Solio Rocsta solar charger (from Radio-Shack) and that device WAS able to partially re-charge his smartphone and basically provided just enough juice (with 4-5 hours in the sun each day) to maintain his smartphone between 20-30% charge level for 12 days without AC/USB power.
