Having read the reviews I was very excited to receive this unit! As has been noted, it is well constructed, of good materials, is very lightweight, and comes supplied with high quality Sanyo Eneloop batteries. I was very excited to try it out, and anticipated using it on long distance cycling tours. Unfortunately, my experience varied significantly from other reviews. Perhaps I received a defective unit, or perhaps it had defective batteries that did not achieve/maintain a proper charge. Or perhaps, it is just the Northern climate in which I live. But nonetheless, here was my objective experience, in southern Minnesota, in mid to late May (in terms of intensity of sun). All testing was done outside on clear days, without any trees or other sunlight obstruction. After properly installing the batteries, and placing the device in direct sun, the appropriate charging lights illuminated and the device achieved a full charge in 5 to 7 hours, depending on how close it was to mid-day. I thought this was reasonable for a relatively northern latitude, for a unit of this surface area, and I was excited to proceed with using it.
Unfortunately, my enthusiasm quickly waned. Upon attaching an iPhone 3GS (after fully charging the solar unit and with the light indicating a full charge) and running a golf GPS app, the battery drained from 100% to approximately 40%, over the course of a 4 hour round of golf, on a clear day in mid-May. This is incrementally better than the usual draining from 100% to 20% charge over a typical round without any charging device. So, it did slow the loss of charge, but it was nowhere near able to maintain a full charge. In defense of this unit, the golf gps app does obviously require a lot of power (as indicated by its ability to nearly completely drain an iPhone battery in 4 hours), and the solar charger did delay the power drain somewhat. However, I was hoping that on a clear day, with the unit affixed to my golf bag on a cart, that it would have been able to maintain a much better charge. In fact, the golf bag push cart to which it was attached is angled and I intentionally rolled the cart with the device facing the sun to give the solar device the best opportunity to perform, and the angle of the cart is such that it would facilitate a perpendicular angle of the charging surface relative to the sun.
The next test was the use of the device away from the sun. After fully charging the device in direct sun on a clear day, with the light sequence appropriately indicating a full charge, I brought the device indoors and immediately attached my iPhone 3GS, that was at a mid-charge level. The wireless and bluetooth were turned off, and I put it in locked/standby mode to minimize power usage. I did not want active phone/wireless/bluetooth use to be a confounding variable. After three hours, the iPhone had only gone from 48% charge to 51% charge. While I realize that the solar charger technically "charged" the phone somewhat, it was not doing so at a practical rate, and I terminated the test at this point to use the phone.
As a third test, I inserted two Sony AA 2500mAh batteries that were fully charged by a wall charger, into the solar unit battery chamber, and attached a completely dead iPhone to the unit. It charged the phone from 0% to 51% charge with this set-up. So, clearly, the electrical connections, and USB port worked fine. Unfortunately time constraints and cloudy weather precluded me from testing the device with solar charging with the Sony batteries, to attempt to differentiate betwen bad batteries versus insufficient unit charging capacity as the etiology of the suboptimal performance. I also did not test the supplied Sanyo Eneloop batteries in a home charger, in terms of their ability to accept a charge.
So, there's my experience. You can decide for yourself.
As my experience was an outlier, I encourage others to post their experience. Specifically:
1) Time for solar batteries to achieve full charge
2) Whether they are then capable of charging a device while the unit is away from the sun
3) Ability of the solar device to achieve maintain a charge on your electronic device when in direct sun
If you choose to post, please indicate degree of cloud cover, your location and time of day (as latitude and time of day affects sun angle/intensity) for your experiences.
Who knows? If the overwhelming response is that these units did much better than my experience, maybe I'll reorder one, and try it again, to ensure that it wasn't just a defective unit or defective batteries that I received.