Last year, I purchased a hands-free Bluetooth car kit as a Christmas gift for a family member who, as a sales rep, spends significant time talking in her car. Worried for her safety as she drives with one hand on the wheel and the other around a cell phone, I initially felt a sense of pride as she unwrapped a gift that demonstrated concern for her well-being.
Sometimes, however, a buzz can be short-lived. After a quick explanation of what the gift was, I could see a bit of uneasiness creep in as she unraveled the 3-foot long charger cord and asked if it would be necessary to keep this plugged into the single charger in the front seat of the car. She soon came to the realization that "hands-free" was not "cords-free."
I assured her that, after an initial charge, she would only need to occasionally plug in the hands-free car kit, freeing up the outlet for her cell phone. After juicing things up, we quickly had the device paired with her cell phone and she was off and using the hands-free device. It wasn't long before a week's lapse in charging left the car kit out of gas and no longer paired to her Bluetooth-enabled phone. The process of hanging the charging cord from the roof of her car to the outlet, combined with the re-pairing of the device, soon sent the hands-free car kit to the electronic junk bin, where other well-meaning gifts had already met a similar fate.
Looking back over the years at the Bluetooth headsets I've purchased for my own use, I soon realized that they too had gone the way of the hands-free car kit for the same reason--another cord to carry and another device to charge. Ugh.
So, it was with great enthusiasm that I ordered the Iqua SUN for a Portelligent teardown, to see how advances in Bluetooth and integrated solar power could enable a Bluetooth device that may never need to be plugged in. According to the company's Web site and product packaging, Iqua claims the SUN is the world's first solar powered Bluetooth headset with the potential for infinite standby time if exposed to sunlight on a regular basis. If a cord were truly no longer needed, perhaps this could be a Bluetooth-enabled gift able to escape the fate of hands-free car kits and other gadgets whose shine faded with time.
At a price of $70, the Iqua SUN costs $20 to $30 more than comparable non-solar powered Bluetooth headsets. Weighing 14 grams and occupying a surface area of 11 cm sq., the SUN is both heavier and larger than today's smallest Bluetooth headsets, such as a recently analyzed Samsung WEP500, which weighed in at less than 10 g and had a surface area approaching 6 cm sq. While non-solar-powered Bluetooth headset manufacturers are constantly striving for smaller form factors, limited only by the size of the small lithium-ion battery housed in the headset, shrinking the size of the SUN may not be in Iqua's best interests due to the surface area required for the 4 cm sq. amorphous silicon solar cell.
After disconnecting and removing the solar cell, measurements indicated a maximum open circuit voltage of 4.1 V in direct sunlight. Maximum short-circuit current in direct sunlight was approximately 5 mA. These numbers indicate a solar cell with a peak output of 10 mW to 15 mW when normalized according to conventional wisdom for combining open-circuit/short-circuit measured outputs. Fluorescent office lighting with indirect sunlight generated a less hardy figure of under 1 mW from the solar cell.