New Outdoor Radio Clock Using Electric Double Layer Condenser for Electric Storage

CITIZEN T.I.C. CO., LTD. (the consolidated subsidiary company of Citizen Holdings Co., Ltd.) started the sale of a new solar cell-driven outdoor radio clock (on June 6, 2010). The outdoor radio clock uses the electric double layer condenser for electricity storage. The Ni-Cd battery has been used for the same purpose. The primary power source of the clock is a solar cell.
Advantageous features:
1) The battery replacement period is significantly long, about 15 years, while that of the Ni-Cd battery is about 5 years (since the battery performance is less deteriorated through the charging/discharging operation.)
2) Environment friendly and safe (since toxic heavy metals (e.g., cadmium or lead) are not used.)
3) Even on cloudy and rainy days, the capacitor battery can secure the electric power consumed during the day through the charging operation, with good charging efficiency.
4) No time correction work, no electric wiring work, and no electric fee

Price: 320,250 yen to 1,176,000 yen (before taxes)
Electric storage: electric double layer condenser (1300 F) x 2
The product details are here.

Note:
The capacitor technology has reached such a level as to allow the capacitor to be used in place of the battery. In the Citizen’s outdoor clock, the Ni-Cd battery is replaced with the capacitor. It seems that the defects of the clock, which result from use of the Ni-Cd battery, have been removed. The capacitor functions to store electric energy while receiving weak current from the solar cell when it is cloudy and rainy. This feature of the capacitor is also important. The capacitor caught my eyes since I have just introduced the new capacitor using single-layer carbon nanotube electrodes, developed by AIST, and the capacitor still remains in my brain.