| 摘要 |
A free standing outdoor telephone booth is provided with a photo voltaic (PV) array, one or more rechargeable storage batteries and electrical control circuit which includes a temperature compensated control for limiting the supply of electrical energy from the PV array to the rechargeable battery to avoid over charging the battery, an ambient light (solar insolation) sensing circuit for controlling the electrical lamp load, to turn the lamp ON during dark ambient and OFF during light ambient conditions. In addition, the total discharge limit of the storage battery is controlled to a safe operating limit and a means is disclosed to power a fluorescent lamp at energy conserving intensities with energy derived from the rechargeable storage battery. The lamp control circuitry is preferably constituted by a high frequency power inverter with regulated output power to energize a low wattage fluorescent lamp and to dim the fluorescent lamp when the telephone is not in use. The PV array may be mounted in the roof of the booth, or may be mounted remotely or on adjacent structure on poles disguised as phone signs. Multiple commercially available PV arrays and storage batteries may be connected electrically in parallel to provide higher reliability and/or greater electrical energy capacity.
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