High brightness LEDs and special optics allow street lamps to be spaced up to 50 meters apart -- much wider than is possible with other solutions. By charging these street lamps efficiently during daylight hours using solar energy, the capacity of the conventional electricity grid can be supplemented, saving money and reducing CO2 emissions. This solution dubbed Solar Gen2 and developed by NXP Semiconductors in collaboration with Philips Lighting has resulted in the most cost-effective solution per km of road lighting and provides a serious alternative to grid-connected AC systems.
NXP's MPT61x range of intelligent charge controllers for maximum power point tracking (MPPT) make it possible to transfer the maximum amount of power from the solar panels to the batteries, achieving up to 98% power conversion efficiency with solar photovoltaic (PV) cells. The controller that includes an ARM7TDMI-S MCU core running at 70 MHz features intelligent algorithms for battery charging and discharging to maximize battery life and it is also capable of dimming light levels as needed based on self-learning and a history log.