Solar Auto-Fill is a totally automatic, maintenance-free swimming pool water level control, designed to be installed in any pool, new or old. The rechargeable battery is charged by the sun, so there are no batteries to replace. This sophisticated system incorporates highly reliable, extra long-range wireless electronics. The level sensor/transmitter is attached to the tile at the water line with very high bond double-sided tape. The receiver is installed near the filling valve and powered by a low voltage power adapter.