... panel, amorphous silicone,mono-crystalline silicone,poly-crystaline sillicone.B, Mono-crystalline and poly-crystalline solar panel's Characteristic ... electricity leakage & water seepage when the battery is buried underground.B, Life span ≥5year , Gel battery: ≥8 yearsController, ... LED constant current driver which consumer 15-20 of system power.B. intelligent digital controller can save >80% power ...