Keep solar panel clean. If solar product does not light up after it has been used for around 8-12 months, replace the rechargeable batteries as they may be weak or worn out. Recommended battery 1pc AA 1.2V 600mAh, Ni-MH or equivalent must be used for best result Open the battery compartment cover and replace 1pc AA (rechargeable only). Be sure to observe the correct polarity.