Dear Ahmad;

Solar cells have no problem, but problems with batteries and how long they store energy.

لا توجد مشكلة فى الخلايا الشمسية ، ولكن مع البطاريات والوقت الذي تخزن فيه الطاقة

Dear Usama Badawy yes you are right also i think it's necessary to clean it every week because we have a bad weather and most keep it cools in hot days.

That true Dear Mohamed Azab.