Solar Panel is a durable product and generally require very little maintenance. It can last more than 20 years. Cleaning dirt and dust could be the only maintenance you shall do throughout its lifetime. However, in this case, that we are doing, I believed the angle applied to install the almost 500 units of 260W panels almost zero. That means all the panel laid almost flat that gives almost no gradian for rainwater to flow fast enough to push the dust or dirt out of the panel surface.
I was just wondering why the installer installed in such away. They shall install to have at least 5 - 10-degree gradian to ensure fast water flow to wash away the collected dust or dirt that landed on those panels.
The installation is solid and nicely done except those panels laid flat on the rooftop !
The other problem these panels faced is the chemical mist from the nearby very air condition blower units that installed just beside those panels, except they were lower than the panel height. The Chemical mist that blows from those few units of large blower settled on those panels are now can say cannot be removed. It is hardened and if they are to remove, it will break the panel tempered glass and hence will damage the PV cells. About 20% of the total panel surface is covered by those thick hardened chemical mist from the air condition blowers.
Cleaning the solar panel during day time could be dangerous in case there are cabling leaks. So, we did it at night.