Arizona Solar Center Blog

This PV array was installed under a tree and as a result the branches of the tree were casting shadows on the PV modules.

During normal operation, water is lost from a flooded lead-acid battery as a result of evaporation and electrolysis into hydrogen and oxygen, which escape into the atmosphere. One Faraday of overcharge will result in a loss of about 18 g of water per cell. Evaporation is a relatively small part of the loss except in very hot, dry climates. With a fully charged battery, electrolysis consumes water at a rate of 0.336 cm^3 per cell per ampere-hour of overcharge. A 5000-Ah battery overcharged 10% can thus lose 16.8 cm^3, or about 0.3%, of its water each cycle. It is important that the electrolyte be maintained at the proper level in the battery. The electrolyte not only serves as the ionic conductor, but also is a major factor in the transfer of heat from the plates. If the electrolyte is below the plate level, then an area of the plate is not electrochemically active; this causes a concentration of heat in other parts of the battery and “Sulfation” of the dry portion of the plates which may not be reversible. Periodic checking of water consumption can also serve as a rough check on charging efficiency and may warn when adjustment of the charger is required.

Following is a collection of common mistakes made when installing solar electric systems.

Solar utilization has a long history, beginning with some of the earliest structures in which humans lived. The early inhabitants of what we now call Arizona probably did not think of their homes as passively heated and cooled. They built them in response to the climate, to social and cultural standards and to their need for adequate shelter. They did not have available to them abundant energy resources or mechanical devices for moderating the indoor climate of their homes. So they used what was available - the sun, wind, caves, fire and available materials such as branches and sticks, and mud and stone. If necessary, they built several dwellings, including one for summer and one for winter.