When using photo-voltaic cells to capture solar power, it might be best to use deep cycle batteries for storage. The sun don’t shine at night, so stored energy is a key to the successful implementation of solar power capture.
Deep cycle batteries are designed less for automobiles and more for complete discharge and recharge. Automobile batteries are lead acid batteries and capable of many years of service when stationary. In a car, they are subjected to rain, snow, bouncing and swaying, and this is less than ideal. Also, a car battery is designed to provide a high current for a short time to start the engine, and not for the continuous discharge that might occur when batteries that store solar power are required to supply power for an extended length of time.
A lead acid battery will have the longest life when complete discharge is avoided. Chemically, the acid and water mixture is less stable at discharge, and most stable when close to fully charged. Overcharge also de-stabilizes the lead acid mixture. Another ill effect of overcharge and discharge is damage to the plates.
Plates in a deep discharge battery are larger and heavier, with greater separation and more resistance to corrosion. A deep discharge battery kept between 50% and 99% charge level can last for decades. Deep cycle batteries will also use a more viscous acid solution that is less prone to separation when a deep discharge occurs.