SolarMax solar panel has high-efficiency solar modules are constructed from 36 poly-crystalline, (12V modules) or 72 cells The cells are individually tested and matched for optimum performance before being built into the protective module structure. A TedlarÂ® base is used and ethylene vinyl acetate encapsulate. High transmission tempered glass protects the cells from the front and a high strength polymer sheet at the rear. A reinforced aluminum frame completes the laminate structure which is fully sealed against moisture and protected from environmental and mechanical damage. The most common mistake people make is the mixing of batteries. Car batteries are not good in solar storage and have internal resistance for more information, contact the seller for guideline.A basic charge controller simply performs the necessary function of ensuring that your batteries cannot be damaged by over-charging, effectively cutting off the current from the PV panels (or reducing it to a pulse) when the battery voltage reaches a certain level.