Battery Tutorials from BatteryStuff.com for Lead/Acid batteries describing in common language how these batteries work, testing, charging, and life/performance.   Topics include charging, Gel vs AGM, NiCd, NiMH, and other general information. Deep Cycle Battery FAQ from Northern Arizona Wind & Sun including Types of Batteries, Wet vs Gel vs AGM, Amp Hours, Charging, and lifespan. Storage Battery Manual principles of storage battery construction and design, with the application of storage of batteries to the naval service.