From http://www.axionpower.com/Technology http://www.axionpower.com/Technology: "Our test protocol requires a complete charge-discharge cycle every 7 hours to

From http://www.axionpower.com/Technology http://www.axionpower.com/Technology: "Our test protocol requires a complete charge-discharge cycle every 7 hours to a 100% depth of discharge. During testing, our laboratory prototypes have withstood more than 2,500 cycles before failure. In comparison, most lead-acid batteries designed for deep discharge applications can only survive 400 to 600 cycles under these operating conditions." The interesting part about their batteries isn't the lifespan, it's the lifespan under 100% depth of discharge. You can easily get around 2k cycles out of a flooded cell lead-acid battery, but you can only go down to 60% discharge and you must carefully monitor the battery chemistry to get prolonged lifespan. Along with it's high current capacity, this would make it an interesting battery for renewable energy storage more than anything else. It's too bad they don't have a solid datasheet for their product yet. I'd like to see their figures for internal resistance, self discharge and performance over typical operating temperature ranges. Until we get to see this data, it's hard to say if this will be a profitable product.