What is the difference in discharge/recharge cycle life between Lead-acid (PbA) cells and Lithium-Ir

Lead-Acid (PbA) deep-cycle battery packs can usually be discharged and recharged for 300-700 cycles, depending on the quality of manufacture.  However, discharge rates are also subject to temperature and weather conditions throughout the life of the pack. This means potential replacement for deep-cycle battery packs is about every one to two years. LiFeBATT guarantees its cells for 1,500 deep discharge/charge cycles before a 15% degradation of overall capacity may occur.   Past the 2,000 cycle threshold, the cells still don't need replacement, but the user will notice a 15% reduction in battery capacity after a full charge.  For an electric vehicle, a driver might see a 15% reduction in distance traveled as the battery pack ages beyond 2,000 cycles. 

The definition of 2,000 deep discharge cycles for LiFePO4 chemistry is 72% - 98% depletion before recharge. Shallow discharge/recharge cycles will prolong battery pack life, extending it beyond 5,000 cycles with little loss in overall capacity, up to 10,000 cycles before degradation of overall battery capacity starts exceeding 15%.  Shallow cycles are defined as less than 72% discharge and can be maintained by always allowing more than 28% of the battery pack capacity to remain undischarged when reconnecting the battery pack charger.  At 2,000 deep discharge/charge cycles, averaging 1 cycle per day would allow for 5.5 years of use before a noticeable loss of capacity. 10,000 shallow discharge/charge cycles would last around 13+ years.