Lead-acid battery, Nickel Metal Hydride (Ni-MH) Battery and Lithium-iron Battery have been used as power packs in the electric vehicles. Among those three different technologies and products, Lithium-ion Battery is the best power solution for E-bike applications, because of its high energy density and long cycle life.

Lead-acid Battery as an outdate technology has being used less and less for E-bike applications, due to its heavy weight, large size and non-environmental friendly for battery materials such as lead and sulfuric acid.

Table: Comparison among three battery technologies

item	Lithium	Ni-MH	Lead-acid
Working Voltage	3.7V	1.2V	2.0V
Energy density(Wh/kg)	130-200	60-90	30-40
Cycle life( cycles)	500	400	300
Capacity self discharge rate(% per month)	5%	30%	10%
Memory effect	none	40%	none
Energy efficiency(C discharge/C charge)	99%	70%	75%
Weight comparison for the same capacity	1	2	4
Size comparison for the same capacity	1	1.8	3.5
Reliability	high	low	high