just for sharing 
Nickel Cadmium. (NiCD) The most popular type of rechargeable batteries used in the industry. Can be damaged by repeated charging without fully discharging. This is called the 'Memory Effect".
Nickel Metal Hydride. (NiMH) These batteries offer capacities up to 30% higher per charge than NiCd batteries of the same physical size. They are less likely to be damaged by the 'Memory Effect'.
Lithium Ion. (LION) The newest rechargeable battery chemistry available. Lithium Ion is not affected by the 'Memory Effect'. It can deliver the same capacity and run time in a smaller, lighter pack. The chemistry is most popular in cellular and laptop products.
Sealed Lead Acid (aka: Gel-Cell) Primarily found in emergency lighting and burglar alarm applications. Designed for steady, constant charging with an infrequent, yet heavy discharge.
original information is from this site
http://www.batterybank.net/digital/batterytypes.html
Nickel Cadmium. (NiCD) The most popular type of rechargeable batteries used in the industry. Can be damaged by repeated charging without fully discharging. This is called the 'Memory Effect".
Nickel Metal Hydride. (NiMH) These batteries offer capacities up to 30% higher per charge than NiCd batteries of the same physical size. They are less likely to be damaged by the 'Memory Effect'.
Lithium Ion. (LION) The newest rechargeable battery chemistry available. Lithium Ion is not affected by the 'Memory Effect'. It can deliver the same capacity and run time in a smaller, lighter pack. The chemistry is most popular in cellular and laptop products.
Sealed Lead Acid (aka: Gel-Cell) Primarily found in emergency lighting and burglar alarm applications. Designed for steady, constant charging with an infrequent, yet heavy discharge.
original information is from this site
http://www.batterybank.net/digital/batterytypes.html
