Ni - Cd

Ni - Fe

Alkaline magnesium

Lead-acid

high internal resistance

high nominal voltage

low initial cost

all the three stated above

lower e.m.f.

smaller quantity of electrolyte

higher internal resistance

compactness of the cell

float charge

boost charge

trickle charge

freshening charge

less number of plates are to be used

more number of plates are to be used

height of the plates is to be decreased

thickness of the plates is to be increased