Why are nickel-cadmium batteries superior to lead-acid batteries for standby service?

NiCad batteries use a water-free electrolyte that is not subject to evaporation (even in batteries that are not of the sealed type)

NiCad batteries need fewer cells connected in series for the same battery bank voltage and require less mounting space

NiCad batteries are able to hold their charge for long periods of time without recharging due to less local action (open-circuit self-discharge)

NiCad batteries have electrochemical characteristics that allow specific gravity to be used as a convenient means of determining the state of charge

Why are nickel-cadmium batteries superior to...