Secondary batteries are the rechargeable batteries. Theyhave the advantage of being more cost-efficient over the long term,although individual batteries are more expensive. Generally,secondary batteries have a lower capacity and initial voltage, aflat discharge curve, higher self discharge rates and varyingrecharge life ratings. Secondary batteries usually have more active(less stable) chemistries which need special handling, containmentand disposal. Ni-Cd and small-size lead acid batteries requirespecial disposal and should not be simply thrownaway.
Best solution for high drain applications
For high utilisation applications the cost of the chargeris soon paid back.
Cost of charger. For low cost applications such as toysthe charger could cost much more than the product itsupports.
Safety issues with mains power.
Lower energy density than primary cells unless exoticchemistries used.
Lack of standards
Many custom pack designs and limited interchangeability.(Disadvantage for the user but creates a captive aftermarket forthe manufacturer)
Typical Battery Chemistries
Nickel Cadmium (NiCad)
Nickel Iron (NiFe)
Nickel Metal Hydride (NiMH)
See also Primary Batteries