Rechargeable Battery

 

The reusable alternatives to zinc manganese primary batteries are secondary or rechargeable batteries. Initially these were a scaled down version of the lead acid car battery.
This technology actually predates the Leclanché battery by several years being developed by Planté' in 1859. Lead acid is a 2 volt system and therefore not interchangeable with the popular zinc manganese systems. The popular rechargeable alternative to zinc manganese systems was the nickel cadmium system (nicad) developed in 1909 and refined in the 1950s to conform to the standard consumer battery sizes. In overall capacity the nicad battery can be considered equivalent in capacity to a zinc chloride battery or have about the third the capacity of a manganese alkaline battery.
However, although it has a voltage of 1.2 volts, it has a flat discharge curve. Therefore, in applications where there is a high cut-off i.e. the equipment will not work below say 1.1 volts the nicad battery can appear on par with the alkaline cell. Its great benefit is, however, that it can be recharged many hundreds of times. So although it is about three times the price, the disciplined owner can see a substantially saving over both alkaline and zinc batteries. Shortcoming are that it does not achieve its full potential if recharged too soon after only a shallow discharge. This is called the 'memory effect' and the battery acquires the habit of needing charging after only little use. To maximise the benefits of these batteries they should ideally be completely discharged before recharging. Another negative of this battery system is that it contains cadmium, which is a toxic metal and, therefore, should be recycled or discharged in a safe location. Environmental legislation may at some time in the future ban the sale of this product, especially as a new safer high performer is now available - the nickel metal hydride battery. This battery has twice the performance of the nicad, it is lighter, has no memory effect and contains no toxic metals. They are of course more expensive but offer the disciplined consumer the best value for money.