Ni-Cd batteries are rechargeable batteries that can be deeply discharged and have a high cycle life expectancy. Ni-Cd batteries are used when large capacities and high discharge rates are required. Apart from the usually higher cost of Ni-Cd batteries, the biggest disadvantage of Ni-Cd NiMh batteries is their chemical components.

NiCD batteries were invented in the 19th century when environmental concerns did not exist. Cadmium is a highly toxic heavy metal and can cause substantial pollution when landfilled or incinerated. Ni-Cd batteries require a charger with a higher voltage. While these chargers exist, they are more costly again. A fully charged 12V battery bank can also go as high as 17V, which could cause inverters to shut down or worse.

In addition, NiCd batteries are notorious for losing their capacity over time and it's not just model plane enthusiasts who suffer. With their high current capability, NiCd batteries are used in everything from computers to power tools. The charging efficiency of Ni-Cd rechargeable batteries is generally rather low which means of the electricity you put in, only 70-75% can be retrieved. In comparison, lead acid batteries convert about 85% and sealed lead acid batteries are even better.