The original rechargeable NiCad battery pack could also be used in the Pro model. The MIT team converted a 1968 Chevrolet Corvair powered by NiCad batteries. Also, early NiCad batteries tended to have a short lifespan. Both wall transformers and NiCad battery packs were originally offered. NiCad batteries were in use in a few canister lights by 2000. NiCad batteries of this period suffered from the Memory effect. The battery was a NiCad that could charge in only 15 minutes. Also due to partial charge cycles due to the 'memory effect' of the Nicad cells. A lithium version was later introduced as a lightweight replacement for the 24V 4Ah NICAD. Specialists can rebuild the unserviceable Clansman NICAD battery. Rechargeable batteries, such as NiMH and Nicad, are economical options for lights with heavy usage. NICAD is that failure of these diodes makes batteries unserviceable. Nickel Cadmium (NICAD) type later upgraded to 4 ampere hour (or Ah).