Versatile NiCad trickle charger
This circuit can be the basis for a multi channel NiCad charger unit , The charge rate being controlled by the value of R4 ,
1 to 14 cells can be charged with the 18 Volts input suggested , Cells should be trickle charged at 10% of there rated discharge current ie a 3000m/a cell at 10% = 300m/a ,
I built the prototype on a piece of Veroboard,with a large heat sink using TIP31a transistors , Ending up with seven channels rated from 25m/a to 300m/a .To cater for my electric flight NiCad packs ,
The Prototype Cost just a couple of pounds to build , Most of the components including the LEDs and DC power supply were recycled from an old Amstrad computer modem ,Outputs are on flying leads , A "couple of pounds" were spent on the TIP31A transistors and mounting kits . The DC power supply is rated at 1.5 Amps so i can trickle charge all my present electric flight packs overnight , Thus ensuring peak performance on the field . Regards Ken..