Description.
Notes.
Here is a simple charger circuit for charging
SMF(sealed maintenance free ) batteries.The charger circuit being
curernt and voltage regulated,can be safely used to charge SMF batteries
of 1.2 AH rating.This circuit was actually designed in response to a
request from a reader.With slight modifications you can use it for
charging any sort of SMF batteries.
The first part of the circuit is the power supply
made of transformer T1 and diodes D1&D2.The capacitor C1 filters the
rectifier output .The next part is the section comprising of IC1 and Q1
which provides the necessary volatge and current regulation.The diode
D3 prevents ther reverse flow of charge from the battery .
Circuit diagram with parts list.
Notes.
- Assemble the circuit on a good quality PCB or common board.
- An ammeter can be conncted in series with the battery to monitor the charging current.
- Do not short circuit the charging terminals of the circuit.The circuit doesnot have short circuit protection.
- R4 is the component that determines the charging current.Here it is set to be 120 mA. R4= (0.6 V/Charging current).By selecting the proper value of R4 according to equation, you can charge batteries that require different charging currents.