What is the value of D1,D2,Q3 and the Voltage / current Rating of Transformer ? can i remove the switch? and the Ammeter?

 

What is the value of D1,D2,Q3 and the Voltage / current Rating of Transformer ? can i remove the switch? and the Ammeter?

The transformer secondary current rating could be anywhere from 1.5A to 6A. I don't suggest going higher than 6A, as you will heat the battery excessively by the rapid charging.

The voltage depends upon the voltage rating of the lead-acid battery you want to charge. This charger is only for lead-acid batteries, NOT gel-cell, Ni-Cad nor NiMH or any other type of rechargeable batteries.

D1, D2 can be any rectifier diodes rated for at least twice the transformer secondary current and voltage. MBR16xx (like MBR1650) would be a good choice.

Q3, the SCR, can be a wide variety of SCRs, as long as it is rated for at least twice the transformer secondary current and voltage.

The switch can be removed. So can the ammeter, but it is a good thing to have.

You have not said where you are, so it is really pointless to suggest specific part numbers. You will have to research what is available in your area.