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Repairing a battery charger.

Gonzo

New Member
Hello,
I have a few old school 12v automotive battery chargers using the selenium rectifiers. They are rated at 10a yet the aged rectifiers will only produce about 2-3 amps. Being that they are hard to obtain I installed a bridge rectifier which now outputs the full rated amperage.
Being aware of the fact selenium rectifiers will reduce current as the battery becomes fully charged I wish to retain them.
These chargers are set up with 2 taps coming from the transformer feeding each of the selenium rectifiers and then out via the negative battery clip.
My question is can I simply add a switch on the selenium and bridge rectifiers output thus allowing the bridge to provide a high amp setting for faster charging, then switch to the selenium for a slower limiting charge?
My thoughts are making a "Y" in the transformer to rectifier wires and feeding the selenium off one set of "Y" and the bridge off the other then running their output through the switch to the negative battery clamp wire.
Both rectifiers will be fed from the transformer but depending on the switch position, only the bridge or selenium would be active.
 
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