Keep in mind that with no filter capacitance, the average DC value of the output, which your meter will read, with a full-wave rectifier will be 0.9x the peak value, less one diode drop (~0.7V at light load, more drop while passing 10 amps).

At no load the peak voltage will actually be (22/0.9) + 0.7 = 25.1. That still sounds low though since I'd expect 28V or more while charging.

Does this charger have selenium or silicon rectifiers?

What does your meter read when putting the charger on its 12V range?

-Charles

WB3JOK :)

Message: 2
Date: Sun, 05 May 2024 18:14:47 +0000
From: [email protected]
To: [email protected]
Subject: [ARC5] Paralleling Rectifier Diodes
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8

Yesterday I found a 12/24V 10 amp battery charger someone tossed out.  It seems to work fine on the 12V setting but the voltage output is only 22V on the 24V setting even with no load.  Oddly enough it uses a center tapped transformer and two rectifier diodes to produce a full wave output, although without any filter caps.  It seems that one of the rectifier diodes has an excessive voltage drop on the 24V setting.  How would you parallel rectifier diodes, in case I do not have any suitable diodes to replace the defective one?

Thanks

Wayne
WB5WSV