[ARC5] Paralleling Rectifier Diodes (releazer at earthlink.net)

[SCOTT JOHNSON]

You'll see the voltage go up when you put the battery on charge, as it acts like a capacitor, and you will see closer to the peak value.  This is characteristic of most simple transformer-rectifier chargers.
Scott Johnson W7SVJ/AFA6SJSunburst Engineering5111 E. Sharon Dr.Scottsdale, AZ 85254(480) 550-2358scottjohnson1 at cox.net 

    On Sunday, May 5, 2024 at 12:19:52 PM MST, Charles via ARC5 <arc5 at mailman.qth.net> wrote:  
 
   
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: releazer at earthlink.net
To: arc5 at mailman.qth.net
Subject: [ARC5] Paralleling Rectifier Diodes
Message-ID: <ec564be5-ce36-81ca-8e5b-c4a07bf126f5 at earthlink.net>
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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 
 
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