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Battery charger only putting out 9 volts instead of 12?

Black_Blade

Feb 16, 2014
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Feb 16, 2014
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Our Solar Octane battery charger had its pcb board come loose inside the case and it shorted against something when it fell. I ordered a replacement board for it but it seems there is something else wrong with it for it only puts out 9 volts on two of the three switch postions (2 A 12 volt, 10A 12 volt). The car start position still puts out 12 volts. I don't have a battery at the moment to place a load on the charger for testing purposes, just putting my meter on the output clamps. Would anybody have an idea of what I could check next? Would the rectifier board be toast? Can I test it with ohmmeter before just ordering a replacement?

Was gonna upload the schematic but the single page pdf is 2.89 MB and too large for the file limits. Its a OS6110 wheeled charger. Wiring diagram I downloaded was from this site:http://www.tesstools.net/OS6110_1330_Parts_List_s/2036.htm

Also wondering if there is a way to test the rectifier and transformer on this unit, to see if its the culprit?
 
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mursal

Dec 13, 2013
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Dec 13, 2013
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If you want to check the junction diodes in the rectifier.
Disconnect all the wires, especially the transformer

With the multimeter in diode test, you should get an open circuit, when the meter is connected across the diode in one direction and a forward voltage (0.4 - 0.7V) with the meter in the other direction.

You may have an open winding in the transformer
 
Last edited:

Black_Blade

Feb 16, 2014
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Feb 16, 2014
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If you want to check the junction diodes in the rectifier.
Disconnect all the wires, especially the transformer

With the multimeter in diode test, you should get an open circuit, when the meter is connected across the diode in one direction and a forward voltage (0.4 - 0.7V) with the meter in the other direction.

You may have an open winding in the transformer
Test for open windings on transformer with ohmmeter across primary and secondary lines I guess?
 

Black_Blade

Feb 16, 2014
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I pulled out the rectifier board and tested all 8 diodes and they all are open one direction and drop .5 v the other way, so guess thats good to go. As far as testing the transformer, not sure how to go about that for it has all kinds of wires coming off of it aside from the two that connect to the rectifier.
 

mursal

Dec 13, 2013
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Yes the diode pack seems OK. What voltage have you across the secondary going to the rectifier? Don't forget you have mains voltage on the primary side, so be careful.
 

Black_Blade

Feb 16, 2014
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Will check the voltage across the secondary, but just wondering what, if any role does the switch play in it all. Would it be a cause of getting 9 instead of 12 volts in two positions? Its all one enclosed unit, so guess its pretty tough to tell if anything is going wrong inside it?
 

davenn

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Sep 5, 2009
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not having seen you unit .... some pix would help

the switch probably switches between some large resistors to do current limiting
that a good guess till we see your unit

Dave
 

Black_Blade

Feb 16, 2014
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Measured the output to the rectifier leads at various switch positions, I get:
21, 24,27 and 30 volts. I've attached some pics of the machine.
 

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duke37

Jan 9, 2011
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Your charger may be working correctly.
Without power, you can check the diodes by measuring the voltage drop across the output using the resistance range. If there are four diodes, the drop should be about 2V.

An AC source has a varying voltage. The voltage quoted is normally the RMS voltage which will do the same work on a resistance as the equivalent DC voltage.
The peak AC voltage is 1.414 * Vrms
The mean AC voltage is 0.9 * Vrms
This changes little when rectified to DC except for diode voltage drop.

So an 11V source will rectify to 10V.
It will have a mean voltage of 9V which is what you measure.
It will have a peak of 14V which is enough to slightly charge the battery.

To check the operation, you will need a battery but some indication could be obtained by putting a capacitor (1000µF or so) across the output to hold the voltage up between charging pulses.
 

Black_Blade

Feb 16, 2014
7
Joined
Feb 16, 2014
Messages
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Your charger may be working correctly.
Without power, you can check the diodes by measuring the voltage drop across the output using the resistance range. If there are four diodes, the drop should be about 2V.

An AC source has a varying voltage. The voltage quoted is normally the RMS voltage which will do the same work on a resistance as the equivalent DC voltage.
The peak AC voltage is 1.414 * Vrms
The mean AC voltage is 0.9 * Vrms
This changes little when rectified to DC except for diode voltage drop.

So an 11V source will rectify to 10V.
It will have a mean voltage of 9V which is what you measure.
It will have a peak of 14V which is enough to slightly charge the battery.

To check the operation, you will need a battery but some indication could be obtained by putting a capacitor (1000µF or so) across the output to hold the voltage up between charging pulses.

RMS and peak voltage is giving me flashbacks of college (took electronics..got a technician diploma somewhere in the attic) just never got a job in it and moved on...lol.

Ok, so by just throwing the meter on the clamps might not be indicative of a working unit then, will have to hook it up to a battery and then take a measurement?
 

mursal

Dec 13, 2013
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Dec 13, 2013
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Yes, load it up and see if the battery voltage gradually increases above what it was before connecting the charger.
 

Black_Blade

Feb 16, 2014
7
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Feb 16, 2014
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right on..thanks so much guys for the help, will post a follow up when can get it back to the shop and find a battery to hook up.
 

carlosboyd

May 18, 2022
12
Joined
May 18, 2022
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Our Solar Octane battery charger had its pcb board come loose inside the case and it shorted against something when it fell. I ordered a replacement board for it but it seems there is something else wrong with it for it only puts out 9 volts on two of the three switch postions (2 A 12 volt, 10A 12 volt). The car start position still puts out 12 volts. I don't have a battery at the moment to place a load on the charger for testing purposes, just putting my meter on the output clamps. Would anybody have an idea of what I could check next? Would the rectifier board be toast? Can I test it with ohmmeter before just ordering a replacement?

Was gonna upload the schematic but the single page pdf is 2.89 MB and too large for the file limits. Its a OS6110 wheeled charger. Wiring diagram I downloaded was from this site:http://www.tesstools.net/OS6110_1330_Parts_List_s/2036.htm
EBL AA 1.2V battery
Also wondering if there is a way to test the rectifier and transformer on this unit, to see if its the culprit?
Our Solar Octane battery charger had its pcb board come loose inside the case and it shorted against something when it fell. I ordered a replacement board for it but it seems there is something else wrong with it for it only puts out 9 volts on two of the three switch postions (2 A 12 volt, 10A 12 volt). The car start position still puts out 12 volts. Would anybody have an idea of what I could check next? Would the rectifier board be toast? Can I test it with ohmmeter before just ordering a replacement?
 
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