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Battery charger repair

Foggy54

Apr 24, 2017
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I am trying to repair my 25 year old battery charger
Question on the output of xfmr I have 29v, what I need to know is what type of replacement diodes do I need to get a proper charge voltage. 14vdc?

It's a 2-10-50 amp charger
21.7vac @2a, 25.6vac@10a, 28.7vac@50amps charge rate

At present it has common plate with 2 ea diodes in parallel from each xfmr leg 4 total

I hope I have explained this well enough.

Am I needing 1/2 wave rectifying? Help pleaseIMG_0434.JPG
 

Foggy54

Apr 24, 2017
8
Joined
Apr 24, 2017
Messages
8
P
I am trying to repair my 25 year old battery charger
Question on the output of xfmr I have 29v, what I need to know is what type of replacement diodes do I need to get a proper charge voltage. 14vdc?

It's a 2-10-50 amp charger
21.7vac @2a, 25.6vac@10a, 28.7vac@50amps charge rate

At present it has common plate with 2 ea diodes in parallel from each xfmr leg 4 total

I hope I have explained this well enough.

Am I needing 1/2 wave rectifying? Help pleaseView attachment 33499
Ps center tap going to neg. charger output..
 

duke37

Jan 9, 2011
5,364
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Jan 9, 2011
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5,364
There is nothing in your picture that can pass 50A, looks more like 5A to me.

Does it work?
You will need an external resistance such as a bulb to control the output current.
Do not use 1/2 wave rectification, this will put the transformer into saturation which will burn it out.
The original diodes were doubled to get current capability. You can now get large diodes at reasonable prices. I would look at a bridge rectifier block with only two of the diodes used.
 

Foggy54

Apr 24, 2017
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Apr 24, 2017
Messages
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There is nothing in your picture that can pass 50A, looks more like 5A to me.

Does it work?
You will need an external resistance such as a bulb to control the output current.
Do not use 1/2 wave rectification, this will put the transformer into saturation which will burn it out.
The original diodes were doubled to get current capability. You can now get large diodes at reasonable prices. I would look at a bridge rectifier block with only two of the diodes used.
they are called 50 Amp button diodes oem rr50

But I thought I could replace them with a stud mount type if I could figure the polarity
They are in the Schumacher se60 2/10/50 charger

These look to be epoxied on?
 

Foggy54

Apr 24, 2017
8
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they are called 50 Amp button diodes oem rr50

But I thought I could replace them with a stud mount type if I could figure the polarity
They are in the Schumacher se60 2/10/50 charger

These look to be epoxied on?
 

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Bluejets

Oct 5, 2014
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You originally said the common from the transformer was the negative charge lead so ....yes.
Diagram below
 

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duke37

Jan 9, 2011
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The diodes will not be epoxied on. The epoxy will not conduct electricity and will be poor thermal conductor. The original rr50 diodes are available at a reasonable price. They seem to be clamped to a backing strip with a spring to take account of thermal expansion.

I do not know what your meter should read. 0.69 V in the forward direction and infinity in the backward direction is what I would expect. Why was the puck dismantled?
 

Foggy54

Apr 24, 2017
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The diodes will not be epoxied on. The epoxy will not conduct electricity and will be poor thermal conductor. The original rr50 diodes are available at a reasonable price. They seem to be clamped to a backing strip with a spring to take account of thermal expansion.

I do not know what your meter should read. 0.69 V in the forward direction and infinity in the backward direction is what I would expect. Why was the puck dismantled?
When I was removing the spade lug it either was loose or I finished pulling it loose
 

Foggy54

Apr 24, 2017
8
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Apr 24, 2017
Messages
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Thanks for all the help guys I'll make a trip to the local electronics store and see what they have in the stud mount type.

I'll give bluejets idea a try even though the other oem hokey pucks are available. THANKS ALL john
 
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