Author Topic: 12 Volt MacTools Battery Charger Rectifier  (Read 8755 times)

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behoof

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12 Volt MacTools Battery Charger Rectifier
« on: May 11, 2010, 12:03:36 PM »
HI all,

I  have a question for you guys about a couple of rectifiers for 12 volt battery chargers I have... they are both MacTools BCH-066 model...
 
Both have bad rectifiers and I can't seem to find the ones "for" these chargers anywhere... here's a link to a company that at least shows the rectifier.
 
http://www.centurytool.net/865_679_666_Rectifier_DISCONTINUED_No_Replacement_p/865-679-666.htm
 
My question is, do you have any idea of what I can do or use to get these two chargers going? They're both great units but did get a bit old ahem...
 
Appreciate any input you could share.

The rectifiers are 2 square plates about 5" square with an insulated bolt thru the middle of each plate and discs on each plate... also has 3 tabs for the wiring hook ups and a nut to tighten a wire to the stud that holds all this together.

behoof
They're in the wire!!

bob g

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Re: 12 Volt MacTools Battery Charger Rectifier
« Reply #1 on: May 11, 2010, 12:15:38 PM »
i don' t know how old the charger is, but what you are describing sounds like "selenium" rectifiers
and yes they were common in battery chargers years ago

you could replace them with HD diodes, but the voltage drop is higher with selenium than it is with silicon
so the chargers might charge a bit harder which generally isn't an issue unless you use the charger for
long term unattended charging.

bob g
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large frame automotive alternators for high output/high efficiency project X alternator for 24, 48 and higher voltages, and related cogen components.
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TomW

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Re: 12 Volt MacTools Battery Charger Rectifier
« Reply #2 on: May 11, 2010, 12:24:23 PM »
Hoofie;

Rectifiers are rated for volts and amps. I suspect you can use anything rated for the same values as the original and be fine. How old are these things?

I probably have some diode packs that would work but without knowing if it is just a single rectifier or a bit more complex it is hard to say..

Finding that style is unlikely but you can wire in other components and it should work. Got a photo of how it is installed?

If I had time for IRC I would tell you to pop in and we would sort it out but I don't get on live much lately. Others could help there, too,  I am sure.

Simple answer:

I think we could make them work again. Assuming all that is wrong is the rectifier. We could figure that out for sure pretty quick on IRC, too.

Tom

behoof

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Re: 12 Volt MacTools Battery Charger Rectifier
« Reply #3 on: May 11, 2010, 12:27:25 PM »
Thanks for the reply Bob_G... gonna jump into IRC and see if the guys there have a solution for this "non-EE" guy...

Skip



i don' t know how old the charger is, but what you are describing sounds like "selenium" rectifiers
and yes they were common in battery chargers years ago

you could replace them with HD diodes, but the voltage drop is higher with selenium than it is with silicon
so the chargers might charge a bit harder which generally isn't an issue unless you use the charger for
long term unattended charging.

bob g
They're in the wire!!

behoof

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Re: 12 Volt MacTools Battery Charger Rectifier
« Reply #4 on: May 11, 2010, 12:29:56 PM »
Tom,

Gonna do just that later this evening or first thing tomorrow... IRC here I come ...

Both of these are identical and are 3 tier chargers... I'll get all the specs on them for my quest...

Thanks again,
Skip

Hoofie;

Rectifiers are rated for volts and amps. I suspect you can use anything rated for the same values as the original and be fine. How old are these things?

I probably have some diode packs that would work but without knowing if it is just a single rectifier or a bit more complex it is hard to say..

Finding that style is unlikely but you can wire in other components and it should work. Got a photo of how it is installed?

If I had time for IRC I would tell you to pop in and we would sort it out but I don't get on live much lately. Others could help there, too,  I am sure.

Simple answer:

I think we could make them work again. Assuming all that is wrong is the rectifier. We could figure that out for sure pretty quick on IRC, too.

Tom

They're in the wire!!