power filter for my old Magnatek

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magconpres

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Jul 29, 2008
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53
Last year I purchased an ARP controller for my fridge, but due to the unfiltered dc power from the converter for the fridge circuit, it would never work on shore power.

The easy fx would be to connect the fridge to one of the filtered circuits, but I decided to have some fun and build a filter for it.

I built s simple circuit using some components I had around from previous electronic projects.  The circuit is basically an LC filter, also known as a tank circuit.

Before and after pics of the voltage will be posted later.  They have to be resized first.  Before adding the filter, voltage would cycle between 0 and 19, with an average around 12.4.

After the circuit, the voltage is a steady 19 with very little ripple (about .3v)

I'm going to tweak the circuit a bit more to bring the voltage down to about 12.5.

The ARP is much happier. Before, the display was unintelligible  on shore power. Now I can read it, but it flickers a bit.  Probably because the voltage is a  bit high, or maybe .3v is still to mich ripple for it.




 

magconpres

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Jul 29, 2008
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Pics....
 

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Gary RV_Wizard

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12.5v is kind of low - should be at least 12.6  (12v battery voltage) and 13.1-13.3 would be more effective and well within fridge & ARP operating range.

Curious why you haven't replaced the old Magnetec by now.  Your batteries will love you for it and no unfiltered circuits to cause headaches.
 

solarman

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Feb 8, 2018
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Texas
magconpres said:

good grief.. I would have replaced that converter a long time ago.

I would consider 500 mV pk/pk as only just acceptable !
 

John From Detroit

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Apr 12, 2005
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Location
Davison Michigan
A better solution would be a Progressive Dynamics 4600 series to replace the back part of the Magnetek (the electronics part) or fi the magnetek is nto part of the power distro panel the 9200 series.

But what you need is a voltage regulator.. Not sure the amprage needs of the unit but let me look up a regulator for you.

Found a bunch of them
All electronics Catalog Page

Make sure the unit you get has at least 1.25 times the current rating the board needs.
 

magconpres

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Jul 29, 2008
Posts
53
thanks John.
I suspect you are right about the regulator.  I think I have some lying around somewhere, or can pull one from something in the parts bin.

As fas as why I'm not just upgrading the converter, I dont' use the RV much.  Maybe one or two times a year, so I don't wan't to put much money into it.
 

John From Detroit

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Davison Michigan
Smaller are less expensive. a Brand New Factory Reman Progressive Dynamics straight from PDI. 238 Dollars out the Parts/Service department door last year.  (yes I happened to be passing by after my original failed and frankly it was the Best supplier literally FEET out of my way)

Smaller are cheeper

That same converter. New. just shy of 400 at the RV dealer down the road from where I'm parked.
 
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