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Forum Index : Electronics : Bench Power supply Extender

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Tinker

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Joined: 07/11/2007
Location: Australia
Posts: 1904
Posted: 02:40am 15 Feb 2016
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Many Bench Power supplies, including mine, only go up to 30V DC. I required 48V to test something I was working at.

I used 4 small (4Ah) gel type 12V batteries in series and while that worked it was awkward to set up and not really adjustable.

Looking at E-bay for an alternative I found this: step up module

and ordered one.

To make this module more user friendly I fitted it into a diecast box.




I should have used a bigger box, it was a tight fit. The finished item looks like this.




Testing it all out it worked fine after a little hiccup (more about that below).
The output with a 150W load gave this trace on the scope.




The scale is 50mV/div, I think those little spikes could be easily removed with a series choke if so desired.
The larger potentiometers make it easy to set the unit, I particularly like the current limit feature which works well.

The hiccup; Having a quoted capacity of 600W I tested it for that, using a 24V battery at the input side and a large wattage resistor as load.
Unfortunately at one stage the load got too great (I confused the input & output Amp meters) and the fitted 15A fuse blew. Too bad it took the input power Mosfet with it.
I found a suitable replacement Mosfet and its now working again. I did replace the 15A fuse with a 10A type and would recommend doing the same.
Klaus
 
Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5117
Posted: 01:09pm 15 Feb 2016
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Nice find Tinker. Yeah a choke and a few low ESR filter caps on the output would help.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
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