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rustyrod

Senior Member

Joined: 08/11/2014
Location: Australia
Posts: 121

Posted: 05:21pm 24 Feb 2015

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I decided to shift some batteries around and tidy up a few wires.

I wanted to put this Solar 30 from the 24 volt circuit onto a new 12 volt setup to run the NBN dish and the phone so when the grid goes out I will still have a phone connection.

Did you all know the plug that comes in the packaging is not for soldering some sensor to - IT IS THE SENSOR !

I disconnected the batteries and ran in new wires then much later I realized one of the wind gennys and a 200 watt panel was still connected, I took them off and connected the 12 volt batteries then the 2 by 90 watt 12 volt panels

Looking at the display it was blank.

What? This has been on 24 volt for a few years, working fine.
Does it mean when I first connected it, it had configured itself to 24 volt and that�s that?
Reread the manual, no help there.
Can�t be, can it? Searching the WWW there is no reference to a reset or a fixed voltage.

I connected it back to 24 volt and still nothing.

Damm, the wind was really strong so I suppose 60 volt or more has fried it. Live and learn.

I was so depressed I went and watched TV and ate chocolate.

Later I was looking at the batteries and they were gassing?
I dashed back to the controller and the display was still blank.

Grabbing the multi meter I found the solar panels were charging through the controller.

Perplexed.

That night I pulled it apart and by examining the board I could see a 48 leg ic connected to the display.
46 of it�s legs were connected to �things� on top of the board and 2 connections went through to the other side.
One connected to negative and the other to lots of �things�

OK, I hooked up a battery and started measuring.

Nothing at the ic leg or on the print circuit.

With much twisting and eye strain I followed the print circuit back to a 3 leg �thing�

The 3 leg �thing� is probably a voltage regulator. 1 leg to positive, 1 leg to negative and 1 to the print circuit.

Great. 12 volt input -11.9 on output. But there was nothing on the print circuit going to C1 and R6.

�Curiouser and curiouser� said Alice.

Why is there voltage on the regulator leg and nothing on the print board?
By carefully placing the meter probe on the solder tab directly below the regulator leg;- TAA DAA nothing.

I pushed down a little harder on the leg and PRESTO the display came on.

Close examination showed it was not soldered when the surface mount regulator was installed.
I wonder how many more did not solder?

A quick solder and it all works.

How did it work for years?
Did the higher voltage cause the regulator to heat up and lift its leg ?

Lesson learned;- Disconnect the panels/gennys first before the load of the batteries.
I may not be so lucky next time.

Always Thinking

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 07:52pm 24 Feb 2015

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Good fix mate

I use the left shoulder fix for Chinese things

All the best

Bob

Foolin Around

Pete Locke
Senior Member

Joined: 26/06/2013
Location: New Zealand
Posts: 182

Posted: 11:30pm 24 Feb 2015

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Nice find indeed. Your eyes are better than mine :-) The 'THING' is an NPN transistor configured as a common emitter regulator (not knowing the circuit at all but with an experienced eye) and a give away is the Z2, CZ2 and possibly R6 as part of it. But yes, components not soldered to the board will lift after time with heat and vibration. Well done.
Cheers
Pete'.

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