Ghurd's Controller for Remote Dump

[snowcrow]

  In the last few weeks I've been collaborating with Ghurd on a modified version of his Dump load controller for a remote dump load. The remote dump load in my case is a hot water heater, (600W element), located in my camper, about 20 to 25ft away from the battery bank. The signal to the IGBT gate will go through a snap disc thermal cut-off to prevent over heating the water. A second controller will then take over dumping power to another load.

 The idea is to have the IGBT tap power from the main feed to the camper, instead of running more heavy wire and just use an old 14 awg 3 conductor extension cord to operate the gate. I'm not sure yet how remote I can go with the dump load, I'm still in the testing stage.

  Below are a few picture and captions to describe what has been done so far.

  Above is the main controller and the remote P-fet board.

  Above is the IGBT, remote P-fet board, and a bit of the load resistor (seen top right).

 As you can see on the controller board above, R4 has been replace with jumper and R5 and the P-fet have been removed, now located on a remote board near IGBT and load. The trim pot is on the other side of the board, to make for easy mounting to the faceplate.

 The remote board above contains a IRF9Z34N P-fet and C2 220uF 50v (NEW), for reliable firing of the IGBT.

  Above is a picture of IGBT, remote board, and R5. The IGBT has two devices but, only one can used at a time. As you can see the unused one is shorted out to prevent firing.

 And here is the faceplate I am using to finish it all off.

 I hope I didn't forget anything!!  It's only been tested with a 10 amp battery charger so far but, its working great so far!!  I hope to be testing it with my 10' wind mill in a week or two, I'll keep you all posted on my progress.

Blessings, Snow Crow

[commanda]

Just something to consider;

The long lead to the IGBT gate will act as an aerial, to both RF and lightning.

Shielded cable and filtering would be on my to-do list.

Amanda

[snowcrow]

  Thanks Amanda, that would be just one of those things to drive a person crazy trying to find the problem too!!  I can see where a near by Ham set or frequent lightning could cause a problem, specially so with a longer run!!

Blessings, Snow Crow

[Drives]

An observation,

The IGBT is overkill, but I would still mount it on a heatsink with compound.

I believe many people would like a schematic view of your circuit, could you post one?

Looks like fun.  :-)  

[snowcrow]

  My system is 12v and will producing a lot of amps, thats why I'm using a IGBT.  I do have a large heat sink for it, it just wouldn't fit in my scanner.

  Here is a schematic Ghurd had drown up for me.

Blessings, Snow Crow

[ghurd]

It amazes me people can build something with the "schematics" I make.

As long as the smoke stays inside...

G-

[coldspot]

ghurd- (He's the man,.!!!)

snowcrow-

 Very nice!!!!!

Just what I needed also.

 I just got a 600 watt 12 VDC element a few weeks back.

 I should be getting my travel trailer in the next couple weeks and then I'll have more places to use all the stuff I have been getting and building.

 A question:

"A second controller will then take over dumping power to another load."

 I'd like to know more about this.

 If you could, please.

   Thanks

[snowcrow]

  Hi coldspot, Well.. I had two methods in mind really.

  In the first one, if producing <600 watts, I would use just one dump controller, as show above. I would replace the thermal cut-off snap disc on the tank with one that is a SPDT snap disc (same temp. value) and use it to switch the output gate signal of the controller between two IGBT's with they're own separate loads.

  Method two, if producing >600 watts, I would use two dump controllers, as pictured above, each with its own IGBT and load. This is the method I'll be using.  The primary dump load will be the 600w heating element and the secondary will be a bank of five 1.2 Ohm 300w resistors, connected in parallel.

  Hope this helps!

Blessings, Snow Crow