Newbie assembling ghurd's controller

[(unknown)]

The system will consist of a small wind turbine and 1 (or 3) solar panels.

I made a small ugly sketch from what I understood from ghurd's schematics and I was wondering if you guys could have a quick look and tell me if there's any obvious error?

Also, I was wondering where do you guys put the dump loads N-Fet and the solar panel's N-fet?


Thanks!

link your pic was way to big to display here was bigger than me screen is wide people would have a fit.
Kurt

[ghurd]

The sketch is good.

"Where" depends on the physical stuff.  Where does it fit, where it won't be in the way?

But not in the controller box if the controller is in a little plastic box.

G-

[wooferhound]

I built a dump load using 2 of Ghurd's controllers for two stages of dumping.

here are the details and pictures . . .

http://www.fieldlines.com/story/2008/7/13/211414/932

[(unknown)]

Thanks Ghurd, helpful as always

Woof:  Thanks for the link.  I did give it a look and learned a lot since I'll be using the same power resistors.  

Looking at your pictures I finally chose my dump load's enclosure :  a thin aluminium box for president's choice "Belgian Milk Chocolate Fingers" ...lol. . it's about 9.5" x 4" x 4" and seems to be aluminium.  I'll put 2 rows of 4 resistors on one level and another row of 4 a bit higher.  

Do you think I can put my 3x power FET in there or will it be too hot?  Guess I'll try  and see.

Cheers!

[(unknown)]

Setback!

I made magic smoke out of my "Ghurd Variable Voltage PS (TM)" today.  Oops.

[willib]

Did you really mean that you were going to short the solar panels ?

Maybe you meant you were just going to disconnect the panels from the batteries when needed?

[wooferhound]

I was wondering why it's necessary to do that with the solar input. I would hook it up like this.

http://www.fieldlines.com/images/scimages/231/HookUp.GIF

[bj]

Nice one-liner Woof.  Even I can follow that one.

[ghurd]

The solar is 3 x 70W, 210W, or about 4A each.

The windmill is about 100W.

This one takes 1/3rd the dump load size/cost if the individual PVs are shorted instead of dumped.

I do not expect the dump load to operate often.

There will (probably) be a Pre-Dump-Load load to use some of the power before the dump load is active, sort of like an LVD except set to a much higher voltage.  The 2nd load will help keep the battery voltage under control, but not enough control to do away with the dump load.

It's a lot easier to short the PVs than to disconnect them.

Here is some old discussion about shorting vs opening of PVs,

http://www.fieldlines.com/story/2008/12/24/162442/74

G-

[(unknown)]

Nice graph Woof.

One question though: I'm quite sure I read a post by Ghurd somewhere saying that the controller's "battery sensing" wires  and the dump load's "power" wire  needed to be separate.

 That would be  to prevent the controller from sensing the voltage drop from the dump load's start and shutting it down immediately, or something along that line.

[(unknown)]

That is why.  Now everyone know I didnt think that up myself, thanks Ghurd

[Ungrounded Lightning Rod]

(Presuming you've already got blocking diodes on your solar panels to prevent leakage discharge or other issues.)

A switching transistor will have a voltage drop.  Putting one in series will waste some power when the panels are "on" - when you want to keep as much power as you can.

Using a transistor to short the panels means you dissipate power in the transistor (plus a whole bunch in the panel) when the panels are "off" - when you're trying to throw the power away.

Any power you don't pull from the panels ends up as heat in the panels.  So shorting them doesn't heat them any more than leaving them open (or otherwise disconnected) in the same sunlight (though the heat is distributed a little differently).  No harm comes to the panels from shorting them.

[(unknown)]

From my understanding the  FET will be in parallel with the normal "on circuit", meaning it shouldnt lead to a voltage drop.

.. right?

[(unknown)]

Alright, the variable voltage PS has been fixed, and I've put two of ghurd's controller and a car voltmeter in a small radio shack enclosure (http://www.thesource.ca/estore/product.aspx?language=fr-CA&catalog=Online&category=Project_B
oxes&product=2701803)

I've also been "Freecycled" a Metal "home alarm system" panel.  The panel is metal, painted gray, and is about 13"13"*4", with a hinged door.   The non-working circuits (including a few terminal strips and an angled aluminium bar screwed to the panel's wall to act as a heat sink) were also included.

My question:

I was originally intending to use this only as a box for my dump load, much like Woof did here (http://www.fieldlines.com/story/2008/7/13/211414/932).  

However, I was thinking about it and realized the panel is much larger than what I need just for the resistors, and I still need a place to put the following:

-1 wind turbine blocking diode, with heatsink

-3 solar panels blocking diodes, with heatsink

-3 solar panels "IRFZ44N", with heatsink  to short the panel when dumping load

-2 of Ghurd's "Fancy Fet's" , *without? heatsink controlled by 2 different LVDs : to control loads (one being a pump running from 12V and up, the other being a pump running from 13V and up)

-1 of ghurd's LVD controllers.  (my other 2 being in the radio shack enclosure outside of the panel)

Do you think that adding these to the usual dump load stuff (12 resistors, 1 computer fan to cool  them down, 3 "IRFZ44N" to control them)  would make  the panel too hot for the fets?

Thanks

[(unknown)]

Finished my controller box.
1 dump load controller (left, set at 14.4V)
1 LVD controller (right, set at 12.2V)

LEDs are on.


 http://i922.photobucket.com/albums/ad62/morglum82/PICT5698.jpg

[wooferhound]

I made a separate box for all of my combining stuff. Don't put too much stuff in the same box, it won't be so easy to change next time . . .

http://www.fieldlines.com/story/2008/6/24/0179/40235

[TomW]

Woof;

I would also add:

Label everything possible.

It can save a lot of time in the future.

Not that I do it. That would just be too smart.

Tom

[(unknown)]

Good idea, I'll do that.

I've just built a dump load box from an aluminium cookie box and will use the alarm panel for distribution   from the wind/solar    and to the loads (dump,pump1, pump2)

Basically, I would try to combine your Diode Isolated Input Panel you mentionned above (http://www.fieldlines.com/story/2008/6/24/0179/40235)  and the Fused Power Distribution Panel (http://www.fieldlines.com/story/2008/6/7/21233/94327)  into one single panel.  Or maybe keep them separated as I was just given an old home-brew stereo receiver with a large steel case that could be used for either the diode panel or the distribution panel.  For for thought.

Anyway, I have few questions, just to make sure I get it:

1a)I was wondering if there is any reason for not combining thee 8x 12 gauge wires going from the "Fused Power Distribution Panel" to the battery into one large wire?  If not, do you have any idea how I could combine so many wire into a large 8 gauge wire I have around?  I can't seem to thing of any good way...

1b)I remember reading that the ghurd dump load controller must have it's own wire going from the battery and not using the same wire than the dump load.  I guess that means I would use one large wire for everything but the controller, and another one for the controller.

2)Do you combine the input from all the solar panels and the wind turbine in the "Diode Isolated Input Panel" before sending it into the  "Fused Power Distribution Panel" (terminal #5) ?

3)Just so I understand, your  "New 12V fused distribution panel"

(http://www.fieldlines.com/story/2009/3/18/232910/066), is at the point of use, but you still have the "Fused Power Distribution Panel" by the battery, right?

[wooferhound]

I think you know that I use the 12vdc power directly without an inverter

1a -  The battery must be fused as close to the battery as possible. If something were to short-out there would be a huge wiring fire as the battery will be capable of delivering over 1000 amps into a short circuit so I have a fusebox at-the-battery to fuse everything going In & Out of the battery to prevent shorts from causing fires.

It is fine to use a single conductor to go to the battery, I just happened to have all of that 12ga wire so I ran a single wire to each fuse in the distribution panel as it was so easy to solder a single 12ga to a fuse holder. All of the wires are combined at the battery Terminal. All other wiring in my system is 12ga so this is working fine.

If you want to combine wires to go to the battery, use a terminal strip. Combine all of your wires at the battery terminal clamp, run them to a larger 2 terminal strip in your fusebox, then spider out smaller wires from the strip to your fuseholders.

1b - The Ghurd Controller does need two separate wires going to the battery. the Voltage Sense wires need to  be completely separate from the rest of your wiring and go all the way to the battery terminals. The sense wires can be very small but you need to fuse the Sense wire properly for the wire gage you use.

2 - I combine all of the solar panels and send them through 1 wire to fused Terminal #5. I don't have my wind power up yet but it is a 2 phase machine (single phase center tapped) and they will be combined and sent through a different wire to the (now unused) fused Terminal #6.

3 - I have 9ga wire coming from the Battery Fusebox 110 feet to my computer area where I use the power. This wire is good for over 40 amps but I have a 20 amp fuse on it at the battery. If my system expands, I will be increasing the fuse for this long wire run. Under my computer desk is a second fused distribution panel with capacitors to help prevent power surges. Most of the wiring past this point is 18ga (7 amps) & 16ga (10 amps) wire, so I must provide fused outputs to these smaller wire runs. Right now I have four 5 amp fuses in this box. If I didn't fuse this smaller wire, then they would be protected by the Large Fuse in the Battery Fusebox making another fire hazard.

Helpin' best I can . . .

[wooferhound]

Absolutely Label Everything

You won't believe how much you will forget about something you built.

and use terminal strips for all the Ins & Outs. You will want to change and expand things and it becomes very much easier

[(unknown)]

Thanks for this!

I'll make sure to post pictures when I'm done.

Will be a while though, soon leaving for a month in Eastern Europe/France !