Dump Load Controller

[valterra]

I built a Dump Load using Glen's Dump Load Controller Kit.

I mounted everything into an old UPS case.  It dumps to 8 1 Ohm, 10W resistors.

Here's a shot of the inside.

The back connects to the battery bus via a standard AC power cord.  The good thing about this is that you can't plug it in backward.  But I still put a big red mark, as you can see!  The bad part is that you end up creating a "widomaker" cable (AC plug on one end and bare wires on the other), so be sure to keep this one either hooked up or LOCKED up!

The two LEDs sort-of fit into the holes used by the UPS's original LEDs.

Here is a shot of my two Golf Cart Batteries and 3 of my HF DMMs.  The first one measures Wind Amps, the second is Solar Amps, and the third is the Bus voltage.

By the way, there's a magnifying glass logo toward the top right of those pages, if you want to get a big version and "look around" a bit.

After I first set it up, I admit that I was a little disappointed.  When it dumps, the yellow light comes on.  Big whoop.  No beeps - nothing but a light.  I thought about hooking up a piezo buzzer or something, but I figured that would get annoying after awhile.

The only noise is a very fast, very VERY soft fast clicking sound.  I couldn't figure out what is was, so I took it apart.  It's the resistors.  They make a very small click when they get activated.  And when this voltage is on the border line, it happens a lot.  You have to listen very closely to hear it.

So right now, with no loads attached, when the wind kicks up, so does the yellow light.  The resistors get hot - sometimes very hot.  They actually started to (barely) soften the plastic of the UPS case!  :-)  

Glen, I want to thank you for making the world's most BORING, but LIFESAVING, invention.  :-)  

[commanda]

Please do the world (if not yourself) a favour, and invest in some Anderson Powerpoles.  The life you save may be your own.

And look for a metal case and a fan.

Amanda

[ETech]

Let me start off by saying that I understand the amount of effort that you put in to you construction.

I observed some problems with you construction:

When you heat plastic it will out gas nasty chemicals. When you heat it up enough it becomces a fire hazard.  The dump resistors laying in the case will provide a great amount of heat.  Ways to improve on you construction:

1. Mount the resistors vertically using metal stand-offs.
   
2. Spread the resistors apart to provide better air circulation around them, this   will allows heat to transition to the air better.
   
3. Provide lower and upper air vents to remove the heat from your box.
   
4. A fan to remove heat from the box would also help. I can be connected across the resistors so it's only on when the resistors are being used.
   
5. If you continue to use the plastic case, it where you will not be breating the out gassed fumes. For fire issues I would us a metal case, try an old PC power supply case.
   
   

For safety reasons you should never use AC outlet for anything except for mains / line power. Sooner or later someone will plug an ac cord into it, then you have a safety hazard & smoke machine.

A good (cheep / easy) alternative is a terminal (barrier) strip.

They are found almost everywhere, and are easy to wire. Drill a hole, push you wires through, solder / splice lugs, then label the connections.

I hope that these suggestions will help you improve you design, and that you and yours stay safe and happy.

[valterra]

Eventualy I plan to mount everything - meters, bus, dump load and controller into a single box.  I have an old PC tower boxes that should make for a nice solid unit.  Also I can "tap" the metal's heat-sinking ability where necessary.

That being said, I also am currently dumping way too much.  Better balancing of loads should keep things cooler.

A point of clarification here...  I am only using the FEMALE AC "jack" here.  No danger of something getting plugged in.  Even a direct short shouldn't be a problem.  Worst case scenario would be exactly like touching the two male ends of two appliances' cords together.  What happens?  Nothing!  The "widowmaker" cord is obviously a problem.  But to a lesser degree, so is anything hooked up to 200 amps of dc.

[wooferhound]

If those are the resistors that ghurd has been selling with the kits

they are 10 ohm, 25 watt resistors

4 resistors paralleled = 2.5 ohm 100 watt which is a 5.5 amp load at 14 volts

so it would be dumping 77 watts per 4 resistor set at 14 volts

both sets would be pulling over 150 watts which will get rather hot

How much power do you have coming in ?

[valterra]

Right now, on a crazy windy and super sunny day, I get about 3A from wind and under 3A from solar.

This thing does a lot of fluttering like ghurd said it would.  If the batteries are fully charged and there are no loads, you can watch the yellow light to determine what the wind is doing...

dark...

blink..... blink.....

blink blink blink

buzzzzzzzzz

then ON Solid

(this is all very quiet actually)

then go reverse through the steps.

lol.  I should make a short video of it.  Glen sure made an awesome little circuit here.

As early as tomorrow, I will have some actual, legitimate full time loads on it.  DSL router at 12vdc and network hub at 12vdc 1.25 AH according to the label.

Then everything will be better balanced and it won't dump so much.

We'll see!

[valterra]

and if it isn't  windy or sunny for too long, I will have to get my lazy fat a-- up onto te treadmill that I just hooked up.  I think I peak at 5 amps on that beast.

[ghurd]

Seems like a lot of heat in a little box, more so in a plastic box.

But it's a nice start.

It must have taken quite a while to get those batteries up to 14.5V.

G-

[valterra]

funny you say that.

They were 12.x when I got them.  I think it took about 2 full days.  

I did notice that, like I believe I've read here before, that once they're  almost full, the voltage takes FOREVER to climb.

Thanks again Glen, for everything!