I have been improving my 12v Solar power system to make it capable of adding more panels to. I beefed up my fused power distribution box. I built a Diode isolated panel combiner. So now finally I have rebuilt my Ghurd Dump Controller into a SuperController. Up until now I have been using this simple dump controller pictured below.
I was in a hurry to get my system working, and used some resistors I had on-hand to make this Dump Controller. The resistors are from an old audio amplifier. This system could dump almost 6 amps. It was perfect at the time but it's not really beefy enough to handle much more power than I am making now. Ghurd hooked me up with some real resistors and another Controller so I could make the GhurdSuperController.
This is my new 2 stage Dump controller already installed. It has 2 seporate Ghurd Controller Modules in it. The first stage can be set to start dumping at 14.5 volts, while the second stage can be set higher to start dumping at 14.7 volts. This makes it easier on the battery as large dump loads are not used until there is a large amount of power to dump. The resistors are hanging on 3/8inch threaded rod with little heatsinks made from big fender washers. The threaded rod is bolted tightly to the chassis which makes an it into an even bigger heatsink. The top row of resistors is Stage 1 and the 2nd and 3rd rows are Stage 2. The 12volt fan only operates when any of the 2 stages are dumping. The fan gets it's power through 2 isolation diodes that charge the Big Blue 10000mfd capacitor on the lower right.
I also made each dump stage adjustable with switches. Stage 1 can be set to dump at 3 or 6 amps, while stage 2 is settable to 6 or 12 amps dump. At this time I have everything set to minimum since I only have 3amps coming in right now, but I can really grow into some more Solar Panels and other RE inputs easily. I included On/Off switches on each stage too. This will let me operate the unit on either stage independently or turn them both off for Battery Equalization. The dump indicator LEDs are here also, plus there are LED outputs on the terminal strips for some dump indicators inside where I'm using the power at.
Here is "DanCADD" schematic diagram. It's hard to read but it's all correct. Except there are reverse Freewheeling diodes on each resistor bank to cancel out the possible Back voltage the coils in the resistors might create when being switched off.
- Results -
This has worked perfectly since the moment I installed it and switched it on. Of course I had to do some minor tweaking to get the 2 stages dumping at the correct voltages, but all the functions work just fine. When I switch between High & Low amp dump settings, the LED flashrate does not change, but the On-Duration changes. The cooling fan (.14 amp) will run usably for about 5 seconds after each dump pulse and the whole thing runs cool enough to touch, even directly touching the resistors that are continuously dumping. As I add more power inputs I will need to watch and see how hot it gets. it's max dumping ability is about 300 watts at 18 amps.
This Dump controller was built inside the metal cover for a thin-form UPS unit that had been toasted. You may notice in the second picture above that this controller is mounted next to my Diode Isolated Combiner unit built in the golden metal. That was the Inner Chassis of the same UPS unit.
About the time I got my controller setup properly, it has started clouding up early every morning, and threatening storms in the afternoons so I haven't had the fun joy of sitting here watching my dump lights flashing, which is much more fun that watching the panels themselfs.
Here is a link to my system in Oct. 2007, it has been much improved since then.
http://www.fieldlines.com/story/2008/3/4/6303/63451
Here is a link to Ghurds Dump Load Controller, I highly recommend it.
http://ghurd.info/
W o o f -={(
