Suburban Off-Grid Power Source

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I have been using this system as a way to self-learn about off-grid wind and solar energy with the intention of building a much larger system after I retire. I started with 4 x 200W panels. I recently added two more.

I had been using an unbranded, Chinese MPPT charge controller, but it did not take in any higher voltage from the panels than was sent to the batteries. This drove the amperage from the panels up to 20-22 A. When I added the new panels, It would not take the power from them. It actually generated slightly less wattage.

So I took the wind offline and have it presently set in its own circuit charging a car battery. You can see the presently-disconnected dumpload wires in this photo. The wind charge controller is under the Victron, and it is now connected to a car battery, which is not in this photo so you can see the rest of it.

Power Wall - 090524 - 03
Power Wall - 090524 - 032048Ă—1152 348 KB

The 2 smaller panels are the most recent additions, and with them and the Victron, which is performing swimmingly, I have had 13 3+ KWH days out of the past 35, compared to 16 out of the previous 400 or so. With the Victron, I could conceivably add 2 more panels, but I don’t know where to put them on this platform. Any expansion of the platform would require a new CP.

Panel Configuration 090524
Panel Configuration 0905241584Ă—2048 452 KB
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4 Likes
2

Nice.
What is that big, green thing in upper right?

3

It looks like a high power resistor.

4

When batteries are fully charged, the solar charge controller just shuts off or throttles the energy coming in. It can do this because there are no moving parts.

However, the wind generator needs to have a constant load on it, especially during high winds because the load acts as a brake. You no doubt have seen large turbines spin apart during high winds when their mechanical brakes fail. Smaller turbines rely on the load to act as a brake.

So when the battery reaches full charge, the controller diverts the power to a “dump load.” The battery circuit is disconnected and the excess electricity is converted to heat. This prevents overcharging the batteries and protecting the generator from spin apart.

Mr. Borke is correct. It is basically a giant resistor. On a severe windy day, this can glow red hot. That is why it is mounted to an aluminum panel an inch away from the wall. This effectively burns off up to 600W of energy.