Monday, September 26, 2005


Solar Tour

The Washtenaw County solar tour will happen on October 8, and my house will be on it! Please come!

There will be other tours around Michigan on October 1 and October 8.


Simplified battery watering

I ordered the Flowrite Profill battery watering system last week. It arrived on Saturday, and I was able to connect it up in about 20 minutes:

Special caps replace the original battery caps. Each cap has a float which cuts off the flow of water when the cell is full. The manifold distributes the water to the three cells in each battery.

The battery manifolds are connected together with rubber tubing. Each manifold has three connectors. The unused connectors are capped off.

A hand pump is connected to the manifolds with a simple connector, and the other end goes in the bottle of distilled water. When the pumping gets hard, the batteries are full.


Six weeks, six kilowatt-hours

Even last year, after substantial conservation efforts, I was still using about seven kilowatt-hours of grid power a day. Now, with the sun providing most of my electricity, I'm down to one kilowatt-hour--per week!

August 14:


September 25, six weeks later:


Monday, September 12, 2005


Shingle wiring

I finally got around to making a schematic of how the shingles were wired together in the attic. Here it is:

Click here for larger version.

Tuesday, September 06, 2005


Solar Tour

The solar tour is officially scheduled for October 8, and my house will be on it. Unfortunately, that is the day of a U of M home game (vs. Minnesota at 1 PM), which will make it more difficult for people to get around town. My house and several other sites are on the north side of town, away from most of the traffic, so please come if you can! I'll post more details when I get them.

Friday, September 02, 2005


Winverter software

I've got the Winverter software working on my computer now. When connected to the RS232 port on the Outback Mate, Winverter presents a graphical representation of what's happening with the charge controller and inverter. Here's a screen shot:

Winverter is available from RightHand Engineering for Outback and Xantrex equipment.

Thursday, September 01, 2005


Two months of solar

I went through the charge controller's log of daily solar power received. Here's the chart:

  1. The first week or so I didn't have a functioning "Mate" controller, so I couldn't get the inverter to run in HBX mode, which allows for automatic switching to the grid when the battery voltage drops below a certain point. Since I was using the crummy old batteries at this point, I was restricted largely to using solar only when I was home and the sun was shining. That's why there are four approx. 1 kwh days in early July.
  2. The high daily value for the two months was 10.2 kwh. This was the result of not only the extended high-angle sunshine available in early July, but also because the shingles put out more than their rated 17 watts each when they are new.
  3. The new batteries were connected on August 12.
  4. This shouldn't be taken as a direct measure of how much solar power was available each day. If the batteries were fully charged and not many loads were running, the amperage will drop to a trickle or stop altogether, even in full sunlight. Once we figure out the dump load, there should be less wasted power.
  5. The average daily power before 8/12 was 5.47 kwh; after 8/12 it was 6.65 kwh. This occurred even though the days are getting shorter and the shingles newness is wearing off. (I think we've had more cloudy and rainy days, too.) This shows that I needed adequate battery capacity to take fuller advantage of the solar power available. With the old batteries, I was generally unable to use any solar power at night--the batteries discharged quickly, and that was it. With the new batteries, I can power the house all evening and through the night, leaving the batteries ready to receive more charge the next day.

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