The Straw House Blog

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New Panels

Last month we installed two more 175W solar panels to our array. For those keeping track we now have eight 85W BP solar panels, four 165W Sharp panels, and two 175W Sharp panels for a grand total of 1360W.

Unfortunately one of the realities of building an array piecemeal is that the sizes of the panels change from model-to-model and year-to-year. We really didn’t want to buy new racks so we decided to modify the existing racks that hold the BP Solar panels. We added two new mounting rails and moved the two existing rails to the sides. The new panels squeeze quite nicely in the middle.

This required that new holes be drilled to mate the horizontal rails to the rack uprights. If you look closely you can see a piece of wood we were using a blocker to prevent us from accidently drilling into the back of a panel. With Dad, J.P. and I it took most of the day to get the racks modified, panels mounted and wired.

Most of the time that we worked Declan played outside in the sand pile (side note: a pleasant side effect of straw bale construction is that you usually end up with enough leftover sand for a good play area.) He’s a remarkably self-sufficient kid.

We’ve been really lucky, so far this fall and we’ve had lots of sun. We call this time of year the “100 days of grey” because we typically go from late October to early January with little or no sun. In the last four weeks we’ve had many sunny days and have really seen the benefit of our new panels. Here’s a picture of the readout form our Outback MX-60 charge controller. You can see that the panels are bringing in 31.4A but the MX-60 is upping that to 38.3A. Typically we have to run the generator weekly through the 100 days of grey to keep the batteries charged but in the last four weeks we’ve only run it twice. In addition to saving money on gas, we really appreciate the peace and quiet.

     

July - August 2004 Solar Stats

It’s been a pretty crappy summer, and I’m saying that as a guy who doesn’t even really like summer. It’s been rainy, cloudy and cold. We openned the top windows once and within three days had the ladder back out to close them again. Whereas last year we were sleeping with the sliding doors and side windows open this summer we’ve mostly kept them closed. A friend was saying that we’re going to have a really cold and snowy winter but this summer has been so weird I can’t help but wonder if there isn’t a reasonable chance that it’s going to be 30C in December.

June Solar Stats
Monthly Total: 1225.3 AH
Daily Average: 40.84 AH
Best Day: 54.7 AH
Worst Day: 19.3 AH
Days Below 5 AH: 0

July Solar Stats
Monthly Total: 989 AH
Daily Average: 31.9 AH
Best Day: 57.6 AH
Worst Day: 0 AH
Days Below 5 AH: 0

I haven’t been very disciplined about my record keeping this summer so there is some margin for error in those stats. They look about inline with last year though; June was better with 1225.3 AH versus 1174.8 AH (based on daily average for June 2003. July is a bit down with 989 AH versus 1066.8 AH for 2003.

     

March to May 2004 Solar Stats

This May was our one year anniversary in the house. I can barely articulate how much we have learned in the past 12 months. It has been a fantastic experience, and, notwithstanding the birth of Gil, probably the best year of my life.

We’re quickly coming to appreciate that the spring is a great time to be living off grid; we’re getting appreciable amounts of both sun and wind.

March Stats
Monthly Total: 718.3 AH
Daily Average: 23.17 AH
Best Day: 58.5 AH
Worst Day: 0 AH
Days Below 5 AH: 4

April Stats
Monthly Total: 1011.4 AH
Daily Average: 33.71 AH
Best Day: 63.7 AH
Worst Day: 0 AH
Days Below 5 AH: 4

May Stats
Monthly Total: 985.2 AH
Daily Average: 31.78 AH
Best Day: 57.1 AH
Worst Day: 7.2 AH
Days Below 5 AH: 0

These stats are for the solar panels only, I still don’t have any method of measuring the output of the wind generator (H80) over time.

     

Off-grid System Maintenance

I’m not sure why but some people seem to have it in their minds that living off-grid, generating your own electricity involves lots of work (though if tinkering is what you want it can, as a quick browse through the the archives of Homepower magazine will demonstrate). However for most people, myself included, the system takes care of itself quite well. So for the benefit of the curious I thought I’d detail the maintenance needs of the various parts of my system.

The Solar Panels
The panels themselves are solid state and require no maintenance. In the winter I prefer to brush off the snow, but that’s just because I don’t want to wait for the snow to melt off. If I’m up on the roof I usually do a quick inspection of the panels and racks just to make sure that nothing is loose or damaged in any way, and in the last year nothing has been.
Total Time: one hour every six months (if that)

The Wind Tower
Like the panels whenever I’m at the top of the hill I do a visual inspection of the tower, just to make sure nothing is obviously loose or noisy. Every two years the tower must be lowered to do an inspection of the generator itself, and lubricate/clean/tighten various parts.
Total Time: visual inspections / half day every other year

The Batteries
Once a week we try and make sure that the batteries get a full charge in them, this often means running the generator for a few hours. Once every month to three months (depending on the season) we do an equalize charge, which requires sun, wind, and the generator running all day. Every month I check the fluid levels of each cel, and top them up with distilled water if needed. Before and after an equalize charge I take readings of each cel with a hydrometer to measure the specific gravity of each cel, this is the most accurate method of determining stage-of-charge.
Total Time: half an hour every month

Electronics
I’m lumping the inverter, solar charge controller and wind charge controller into this group, and aside from monitoring (see below) there is no maintenance for any of this equipment, it’s all solid state.
Total Time: zero

Monitoring
Monitoring the system performance is important for many reasons: first it lets you know how your power generation and power consumption are comparing, which I think we can all agree is pretty vital, second by tracking base line numbers you’ll realize if something does go wrong. My biggest gripe with various aspects of the system is the lack of quality monitoring, especially where the wind generator is concerned. I keep a chart by the inverter and every night before I go to bed I write down how much the solar panels generated that day and cumulatively, the battery voltage, amp/hours away from full charge (which is an approximation), and details about whether the generator was run, if we achieved float, full charge, equalize, and if water levels were checked.
Total Time: two minutes each night

Gas Generator
Unfortunately this is still an important part of the system, and with months like November likely always will be. Aside from adding gas, I check the oil once a month, clean the air filter every other month, and just generally check it over whenever I gas it up.
Total Time: one hour every month

To sum up that comes out to about three hours every month, which is less time than I spend cutting the grass. Every couple of months I might have to spend an extra hour on some aspect of the system, and in fact most of the extras (like equalizing) are highly automated, start the generator at the beginning and stop it when the equalize is done.

For most people using a wind generator or solar panels in a grid inter-tie situation there is even less work to be done, since the vasy majority of my maintanence is the care and feeding of my batteries.

I have a well planned system installed by professionals (I recommend the fine folks at Generation Solar), if you’re a hard-core do-it-yourselfer your milage may vary, and if you go with some fly-by-night installers all bets are off. Remember when you’re talking to any kind of contractor ask lots of questions, if they can’t answer them in a way that you can understand that’s a bad sign. Ask for references, and CHECK THEM! Ask to see some systems they have installed, pay attention to the details, is the wiring neat and well routed? Does the system look like a pro job or some kid’s science fair project? How long have they been in business? How many systems have they installed? You might spend a bit extra but the results will be worth it.

     

Stats - December 2003 - February 2004

Things definitely improved as we progressed through the winter.

December Stats
Monthly Total: 607.1 AH
Daily Average: 19.5 AH
Best Day: 45.5 AH
Worst Day: .2 AH
Days Below 5 AH: 8

January Stats
Monthly Total: 654.1 AH
Daily Average: 21.1 AH
Best Day: 55.1 AH
Worst Day: 0 AH
Days Below 5 AH: 8

February Stats
Monthly Total: 868.8 AH
Daily Average: 31 AH
Best Day: 63.1 AH
Worst Day: 0 AH
Days Below 5 AH: 3

This doesn’t take into account the power from the wind generator. I still don’t have any method of measuring the output of the H80 over time. I can state that we have been generating much more power from the wind generator, we’ve had several days where I am certain that we made more than 100 AH from wind.

     

Positioning Solar Panels in Northern Climates

This isn’t a post about solar panel azimuth or anything so technical. It’s far more practical advice I’m offering today: if you live in an area that gets a great deal of snow (currently we have between 2 and 3 feet), and you are going to be putting your panels up on your roof, make sure that you have a easy, safe method of clearing snow off of them. Yes the snow will eventually melt off, but I hate losing a full day of sun waiting. Clearing the snow off our panels is a chore that I do not enjoy, climbing the ladder onto the very slippery steel roof and clearing the panels is bad enough, but getting back off the roof and onto the ladder is NOT FUN. The only consolation is that if I fall it will be into four foot deep drifts and onto Gator, who will be trying to catch the falling snow, and will instead get me.

If I were doing it again I would build in a dedicated rest for the top of the ladder that prevented it from sliding sideways. Then I would build a metal catwalk with some angle irons and metal mesh - neither of which is an expensive material. For the sake of a couple of hundred bucks I’d be able to walk around the panels in confidence.

Better yet, if your site allows it, mount the panels on the ground.

     

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The House in Pictures

I’ve put together an overview in pictures of the house from the day we broke ground (August 2002) to when we moved in (May 2003).


     

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Six Month Stats

Now that we’ve been in the house for six months I’ve compiled stats for what we’ve generated off of our solar panels since June of 2003. Because we reset the system when we swapped in the new battery in early June the stats for June start at the 11th.

I have no stats for the wind generator because we have no way to track its production over time right now. If I can find a method of storing data for the wind generator that isn’t expensive and that doesn’t consume electricity itself I’ll set it up, until then it’s all anecdotal. Most of the summer was pretty still and winds have been steadily increasing since late September/early October.

All readings are in amp/hours (AH). Our solar panels and battery bank are wired for 48 volts (V). To calculate Kilowatts (KW) multiply AH times voltage (V) which will give you kilowatt/hours (KWH) at 48V, divide by 2 for KWH at 110V.

Our solar collection system consists of 8 BP Solar 85 watt panels, which feed 48V through a Trace C40 into our battery bank. All of the stats are taken from the C40.

     

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Drywall Part One

Saturday. Beautiful day. Sunny, warm (-2C). The panels were pumping out 10 amps (which is about the max). We ran the generator all day to refresh the batteries. The timer seems to be working, Dad ran the generator on Monday, and it wasn’t run again until today. The batteries seemed to be just fine.

I got lucky again at Eurolite, somebody returned five of the lights we wanted to use in the kitchen, so they gave us a deal. Earlier we lucked out with the fans. We like Eurolite, they’re good people.

So today I hung the first kitchen light to see what they’ll look like. I’m going to Photoshop in all five at the proper heights, I might post the pic. We also took delivery of this really fantastic Italian florescent fixture, two 4’ skinny tubes and one hell of a reflector makes a bright bright light. Plus an electronic ballast for low noise. So I put that in the battery room and it really helps.

Mom continued her taping, she’ll be happy when that job’s done. Dad worked on the bathroom doors. And then, after lunch, we drywalled. Yessir, nothing says fun like drywallin’. We got one wall and the ceiling done, taping and mudding tomorrow. We’re thinking of doing the entire west wall in tongue and groove cedar. After we got home Dad and I spent a couple of hours planing and jointing some of our cedar. It looks like we’ve got enough for the west, north and south walls. “But Glen,” you say. “What will you do behind the shower?” Hey all of that boat building experience hasn’t gone to waste, we’re going to put a layer of fibreglass and epoxy over the wood in the shower stall.

This morning and this afternoon I took the dogs for a walk. Apparently all of the rain that we got in Toronto last week was snow up here. The snow is up to my knees in the bush. That’s a serious impediment to the dogs. They are exhausted.

Last, but absolutely not least, a big congratulations to Steven and Laurie who just gave birth to their first child, an (undoubtedly) beautiful baby girl named Malaika. Way to go guys!

I have no pictures of the baby, but I did take pictures at the house.