A Walk through our PV System

Today's blog will not be featuring the usual excellent writing, great photos and interesting topics that you are used to since Rob is providing the content. Time to set the bar a little lower.  My topic is one that I know you will love - how our off-grid system works! Alison assures me that everyone  wants to know all about this... well, some people may want to know...OK... for sure her brother Mike will be vaguely interested! An off-grid system is difficult to describe without resorting to at least a few technical terms ("arc fault circuit protection" comes to mind) so don't worry if you doze off occasionally…..zzzzzz

An off-grid system is simply one that generates and stores all of it's own electricity - there is no normal electrical connection. For those who don't want to read the whole post, here is a summary of the vital information:

Do they save money? - "No"

Are they expensive? - "Yes"

Are they easy to install? - "No"

So, now that we have that cleared up, it becomes apparent that there are only two reasons that one would install an off-grid system: 

1. you live a gazillion miles from available power and have no other option 

2. you are seriously deranged and simply want to live the off-grid lifestyle. 

Let's just say that we do not live a gazillion miles from available power so draw your own conclusions.

Before starting, a brief digression on electrical inspections. Code requirements for PV systems are a fast moving target. After completely installing the system it failed inspection due to not having arc fault circuit protection (there's that term). This is actually the first inspection of any type that I have ever failed. The requirement has been in the code book since 2012 but was not enforced because at the time of purchase the necessary equipment wasn't available for off grid systems. Unfortunately, it took a year and a half for me to get the system completely installed and by then the inspector had started enforcing the rule. Timing is everything! I had to remove and reinstall a bunch of stuff and I then had to rewire the system a third time because the wiring diagram provided by the manufacturer was not the correct one for my system. Like you,  I am starting to really dislike "arc fault circuit protection".

So here we go.

The solar panels:

Our system uses 24 roof mounted solar panels (the array). In full sun, each panel produces about 255 watts of power at 35V so the array can produce a total of about 6.2 kW of power.  Panels can be wired in series to increase the voltage available or in parallel to increase the power (and usually both configurations are used in the system design). For voltage, you need to have enough to charge the batteries but not enough to damage the charge controller. Our panels are thus wired as 3 panels in series to produce 107 Volts (these are called a "string") and the resulting  8 strings are then connected together in parallel (in two sets of 4 strings, one set for each of the two charge controllers) to maximize power. One counter-intuitive complicating factor is that panels actually produce higher voltages as the temperature goes down, so the whole system has to be designed using a winter design temperature of -40 degrees (which is the lowest temperature recorded in this area. (I know, I know...why would anyone want to live here?)

An aside: Mounting the panels to a metal roof was supposed to be easy - they make clips that simply attach to the ribs on the roof, the rails then attach to the clips and the panels attach to the rails. Unfortunately, when I tested the clips they ripped the roofing apart before they were even close to the design uplift load. I then had to find a different attachment method that could handle the load and that didn't cause leaks in the roof.

Going through the roof:

Each string terminates with a single pair of wires (positive and negative)and these are routed into rooftop transition boxes at the top of the array (two boxes are required because of the number of strings installed). The only purpose of the box is to transition to less expensive wire and feed it through the roof with a waterproof seal. One of the difficulties in installing the panels was keeping track of the 18 different wires, so all wires were labelled at both ends before they were installed and colour coding was used to ensure that polarity is not accidentally switched.  I also used a voltmeter to confirm correct installation.

An aside: when I later had to rewire the system there was no longer any reason to use a transition box because the combiner was now just inside the roof and the wires were only 2 ft long. I had to rip out and replace all of the wiring that ran to the battery room and I could have spent the money much more wisely on a ton of beer!  (Alison frowns...)

Into the Combiners:

I will not bore you with the details of the combiner that I had to rip out, but let me say that it was inexpensive, easy to install and tidy. The replacement arc fault/rapid shutdown combiner boxes were expensive and a pain to install - but on the bright side, still pretty tidy. They are shown above - located just inside the roof of my shop.

As mentioned, there are 8 strings of panels used in our design. A single combiner can only handle a maximum of 6 strings thus there are 2 combiners - 4 strings are connected to each one.  As the name implies, each combiner merges the 8 wires from the panels into a single pair of much heavier wires and these then run through the gray tray underneath the combiners to the conduit on the lower left that connects to each of the two charge controllers (in other words, half of the panels will connect to one charge controller and half of the panels connect to the other). The combiners  also provide fusing and arc fault detection to protect against overload if a problem occurs with the rooftop circuits. Finally, there is also a box at ground level on the outside of the shop which allows switching the panels off in case of an emergency (it disconnects the rooftop panels and remotely trips another set of breakers to disconnect the charge controllers).

An aside: safety is a major consideration with these installations because if there is sun, there is power. You can't actually turn the panels or the batteries off; you can only disconnect them. Since the voltages are lethal, you really need to pay attention and be sure that everything is disconnected before working on the system!

And then into the charge controllers:

From the combiner, the wires run to the two charge controllers and these units control how much of the power from the panels is used to charge the batteries. The charge controllers use MPPT algorithms (Maximum Power Point Tracking) to maximize the power coming from the panels. Batteries are charged using a three stage program that applies different voltages and currents according to the state of charge of the battery. Since batteries can be damaged by either overcharging or under-charging, the programming has to be set carefully and then modified according to the age of the batteries. Once the batteries are fully charged the charge controller goes into a maintenance mode and power from the panels is basically not used. If you look at the display in the photo it reads that the charge controller is "sleeping". How cute is that! 

If you use power when there is lots available (a bright sunny day), then you basically get it for free and the batteries remain charged. If you use power at night, then the batteries gradually discharge and on the next sunny day they just charge up again. Off-grid systems are normally designed to operate for about 3 days without sun - after that the available battery power is depleted to 50%. Battery life drops dramatically if they are routinely discharged to more than 50% so if the sun doesn't appear in a timely manner, a generator must be run to recharge the batteries. You quickly learn to conserve power when it is not sunny!

An aside: These are pretty cool retro looking charge controllers eh! The two main manufacturers for off grid charge controllers are Outback and Midnite, and both units look like they were removed from an old juke box. It works out that they were designed by the same person and my guess is that he (like myself) is a retired hippie. (Alison: a what hippie ????)

Batteries are next:

Batteries are the black magic of PV systems - they are expensive and depending on the technology can be finicky, require a lot of maintenance and TLC and are very easy to destroy. And did I mention expensive? The batteries are used to store the electrical energy generated by the panels so that there is power without sunlight.  Ours are a flooded lead acid type and they are contained in a battery box to make sure that nobody can play with them and, for example, accidentally short the terminals which creates a rather spectacular but short lived pyrotechnical event. They also contain acid which is best avoided and when the batteries charge they evolve hydrogen gas, which is explosive. All in all, these are well suited to our keen sense of adventure. On the plus side, the battery box also contains the hydrogen gas and it is then vented to the outside using a vent fan (the fan is programmed to switch on during the charge cycle that produces most of the hydrogen).  

Our system uses 12 batteries at 12V each and we need 48V. To accomplish this, four batteries are wired in series and as with the solar panels, these are also called strings (which can be confusing). Each of the 3 battery strings is then connected in parallel to a positive and negative bus bar (simply a point of connection that can handle a lot of power). The purpose of all of this is to increase the power available from the battery bank while maintaining a usable voltage. To ensure that all of the batteries charge at the same rate, all corresponding wires in each string have to be exactly the same length and since the wires have to handle a lot of power they end up being quite thick (the final wire is about 1/2 inch in diameter)

For safety, the circuits are fused before connecting to the bus bars and then two very heavy wires (a red and a blue wire on the bottom right) are run from the bus bars to the Load Center . This then provides the path for charging and discharging the batteries.

The load center:

The load center is where all of the components connect together and it is pretty much a rats nest of wiring due to a rather poor layout by the manufacturer. It directs the power into and out of the batteries and to and from the inverter. It also allows a generator to be hooked up and controlled and allows connection to the normal power grid (if it is available). Finally, there are circuit breakers to protect each circuit and there are connections to output the AC power to the house.  Everything is run in conduit to protect the wires from physical damage.

The Inverter

The purpose of the inverter is to convert the 48 volt DC power from the batteries into useable AC power. The system we use produces power that is exactly the same as a normal house (120/240V split phase). To do this, there are actually 2 inverters inside the box, each producing 120 V but out of phase with each other. The AC power from the inverter is fed back to the load center, then through a main circuit breaker and on to the load panel in the house (3 wires, 2 hot and one neutral).  From there it is a normal house system but it is of course limited by the available power in the batteries and the size of the inverter (we can pretty much run anything, but we can't necessarily run everything all at once).

System Control:

There are multiple systems that need to be programmed, controlled and tracked and this is accomplished using the panel shown above.  All of the parameters can also be monitored using a computer connection or they can be completely controlled and programmed over the Internet.

And here is the tidier version 

After the system is completed and the panels installed.

Does it actually work?

Happily, yes - so far anyway. The background draw of power from the system amounts to about 70 watts (which powers the system itself and the rapid shutdown). All of our lighting is LED so even with a number of lights on the draw is only an additional 35 watts. Continuous loads are the ones to watch out for and the only large, steady load in our house is the refrigerator (which has not been moved in yet). I can work in my woodworking shop all day, start any of my stationary tools (some have 5 hp motors) and run a dust collector, air cleaner and woodworking machine all at the same time.  If it is sunny, the batteries will still be at 100% at the end of the day. The real test will come during the darkest months when the amount of sunlight is limited (December-January) - so I will post in February and let you know how it went.

That's it (and I'm sure it's much more than you ever wanted to know). For me, this was really a fun project!
(Note by Editor: Fun ? Hmmmm.... well it had it's moments.  Am now throwing out electric blow dryer, and taking "clothes dryer" off of the "to buy" list.... ) 

Summer 2017: In some ways, NOT "The Best Summer Ever" !

Sometimes before I write a new blog post, I look back through older posts to see what we were doing at this point in time in previous years.  Well, last year's post was titled "Best Summer Ever" and we had to laugh, as that certainly does not describe this year; at least as far as the weather was concerned.  We broke an all time record for rainfall in July, and I believe, in May as well. We had a lot of cool days that were well below the normal "highs" for this time of year, and few if any of the normal warm summer evenings too. We often found ourselves sitting in the cabin on a cool evening, in long sleeve shirts, jeans and hoodies, closing up the windows, and watching the outside temperature plummet.

On the plus side, when I look back at the last blog posting in May, at least it did not snow in June or July!
And the rising waters we had in May did eventually recede. As of mid August though, the river was still much higher and faster than usual, and we were unable to venture in at all.  Not that we'd wanted to do that very often, as we hadn't really felt any need to "cool off" !

Back at the end of May we peered into the overflowing creek waters at what we first thought were cute little tadpoles. But after a bit of research, we discovered they were in fact, mosquito larvae!

We had a feeling it was going to be a "buggy" summer. And it was, with the black flies, mosquitoes, deer flies and "no-see-ums" all out in pretty good force at times. Despite the bugs, and because of the cooler temperatures, we made the decision to take advantage of the weather and get at our tandem load of fire wood, hoping we could split most of it, and get it drying ready for winter. Rob began by chain sawing it all into reasonable lengths, that would fit our wood stoves.

Then together, if it wasn't raining, we would spend some time splitting and stacking.  I had thought I could do the splitting on my own, but it turned out that I couldn't manage to lift most of the big rounds of wood onto the splitter. We got pretty good at working together; Rob would lift the rounds of wood up, I would split and he would stack.  We had to wear our "bug nets', and made sure we were pretty much covered up with hats, long sleeve shirts, gloves, and long pants to keep the bugs at bay, and of course wore our steel toed boots for safety reasons. It took us the better part of a day to do about 5 cords.  There is about 7 cords finished in the photo below.

It got a little warm to be wearing so much clothing on the sunny days, and eventually, when it got too warm - we quit. But not until we had almost 16 cords split and stacked! We decided that was more than enough for the upcoming winter. The rest will be split in the fall when it's cooler again (and hopefully not as "buggy"). There is probably another 4-5 cords left to split.  At the end of the day, we sat down and admired our hard work!

This summer we seemed to spend a lot of time jumping around from job to job.  Sometimes it's just really hard to find what we need locally, and we often have to shop around several different places until we can find what we need.  As I have a job that is a half hour drive away, and we only have one vehicle, it takes a little more planning sometimes too, to do the needed pick-ups! So often we will just leave a job and move on to another one, until we can get what we need to finish the original task.

One of the bigger jobs was to finish the necessary changes to the solar powered system, (which Rob promises to write about in a separate blog soon!).  But spoiler alert - we passed our final inspection!

We also kept working on installing our pine ceilings and finished the last sections that needed to be done. The photo below is looking up at the ceiling of our bedroom.  We still have to find some light fixtures for where those bare bulbs are installed, but the LED bulbs will do for now. It's going to be a lovely space....

In mid June we were hit by a powerful storm that knocked out power lines, and phone lines, snapped a nearby  hydro pole and felled a number of our trees. Although we had full power in the new house, we still didn't have any access to running water, so it wasn't a lot of use to us. Luckily we have a generator and an emergency reserve of bottled water, so here in the cabin Rob was quick to hook up a lamp for light, and made sure we at least had coffee at the start of the day! It's all about priorities.

As soon as the storm was over we went out to look for damage, and checked on our neighbours. Some of the trees looked like they had just been twisted off like a twist-top bottle by the winds.  Later on we discovered more trees came down in another nearby area of the forest. 

Kudos to Ontario Hydro who got a new pole in, and had us all up and running in 24 hours.  Our phone line was temporarily repaired within about 48 hours, and a couple of weeks later the lines themselves were permanently restrung. The oddest thing is that right after the storm, the mosquitoes were frantic, and the air was thick with them. We could barely step out of the truck to look for storm damage before they descended on us! A short time later the mosquito numbers were back to normal and we were able to get a better look at things. It's not the first time we've noticed an increase in bug activity just shortly before or after a storm.

Towards the end of June, Rob had the treat of watching a large snapping turtle (hopefully) laying eggs near the new house.

She did an interesting "left rear foot" then  "right rear foot" shuffle, which seems to indicate there were turtle eggs being deposited, and covered up.  Rob watched from the window as he didn't want to disturb her.

And then she sauntered off.

Earlier in the spring we had picked up a second hand door (second hand - but never used!).  A phoebe had made a nest just to the left of the entrance, and we decided to wait on installing the door, so that we wouldn't disturb her. As soon as the babies had hatched and left the nest, we were able to install it as our "front" door. I'm not sure we will use this door very much as I think the mudroom door will be the preferred entrance, but I guess we will see.

Despite our feeling that summer would never arrive, Jet decided summer had indeed arrived and began to "blow his coat".  No amount of brushing will keep up with it!  He always looks several pounds thinner when his summer coat comes in. Sometimes we find that the birds have used his hair for nests, so it's nice to see it put to a good use.

He's had some recurring yeast infections in his ears, so the vet suggested it may be due to an allergy to something in his diet. He's had to give up all his yummy treats (bananas, cream cheese, peanut butter, bites of apple and yes - corn chips - don't ask...) and is on a new dog food.  The animal hospital gave him a new Kong toy to make up for having to give up all his favourite foods.  It's called a Genius - but we thought it would be fun to call it a Jean Genie.  (Yes - after the David Bowie tune!) Jet quickly learned it's name, and will go get it whenever we ask him where Jean Genie is, but then we can't stop singing that song....perhaps a bit of a mistake.

We decided to get back to working on finishing the house ceilings, and installed all the drywall into the dining room and kitchen area. (It wasn't as easy as it sounds). It was a good decision we think, to do these ceilings in drywall rather than pine like the rest of the house. Here's hoping we pick the right paint colour though, as I doubt we will want to repaint it any time soon after we get it done. It's going to be a bit of a finicky job.

The house is starting to look like a real house!

Next, it was time to get some running water into the house.  The well itself was dug before we even poured the concrete slabs, four years ago.  Now we had to dig out around the well, in preparation for the final well hookup.

On the day of my birthday, just as Rob and I were heading out to spend the day together, the "well guy" called to say it was a good day to get our final well installation done as there was no forecast for rain that day.  So we immediately switched gears, and said "o.k".  As soon as it was done we headed out to at least five different stores in two different towns, to look for the needed parts to complete the water hookup. Never let it be said my birthdays are boring !!

We still need to have the water tested, but we can at least now use it to flush our temporary toilet. (We will install our new permanent toilets once the concrete floors are finished, and the walls have been painted. ) Next time we have a power outage at the cabin, we won't have to worry about not having a working toilet! (No power in the cabin = no running water either).

We installed our pressure tank and tankless water heater. And yes - Rob does know what he's doing with that extra pipe in his hand...  Our hot water will be heated by propane for the moment at least.  In the summer it would be nice to use solar power, so we may switch over to an electric powered heater in the summer months when we produce excess power anyway.   We know we will be working out a few things once we actually move in, and are able to judge what is working for us, and what isn't.

Next on the list was getting the propane lines run over to the kitchen as our kitchen stove runs on propane. Again, we think that in the summer months we will try to use an electric induction stove for some tasks. Most of the off grid folks around here have a variety of seasonal options that they use; trying to make use of the excess solar power in the summer months, and working around the possible lack of solar power in the height of the winter.

Mid July approached and we still were still waiting for "summer" weather. Every day we would see the dark clouds roll in.  We had numerous thunderstorms and more power outages, and it became routine to fill up carafes with hot water for hand washing, and jugs of water for filling pet water bowls whenever there was a mention of thunderstorms, knowing we would likely lose power again.  Once we get the water tested at the new house, we will be away to trot over there for our water, and can of course heat water there whenever we need to.

On the plus side, the heavy rains have made the vegetation look lush all summer. The sumacs are stunning.

But surprisingly, even my indoor potted plants are sprouting mushrooms....

We don't really know if the higher levels of water were good or bad for our "wetland" area, but it did seem to attract the Great Blue Heron there this summer, and Rob kept seeing another heron like bird here and there. At first we assumed it was a Green Heron, but late one afternoon this lovely bird stepped out into the brush in front of the new house.  We have seen these before in the wetland area we tried to save when we lived in Navan (sadly we did not succeed).  So it was with great delight that we had the opportunity to see this American Bittern, in a classic "freeze - I am not here pose"  AND get a photo!  When it walked back into the wetland I started to cry.  I guess I really never thought I'd see one again, and certainly not in our own sweet little area next to the house.

I guess it's been a summer of wildlife sightings. Earlier in June Rob and Jet were out for a morning walk when Rob spotted a rather large bear on our driveway, just a short distance away.  He carefully diverted Jet's attention and backed away...  We called our neighbours just to let them know one was headed their way, but didn't see any sign of it again. I must say though that for the next few days when I traipsed around the property by myself I had the habit of clicking my fingers, scuffing my feet, and loudly singing a little made up mantra type song... "trying to make some noise... and trying not to look delicious " !

Because of the bear we also set up a trail camera, and although no bear showed up on the camera, we were soon watching videos and photos of a family of foxes that moved in near one of our culverts.  I guess there was a reason for Jet sticking his nose in there!  It was fun to watch the young one's antics, especially as they tussled around in the early hours of the morning. Not quite as much fun to see what their Mom or Dad brought them to eat! The quality of the trail camera isn't great, but it allows us to see what's out there, especially at night.

And of course, you never know what you will see; we only just recently went through the videos and photos on the camera, and noticed a coyote was standing in front of it one afternoon!

One of the next tasks we tackled was to build the interior window frames for the house. Despite having our own collection of maple, ash and cherry, we still needed to purchase a bit more wood in order to complete the frames.  The windows in the living room are rather large, and although we had a lot of shorter pieces, we didn't have enough long pieces to allow us to do a straight run of the horizontal frame pieces, and of course, seams are out of the question ....

Rob sure looks happy working in his new workshop, although it still needs to be set up properly.

We chose to put the first frame in the mudroom, sort of a test piece I guess.  It is made of ash wood, which we quite liked.  It was great to see the first window frame in! We have designed them with a slightly different method, which I am sure Rob will explain later.  

I have been really fortunate to have the opportunity the last few months of entering a "Photo Challenge" which was kindly offered by my super sis's brother in South Africa.  Every week he issues a different "challenge" theme, and we have a week to do it. He then offers a very constructive (and kind) critique of our photo.  I have learned so much already, and look forward every week to the new challenge.  And it is a challenge - not only to meet the criteria, but to do my best to figure out how to make my camera see what I see.  Sometimes it's just a challenge to find the time, but as I am always in my "happy place" when I am out and about with my camera, it is easier to make the time.  So here's a big shout out to PhotoCoach for donating so much time to the Challenge, and if you are on Facebook, please check PhotoCoach out (and if you are in South Africa make sure you sign up for their awesome courses!)

One example of a recent attempt at a "photo shoot" was the "Frame Challenge", and as Rob and I had decided to spend the day together on a little trip around some of our favourite local areas, I brought my camera along.  Rob and I took a lovely trip around Round Lake, and stopped in Killaloe where I tried a covered bridge photo. Rob of course, was checking out the timber construction.

The view from inside the bridge:

Then it was off through the beautiful area around Brudenell, where I tried some more photos, down past  Lake Clear, and back home and over to one of the Mennonite farms where I tried my hand at capturing some of their recently hand stooked crops (all cut using horse power!).

We then checked out the Bonnechere Caves area, where we knew there was a trail to a cool natural rock archway that might work:

And then off to Balaclava to take some photos of the old abandoned sawmill there:

This was not the photograph that I chose either, but it sure is an awesome building. There is even a Great Blue Heron in the far left corner, fishing for some food in the river!

My final choice for the challenge photo is below.  It is of one of the windows in the mill, and kudos to Rob for spotting the amazing light in the broken window. It sure was fun driving around together and looking for inspiration for this challenge. (And once submitted I did learn how I could crop this a bit differently, and things to try next time!)

So, as you can see, we do sometimes leave the property and aren't always working on the new house! And I should add that we had the treat of some visits from good friends this summer, and did manage to attend a small family reunion as well.  It's easy sometimes to just want to hang out at the river, and in the forest, but we do try to keep up somewhat with our social skills!

Mid August, the river finally began to drop to more normal levels, and became more like the river we know in the summer. However, the high waters have changed the look of the shoreline, and moved rocks and spits of land, and deposited a stunning amount of lumber (presumably from people's docks up river) along the shores.  We've had some fun looking at some new fossils, and admiring the variety of rock colours.

I haven't yet put my nice benches back in the river as the levels are still fluctuating.  It's hard to believe but last year one of the benches sat where there are now all those rocks!

While we have been waiting and waiting for summer, it has become apparent that the season is on the wane, and not likely to arrive now.  Jobs that we lined up for fall, are suddenly looming closer! In no time we will be back to splitting wood I'm sure.

In the meantime we switched jobs (again!) when we realized we should get the last of the concrete poured while the weather was decent.  We needed concrete at the "front" door and the workshop door. We would have liked to have had some at the mudroom door, but the cost of pouring that much concrete was clearly too much.  We have interlock that we brought from our old house, so will probably use it there instead.

Rob chose the brief few days of warm humid weather to build the concrete forms, line them with foam slabs, shovelled in some stone, and installed the wire mesh.  Luckily some of that work was done in the shade!

Once the concrete is poured, we can put in the final timber frame structure at the front door, as that is a temporary brace and post, as well as finish up the area around the workshop door.

Sometimes when I write a blog posting it seems to jump around a lot, but it does sort of follow what has gone on here in the last two months or more.  As I finish up writing this, Rob has headed over to complete the work on the concrete forms, and I am sitting on the porch, enjoying for perhaps the first time in months, a warm sunny day.  The river has dropped and yesterday for the first time all summer we ventured in.  It was lovely! With cooler temperatures returning this week, I will probably see if I can entice Rob to take a few minutes and go cool off in the river again this afternoon.  Later this evening I am sure we will sit by the river and enjoy the warm evening breeze, and watch as the sun goes down.   It feels like we waited all summer for summer to arrive, and we will make the most of it today.