Tag: Solar System

Solar Power and Off Grid Operations

In my previous post, all major installations were completed. Since that time, the ESA inspection was completed and we validated our batteries so that we have confidence that they will last for more than a day in the worst case scenario (no sun). However at the time of this writing, we are still waiting for Alectra Utilities to switch out our old meter to a new one that is net-meter capable. Until this meter replacement occurs, every watt-hour (Wh) of energy we produce and send back to the grid, Alectra will charge us for it as if we are using that energy instead of producing it. Here is a summary of the timeline from panel installation:

Solar panels installation completed on April 8th;
ESA Inspection on April 12th;
New LiFePO4 batteries installed on April 18th;
From April 18th onwards, we tested the system through a series of scenarios;

Our Utilization Chart from Alectra Utilities (click to enlarge)

So prior to the ESA inspection on April 12th, we continue our on-peak time shifting. You can see that there has been very little on-peak usage (red indicator) before April 12th. Once the ESA inspection is completed, we turned on our solar panels for the first time.

The erratic “usage” indicated in the above chart after April 12th, is a direct result of excess solar energy being exported back to the grid. Since our net meter has yet to be installed, Alectra sees it as usage, and unfortunately I will have to pay for that generation, very ironic if you ask me.

Nevertheless, we gathered much data in the last couple of weeks. We tested the system for both on grid and off grid operations. We tested with washer and dryer loads. Today on a bright sunny day, I even tried our air conditioner when we are off grid. The air conditioner started without any issues and worked with just solar energy, impressive. I will try again at night when we only use the batteries.

Let us take a look at our energy generation data that we collected so far. The information here is a surprise to us in a good way. The best way to show this is to provide the data for our best day performance to date.

Our best performance day (April, 20th), 103.63 kWh generated

On April 20th we had a beautiful sunny day. We generated 103.63 kWh of electricity, since the house could not use it all, we fed most of it back to the grid. This is an excellent run and really show what the panels are capable of. For comparison, our average daily use is between 30 to 40 kWh. This means our solar generation ability on a sunny day can easily cover 2.5 to 3 days. For those Tesla drivers out there, we can generate enough power to fill your “tank”.

A rainy and cloudy morning and the sun came out at around 3pm.
Total generation: 32.53 kWh (not whole day)

Yesterday was a rainy and cloudy morning, and the power generation on average kept up with house load usage. We woke up with the batteries at about 50% charged and the system managed to gain around 10% of battery charge at 3pm. After 3pm, the sun started to come out and the batteries charged rapidly. It easily reached 87% state of charge, and I had to shut the solar generation down at around 5pm, otherwise the energy would have no place to go, which leads to another major dilemma for off grid operation.

During on grid operation, the grid can regulate and absorb the excess energy generated by our solar panels. This is a huge convenience, which until we have the net meter, we really cannot take advantage of.

During off grid operation, we must use all the energy generated. Our supply must match demand and vice versa. This is where the batteries come in. They help to buffer or store the excess, and supplement any shortages. However, when the batteries are full and our usage cannot keep up with the generation, then the best option is to shutdown the solar, and shift our energy consumption to the batteries. Using the batteries will create more “empty” capacity, which we can later use to store more sun energy. I assumed, incorrectly, that this power regulation will be handled by the Schneider inverters. This is not the case, at least not fully. I am not going to go into details of Frequency Shift Power Control and other inverter deficiencies here, but suffice it to say that they are really not that smart. We will have to investigate on a more flexible power regulation mechanism for off grid operations in the future.

In the meantime, I have developed something myself that will monitor battery usage and solar power generation, so that I can determine when to turn on the solar and when to turn it off. Note that this is only for off grid operations. Once we have the net-meter, we can go back to on grid operations, and the convenience of the grid can act as the main regulator of power.

However, this is excellent experience as it teaches us some of the off grid challenges. There is no substitute for living through the experiences.

We hope the net-meter will arrive soon. Until then, we will challenge ourselves to see how many days we can stay off grid! You can already see our progress on the 23rd and the 24th of this month from the above Alectra utilization chart.

Cheers! Until the next update.

Solar Panels on the Roof

On March 31st, I saw the following picture from my garage security camera:

It took several days to install the 56 335W panels from Canadian Solar. We just finished the installation yesterday and we are now awaiting for ESA inspection and commissioning the system.

The weather was borderline cooperative, being wet and fairly high wind situations (gusting near 50 to 100 km/h at times). However the installers from New Dawn Energy Solutions soldiered on and completed the installation yesterday.

Instead of me blabbing about how the install went, here is a short video on the near daily progress.

Near Daily Progress of Installation

The system is now ready to generate power as soon as ESA inspection is completed and our power meter is changed for net metering. Hopefully this will happen in the next week or so.

Residential Backup Battery Installed

In an earlier posting, I outlined how we initiated our solar panel project. Although the current weather condition prevents us from installing the solar panels at this point, we can install all of our required inverters and backup batteries.

On February the 22nd, we connected our Schneider Hybrid inverters to the grid, and on the 23rd, we connected the Pylontech LiFePO4 (LFP) batteries.

We configured the inverters so that the batteries will be discharged during the peak hours and charged during off-peak hours, effectively performing consumption time-shifting so that we can take advantage of the lower rates:

As you can see the savings are quite significant, more than 50%.

On February the 24th, was our first full day of usage when we tested our time-shifting configuration, and we found that it worked quite well. The battery capacity was enough to cover all of our on-peak hours usage save for the last remaining on-peak hour period.

Notice that we have more green in the off-peak hours because we are storing that capacity in the form of battery storage. I will play around with the configuration some more to see if I can shift the uncovered, on-peak hour to the mid-peak period, so that I have enough battery capacity left to cover all the on-peak periods.

I want to give a big shout out to New Dawn Energy Solutions. They have been very professional and really know their stuff. Any one thinking of installing a solar and/or a battery backup solution within the Greater Toronto Area, should seriously consider them. I highly recommend them and hope to do more business with them in the future.

Stay tune, and I will continue my progress here on the blog.

Residential Solar Project Initiated

This spring, I installed solar panels on our green house. This project gave me the experience and knowledge of what I wanted for our house. In August of this year, we finally took the plunge and initiated our solar project for our house.

After much research, I settled with the following three vendors:

They all had a web presence and I initiated contact either by phone or with their online registration. For all three, I provided my postal code, my utility bill or usage, and they were able to prepare a quote for me to review. My initial request was for a grid-tie hybrid solution consisting of: Solar panels, and batteries. Specifically, I wanted to perform a full backup of my house electrical demands in the case of power outages. I wanted to avoid a typical solar only, net-metering, grid-tie solution. I also did not want a partial backup solution where certain high inductive loads such as air conditioners and dryers will not be available.

All three vendors came back with a simple solar net metering solution, the one that I specifically said I did not want. New Dawn Energy Solutions was the only vendor that gave me multiple options, one of which was a partial backup solution, which did not meet my full house backup requirement. With this initial misunderstanding, I thought it would be best that I spent sometime detailing exactly what my requirements are. I proceeded to create a slide deck with this purpose.

Long story short, getting a common understanding of my requirements was still a challenge for the vendors with the exception of New Dawn Energy Solutions. I was able to directly contact the engineer who prepared and designed the solution. This was during the weekend, and we were able to quickly clarify what I wanted and what New Dawn Energy Solutions can provide.

I decided to select New Dawn Energy Solutions and proceeded with a contract with them. While we await for permits, New Dawn Energy Solutions also helped me to start my energy audit for the Canada Greener Home Grant Program. Under this program, we can potentially get up to $5000 CAD back. The first of two audits was already performed by EnerTest. The auditor was super friendly, detailed, informative, and efficient. I would recommend EnerTest if you are going after the same program.

The current solution look something like this, but it is subject to change after an on site engineering assessment.

As of this writing, the first energy audit is now completed. Now we will await for the engineering assessment and the required permits.

I am excited to generate clean energy and will no longer be guilty of enjoying the full capabilities of my air conditioner during the summer heat.

Green Sunroom Project

YouTube viewing has been one of our favourite pass times during the lock down nature of the Covid-19 pandemic. I personally have been watching quite a few channels on how to use LiPO4 cells to build rechargeable battery banks for solar applications, primarily for off grid purposes.

We have a sunroom in our back yard that we used during the summer to grow some vegetables. It has some electrical needs such as water pumps, a temperature sensor, and a fan. Currently there is an electrical socket, fed from the house, that we plug these devices into. We thought it would be a good project to try to get our sunroom off grid. This would be a good learning project.

The first task is to build a 12V LiFePO4 prismatic cells battery bank. I purchased 4 3.2V 100Ah battery cells from AliExpress. The cells came with bus bars so I did not have to purchase those. However, I did have to buy a battery management system (BMS) to balance and manage the charging and discharging of the battery cells. It was very tempting to buy a BMS from AliExpress, but I decided to be cautious and purchased one from a US vendor with the accompanying and preferred quality control. The company Overkill provides a 12V BMS specifically for four LiFePO4 battery cells in series.

It took a very long time for the batteries to arrive from China. I suppose the pandemic could be one of the many reasons for the delay. Once they arrived, I connected in parallel and proceeded to perform a top balance procedure with my voltage limiting desktop power supply. This step is required because each cell will have a different voltage potential from each other. We want all the cells to have the same voltage potential to maximize the capacity that we will get from the aggregated 12V battery bank.

Cells in parallel being topped balanced at 3.65V until zero current

To top balance all the cells, first I hook up the cells in parallel and charge them at a constant voltage of 3.65V. The charge will continue until my desktop power supply shows zero amp going into the battery. This process took a very long time, almost 2 days.

Once the cells are balanced, I reconfigured the cells in series and proceeded to hookup the BMS and the pure sine wave 600W inverter I purchased from Amazon. I had to buy 4 AWG wire, once again from Amazon, because the 10 AWG wire that I purchased earlier was not going to be enough if I want to discharge the battery at 600W which is going to result in more than 50A of current at 12V. I used the remaining 10 AWG wire for solar controller and panel hookups. I also got some XT90 connectors so that I can easily plug/unplug the solar charge controller, solar panels, and potentially plugin charger. I will talk about the solar side some more later on.

All wired up. The yellow XT90 connector is to either a solar charge controller or an external DC charger

So now that we have the guts of our 12V LiFePO4 battery pack, we need to find a suitable home for this thing. My wife had an extra plastic filing box hanging around which is perfect for this.

A filing box is perfect to fit everything

I needed to drill some holes to fit a 12V 120mm PC fan for ventilation, and a couple of 2″ grommets so that we can pass plugs and connectors through the box. The fan will be powered by the inverter.

At this point we have ourselves a 1200Wh portable super battery pack that can power up to 600W of electronics, which will be great for road trips. If you plug a 20W iPhone fast charger and charge your phone, it can continuously charge for 60 hours (2.5 days). That is a lot of phones. If your MacBook Air ran out of juice on the road, then this battery pack can power a 45W charger for your MacBook Air for more than a day, and also charge your computer fully. Quite a handy thing to have for emergencies.

Doubles as a 1200Wh portable battery bank

For the solar panels, I purchased two Xinpuguang 100 W flexible solar panels from Aliexpress. They were about $1 / Watt, a pretty good deal. I hook the two panels together in series and got a Victron BlueSolar MPPT 75/10 solar charger to manage the charging of the batteries. The charge controller can accept a maximum of 75V and outputs a maximum of 10A.

The charge controller will automatically adjust the amperage and voltage to the battery bank as required ensuring optimal charging scenario. During a sunny day, it will run the sunroom load from the panels and any remaining current will goto charge the battery. At night, the battery will run the sunroom.

Today, we installed the entire setup. The battery is placed inside the green house to give it some precipitation protection.

The panels are latched to the roof of the green house, one on each side.

The BMS unit has a bluetooth connection and an iOS App. I can use my iPhone when in bluetooth range of the battery to see if the battery is being charged or discharged.

I took the following screen shot of the app today at around 5pm EDT. You can see that there is no current going into the battery and no current going out of the battery. This means the sun is powerful enough to run all the pumps and other electrical appliances in the sunroom. Pretty cool!

It is still too early to tell yet whether there is enough sun power to charge the battery and run the electrical devices in the sunroom in a sustainable manner. My current suspicion is that the two panels are just enough even on a full, bright, sunny day and at peak hours, to power devices and also provide surplus current to charge the batteries.

Here is my overall connectivity diagram:

We will let the system run for about a week to see if this is sustainable during the summer months or not. If not, then I will have to create an automatic transfer switch so that we can intermittently recharge the batteries during the evening with an optional 480W DC charger, which I also got from Aliexpress. This charger can operate between 0-24V and 0-20A. To charge the battery bank, I have set it to a constant voltage of 14.0V and allow the output current to flow unrestricted. This should charge the battery fully in a little over 4 hours from scratch.

Overall, I learned a lot from this project and what a great way to spend the pandemic indoors. This could be a precursor to a DIY Tesla Powerwall Project. We’ll see.

Scaled Solar System

School started this month. To my delight, I found out that one of my sons is participating in a paperless curriculum. Their first exercise is to recreate a scaled version of our solar system using the available area of their classroom ceiling. When my son told me of this exercise, I immediately thought about whether a linear scale would give enough fidelity to the inner planets that can be visually perceived by the students.

Driven by my curiosity, let me try to calculate it here. From this article, we know that there are multiple definitions of the diameter of the solar system. We will take the smallest definition, that being defined by the outermost recognized planet, which is recognized today as being Neptune. Neptune’s orbit has a diameter of 9.09 billion km.

This number seems to be a very large number. Let’s work with a more convenient unit, called the astronomical unit (AU), which is equivalent to 149,598,000 km. One AU is equivalent to the average distance between the centre of the Earth and the centre of the Sun. Working with the AU unit, we can now say the diameter of the solar system is:

$\frac{\text{9,090,000,000 km}}{\text{149,598,000 km}} = 60.76 AU$

Next, we need to find out a scale to represent how many AU’s per meter. Assuming a typical classroom’s dimensions are 15 meters wide by 15 meters long, we can now calculate the scale with:

$\frac{\text{60.76 AU}}{\text{15 meters}} = 4.05 AU/m$

If the Sun is situated in the centre of the classroom, we now need to know the radial distance, the distance in meters from the Sun to a planet within our classroom solar system.

$\text{Let P} = \text{distance from Sun to Planet in AU}$

$\text{Let D} = \text{distance from Sun to Planet in meters}$

We can then get the distance in meters for the above planet with this:

$\frac{\text{P AU}}{\text{4.05 AU/m}} = \text{D m}$

Let’s do this for Earth, which is 1 AU from the Sun. Using the above formula, we can get how far our classroom Earth will be from the classroom Sun in meters.

$\frac{\text{1 AU}}{\text{4.05 AU/m}} = \text{0.247 m or 24.7 cm}$

I hope our classroom Sun, represented by a balloon, has a radius less than 24.7 cm!

You can obtain the rest of the planets distances in AU on this site. I took the opportunity to also convert them into classroom meters.

Planet	AU from Sun	meters from classroom Sun
Mercury	0.39	0.096
Venus	0.72	0.178
Earth	1.00	0.247
Mars	1.52	0.375
Jupiter	5.20	1.240
Saturn	9.54	2.356
Uranus	19.18	4.736
Neptune	30.06	7.422

I guess I satisfied my curiosity. It does seem possible to create a scaled model of the solar system for a 15m X 15m classroom, where the inner planets are still visible to the naked eye.

However, the size of the planets cannot follow the scale. I will let the reader figure out why.

I also took the opportunity to write a small helper App for you to calculate the scale and the distances. Click here.