Today is a good day. Alectra finally installed the net meter. From my previous post, I noted that without a net meter, any excess energy being sent back to the grid will be interpreted as usage. With the addition of the net meter, we can finally export our excess electricity from our solar panels without being charged for the generation. Instead, we can start earning and storing credits for the excess energy that we will supply to the grid.
Prior to the presence of the net meter, we gained plenty of experiences on going off grid. Effectively even on a cloudy day, we were able to generate enough energy for the house and charge our batteries to get us through the night. Below is a depiction of our energy utilization from Alectra.
Started to go off grid on April 23rd
The process of getting this net meter installed was not an easy feat! It took 22 days from the time of ESA inspection (April 12th) to Alectra installing the net meter. In summary, we played with the solar system to see what it can do for 11 days (April 12th to 22nd), while paying for the excess generation, and went off grid for the remaining 12 days (April 23rd to May 4th).
The small usages from the 23rd to the 30th that you see above were primarily charging our Toyota Prius Prime from the garage. That circuit is still grid tied and is independent of our Solar system. I cannot get an updated chart that contains data all the way up to today. Perhaps Alectra is doing something in the background in preparation for them to switch to net metering. In summary, we were pretty much off grid from April the 23rd to around 2pm today (May 4th). There was one exception, when we charged our backup batteries during off-peak hours from the grid on the evening of the 26th. We didn’t have to, but I was bit anxious with the battery at 50% whether it will last through the night and to the next evening, so this was more of an insurance. As we get more experience, we now have the confidence that even during cloudy / rainy days in the month of April, we should have no problem charging the batteries from solar that will last to the next night time operation.
Our old unidirectional meter
Our new bidirectional net meter
Once again, I have to thank New Dawn Energy Solutions for their correspondence and baby sitting the net meter installation process, as well as closing out the building permit from Richmond Hill. I am certain there was plenty of red tape that must be cut by them to get to where I am today, so kudos to them!
Today was also the day when we completed our second audit with Enertest. Once again Nick Crosby, A Certified Energy Advisor did a professional job. This audit is mandatory for the participation of the Canada Greener Homes Grant program.
If you are thinking of installing solar, New Dawn and Enertest are partners and experts in your endeavours.
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.
On March 31st, I saw the following picture from my garage security camera:
The Panels Have Arrived!
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.
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:
From Alectra Utilities
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.
As I indicated in a previous post, I wanted to upgrade my old USG firewall to the new UDM Pro. In that post, I have outlined my reasons, so I will not repeat them here.
I wanted to perform the upgrade with a minimum amount of downtime. With several household members who are online constantly for both school work as well as for entertainment, any perceived downtime will result in a typical earful, which I would rather avoid.
In preparation for the upgrade, I performed the required backups for both the Unifi Video and the Unifi Network Controller applications that are both previously running on my NAS server. I copy the backups to an old MacBook Air that I will use as my console to setup the UDM Pro. I wanted to make sure that I stop both the unifi and unifi-video services on my Ubuntu NAS. We do not want to risk some sort of conflicts when we plug in the UDM Pro.
I also configured the old USG LAN2 port so that it will provision a network that has a separate IP subnet different from all of my existing networks. In my case, it was 10.10.11.1. I did this so that I can connect the UDM Pro into the LAN2 port of the old USG, which mimics my Internet Service Provider (ISP). This way, while I configure and setup the UDM Pro, my existing home network can continue to function and provide the require services to my household.
Connections used for UDM Pro setup
The setup connection layout looks like the above diagram. After the UDM Pro booted up, I used Safari to point to 192.168.1.1, which hosted the UDM Pro’s web administration interface. Since I already had a Unifi account, I used that to login initially. Once logged in, I proceeded to upgrade both the Network and Protect applications on the device. The Network application was upgraded to 6.5.53, and the Protect application was upgraded to 1.20.0. I am not planning to use the Access and Talk applications, but upgraded those any ways in case of any outstanding security holes.
I then open the Network application and performed a restore from the backup that I previously copied on to the MacBook Air. This restore worked without a hitch. All of my configurations and network and WiFi settings were ported over. The UDM Pro also automatically created another user from my old restore, which I promptly switched over, and disabled the external access to the UDM Pro, call me paranoid. I did a restart of the device to make sure that it boots back up smoothly. Once I have confirmed that everything is still okay, then I proceeded to shutdown the UDM Pro.
Before I make the physical swap, replacing the USG with the UDM Pro, I ssh into each Unifi managed device, switches and access points to ensure that the inform URL is reachable. Once I was satisfied of this, I then proceeded with the swap. Now my network looks like this:
Post upgrade layout (click to enlarge)
My expectation was that once the UDM Pro boots up and the Network application comes online, all the Unifi networking devices will automatically be managed by the UDM Pro. The reality however was slightly different. On the plus side, the network is fully functional and the only down time was the time it took to perform the swap and the boot up process of the UDM Pro, no more than 5 minutes. However on the down side, when I inspected all the devices (not clients) within the Network application, only one of all the devices successfully registered with the new Network application. I was a bit puzzled and miffed.
After about an hour’s investigation, apparently some devices did not like the inform URL to be http://unifi:8080/inform. I specifically picked the hostname instead of the IP address because it was changing from my NAS server to the UDM Pro. Unfortunately for some unknown reason, only a single Unifi access point UAP-AC-Pro made the jump and was successfully adopted by the UDM Pro. All the other devices went into a state of a repeated adoption loop. Even rebooting the devices did not help.
To remedy the situation, I had to ssh into each of the remaining devices and manually performed the following command (twice):
set-inform http://192.168.168.1:8080/inform
I am uncertain why I had to do it twice, but the first time did not work with the Network application. Once all the devices were adopted, I then proceed to configure the Override Inform Host settings on the UDM Pro. See below:
Note that the above settings were only in the New UI and missing form the Class UI
I had to set the above and not the default, because the will ubnt did not work, perhaps this had something to do with my Pi-hole configuration. Also, although by this point all the devices were connected, there were two remaining access points complaining about a STUN issue. When I check their respective logs, the STUN URL was incorrect because it retained the old unifi hostname. It was at this point, I decided to let the Network controller to push out an IP address based inform URL for all the devices.
I perform another reboot of the UDM Pro just to make sure we have transition stability over a power outage, and everything seems to be running smoothly now.
The restore of my Unifi Video configuration with the new Unifi Protect application on the UDM Pro was way more smoother. I dear say flawless. However, there was a minor hiccup. I run Homebridge at home to connect my Unifi Protect G3 Flex cameras to my HomeKit environment. This relied on an RSTP stream that was previously supported by Unifi Video. However the new Protect application used RSTPS, which is an encrypted version of the stream. Long story short, I had to switch from the Camera FFmpeg to the Unifi Protect plugin. Not a big deal, but I was super glad that the Unifi Protect plugin existed for Homebridge.
Now our inside security footages are recorded (up to a month), and motion detection is a lot faster. The application to find and view the videos are now more convenient. On top of that, live previews are also available within my Home App on my iPhone, iPad, as well as the Apple TV.
A gallery view from my 4K TV using Apple TV and HomeKit
The outdoor footages are still using Kuna, but I plan to perform a future upgrade using Unifi G4 Bullet cameras for the outside as well.
The last configuration I did was finally turned on Unifi’s Threat Management. I set it to level 4 to begin with and we may adjust it in the future.
click to enlarge
Last and certainly not the least, my NAS server is now more of a NAS and less of a networking controller, since all networking related monitoring and control is now being performed by a dedicated UDM Pro device. The UDM Pro can also handle the threat management at my full ISP 1Gbps download speed.
I will continue to post my upgrades here. If anything else, keep my future self informed.
We are all in with Unbiquiti’s Unifi lined of networking products. To date with the exception of a few unmanaged switches, all of our home networking switches and Wi-Fi access points are Unifi products.
Current Network Layout (click above to enlarge)
At the heart of our network is our USG Firewall (USG 3P). We’ve been using the secured gateway since December of 2017. During the holiday break, I plan to replace it with the new Unifi Dream Machine Pro (UDM Pro). The main reasons are:
The current USG 3P is limited to 85 Mbps when threat detection is turned on;
Run Intrusion Prevention System (IPS) and Intrusion Detection System (IDS) with the UDM Pro at full IPS speeds which for me is at 1 Gbps download and 30 Mbps upload;
Upgrade my current Unifi Video solution to Unifi Protect, since Unifi Video is no longer supported and I have five Unifi G3 Flex cameras;
Will most likely replace my current Kuna solution with Unifi Protect external cameras, so it is totally private, and my security video solution is unified;
The ability to connect Unifi Protect with my other devices using Homebridge;
The device has a capacity of up to 3.5 Gbps so we are future proofed for faster ISP speeds;
Move the UniFi Network Controller software that is currently running on my NAS server to a dedicated piece of hardware, the UDM Pro;
During my research with the UDM Pro, there is a slight regression in functionality that I currently use in my home. I currently use a functionality called static host mapping that allows me to give my NAS server several different host names so that I can use those host names to route to different in-home services, that is hosted by Apache2 server on my NAS. For example, the host name media.home routes to my home Plex server, and books.home routes to my Calibre server. Long story short, I need to run my own Domain Name Service to get this functionality back.
I have deployed and configured a DNSmasq installation before, but when I was exploring ways to reconfigure (hack) UDM Pro’s DNSmasq implementation, I came to the realization that it is probably best to offload the DNS functionality from the UDM Pro and run a dedicated instance on my NAS server. This way the upgrade path of the UDM Pro by Ubiquity in the future is nice and clean, and I can fully configure my own DNS the way I needed it.
With further research, I came across an alternative to DNSmasq, and that is Pi-hole with unbound, a full recursive DNS resolver. With this combination, I can essentially maintain my own local DNS records, satisfying my static host mappings, and also have a more private Internet experience for my entire home network when domain names are resolved by the authorized party.
I chose the Alternative 1 installation methodology on my NAS, but with a twist. Since I already have Apache2 installed, after the installation, I purged lighttpd from the installation, which came with the Pi-hole installation process. I also added the following to my Apache 2 configuration:
For extra security, I also added an .htaccess file containing:
% cat /var/www/html/.htaccess
<RequireAny>
Require ip 192.168.167.0/24
Require ip 172.17.168.1/24
</RequireAny>
The above ensures that only local computers or VPN clients on my network can gain access to Pi-hole. I also had to enable the above .htaccess file by adding the following in the main Apache 2 configuration file (/etc/apache2/apache2.conf):
<Directory /var/www/html/>
AllowOverride All
</Directory>
After a quick restart, Pi-hole is installed and operational. With an afternoon of testing, I noticed that some Google based shopping links have been blocked. We cannot have that during the holiday season, so I had to white list the following sites for them to work:
Click above to enlarge
Configuring unbound was really easy, I just had to follow the instructions here.
Now that I have my own DNS server running, I am no longer using Cloudfare or Google’s domain services. This translates to a little more privacy. I can also track which domains are being blocked and which domains are being accessed when I visit sites. Since this solution is site wide within my house, no additional work is required on iPhones, iPads, and client computers.
With this prerequisite step completed, I am now all set to migrate to the UDM Pro.
I thought it would be a good idea for me to give a a small tutorial on basic home networking issues, which many may find useful when diagnosing connectivity issues.
A modern, typical home network may look something like this:
Typical Network (click to enlarge)
Most people in our neighbourhood will have a cable based Internet access.1 Internet comes through via the coaxial cable, like the traditional cable that you used for your cable TV. This cable is connected to a cable modem, which in our case is the Hitron CDA3-35. The cable modem then makes the Internet accessible via classic networking cables with RJ45 plugs. Think of the cable modem as your main door to the Internet and nothing else. Since this box is typically provided by your cable company, you should probably not trust it, so it is a main door without a lock.
Some cable modems also do Wi-Fi, like the new Rogers Ignite Hubs. For best performance and better security,2 I would recommend configuring the cable modem in bridge mode and not in gateway or router mode. This means that it should not be the box provisioning and managing your network, and it will have its Wi-Fi functionality turned off. This also avoids double NAT-ing, something to be avoided in your home, in my opinion.3
You should invest in your own Wi-Fi access by purchasing something like the TP-Link AX1800 WiFi Router.4 This box provisions your residential network and your local Wi-Fi. You can purchase more advance / expensive Wi-Fi solutions here depending on the size and complexity of your residential layout.
If you have more than one Wi-Fi access point, I would recommend that they all have the same SSID but on different Wi-Fi channels. This will make it convenient and optimal for your Wi-Fi devices. Also keep in mind that some old / cheap IoT devices only like the 2.4GHz band. If you are in that situation, then you should create a specific 2.4GHz network with a different SSID.
If you want to try out VOIP (Voice-Over IP), you may also connect a VOIP Adapter. In our example, we have the Linksys PAP2T box. I am not going to go into details of how to acquire VOIP, or set it up, but this box effectively converts Internet traffic into voice traffic. Traditional landline phones can be linked up to the VOIP adapter using normal phone cables.
Okay, now that we have the different parts of the network defined, let us present a basic diagnostic workflow.
Basic Diagnostic Workflow
I hope the above introduction to the different parts of your home network and a workflow that you can follow will assist you in resolving some common connectivity issues in your home.
I recently upgraded all my WiFi access points to the Unifi UAP-U6-LR and UAP-U6-Lite. This will elevate my home to Wi-Fi 6 capable.
This was extremely exciting as my 802.11ax capable devices can now get between 100Mbps to 400Mbps depending on where we are in the house. It seems even the 802.11ac devices got about a 30% speed bump.
As a result of this upgrade, two UAP-AC-M mesh and one UAP-AC-Pro access points were retired from my house. I don’t recommend buying these devices any more since the Wi-Fi 6 devices from Ubiquiti are way more capable with higher performance and increase range than their 802.11ac access points.
However, the honeymoon period did not last long. After about a week, HomeKit devices started to show the dreaded “No Response” labels. Specifically, I had connectivity problems with Leviton Smart Decora Dimmers. In the past, all I had to do was recycle the HomeKit device and it was all good. Another episode of HomeKit and Leviton dimmer switch nightmare was experienced and documented by my previous blog post.
In this particular instance, the Leviton dimmers were able to join the Wi-Fi network and I can validate that with the Unifi Controller software. However, our HomeKit App was not able to connect to the dimmer switches. It took me sometime to figure out that the dimmers were unreachable by other Wi-Fi clients, but was reachable by computers that were physically wired to our network.
I found out which access point the dimmer switches were connected to and ssh into the access point to see if I can ping those devices, and sure enough they were unreachable. Below is a screen capture of the ARP listing from the access point.
Normal ARP listing from the Wi-Fi Access Point
When the dimmers were unreachable, the HW address was set to 00:00:00:00:00:00. After rebooting the culprit access point, I was able to access the offline dimmer switches again from the HomeKit App.
In summary, when HomeKit devices are offline with the dreaded “No Response” labels, here are the following things to try:
Ensure that local DNS is working properly and caches are emptied so that the latest data are available;
Ensure the device itself has acquired a valid IP address that is from your network;
Ensure that the device is reachable from the HomeKit App, typically from your iPhone or iPad;
Back trace the physical upstream networking equipment that is connected to your HomeKit device such as switches and access points and see which requires rebooting;
Apple could improve the HomeKit experience by allowing users to perform a full backup of the HomeKit configuration and reset the Home and perform a restore. Unfortunately, the closest thing that I found was from the Home+ App, but they do not restore device connectivity just their configurations.
When HomeKit works, you are literally like god, able to command light and switches with your voice in your home. When it does not work, it is extremely difficult to debug, due to a lack of diagnostics and logging.
After this update, my current networking layout now looks like this:
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.
Our Solar Setup
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.
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
Custom grommets and added a PC fan
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.
