Fixing broken solar panel glass with a silicone encapsulant

Before and After

Fixing broken solar panel glass with a silicone encapsulant

I had a new solar panel propped up against a tree and it got knocked down by the wind and shattered (PSA, don’t do this).  The panel was still giving good current, however with the broken glass water would have quickly worked its way in and started corroding the components.  Rather than replace the panel I decided to make an effort to repair it (the warranty was voided anyway).

Broken solar panel
Broken solar panel – what have I done?

After giving it some thought I settled on a clear Silicone Encapsulant from Quantum Silicones called QSil 216.  This is a liquid silicone that cures into a solid flexible rubber-like material which protects electronics from moisture and vibrations.  It has a low viscosity and works its way around components as it cures sealing everything together.

QSil 216
QSil 216, ready for mixing

In the video you can see how I used a piece of wood to apply the product.  I had a comment that this may scratch the solar cells, however the glass was still mostly intact and covering the cells so the wood never touched them.  Here is what it looked like after I finished:

Repair job finished
Repair job finished

Temperature and Humidity during the cure process

The data sheet for this says it’s supposed to cure in 4 hours at room temperature, what I found is that it took MUCH longer.  I had it curing for a total of over 36 hours between 65 and 80 degrees Fahrenheit (that’s 18 to 27 for those of you in the rest of the world) and about 35% relative humidity.  Thanks to one of my sensor projects I have a log of the temperature and humidity in my garage over time so I was able to produce a report during the duration of the curing process:

Temperature and Humidity during the cure time
Temperature and Humidity during the curing process

It cures clear, and in the video above you can see it’s highly flexible.  Here is a close-up of the cured product that remained in my mixing cup when I was done:

Clear Stuff
Clear stuff

As far as I can tell it’s working fine after the repair.  However it’s October, I have it mounted in a area that gets a fair amount of shade, and I don’t have any identical OEM panels I can test against so I don’t know for sure how we’ll it’s doing as compared to when it was new.

If anyone has a good suggestion for how I might test the output of this panel as compared to original specifications I’d love to hear your ideas.  Please post in the comments!

Hope this helps if you find yourself in a similar situation.


Technology, science, building things and experiencing the world. What more could anyone ask for?

Environmental monitoring on the cheap with the ESP8266 (temperature, humidity, etc.)

Environmental Monitoring Dashboard

Curious about logging temperature, humidity, etc. or the ESP8266 microcontroller platform?  Looking to come up with your own environmental monitoring platform?  In this article I share some of the fun projects I’ve created to do just this.  Best of all it’s cheap and you can do this at your home/location without deep development experience (and I share code you can re-use to get started).

I’ve been meaning to setup some true DIY home IoT (Internet of Things) projects for a while now (read years). This summer during vacation I made a bit of time to try out the ESP8266 microcontroller platform.

The neat thing about the ESP8266 platform is that it has a native WiFi chipset, and as of about 18 months ago is supported by the Arduino IDE. All this makes programming and connectivity very simple.  They’re also available for only a few dollars each, which is a big plus as this is really just a tinkering project.  Over this last summer I ended up purchasing a total of 12 of these (plus an Arduino Uno R3 and several Raspberry Pis – but those are subject for future articles)

Some information on the platform itself.  I’ve tried a few different models and (for now) have mostly standardized on the NodeMCU v.2 as a development board, you can get them on Amazon here (2 for $13 as of writing).  My reasoning for picking this board is that it’s got the integrated USB to Serial converter, lots of digital inputs and importantly is narrow enough to fit on a standard breadboard with enough space to connect it.  You can find more details on this site comparing ESP8266 based boards, but as you can see below the spacing makes a big difference.

ESP8266 v2 versus v3
ESP8266 v3 (left) versus v2 (right) – big difference on the breadboard!

Okay, so what did I make with these things and how can I get a cheap environmental monitoring system out of them?

While I made several “models” with alternating sensors (photo resistors, ultrasonic distance sensors, etc.) what I made sure to include on every one of my ESP8266 based projects was either a DHT22 or DHT11.  What this meant is that everywhere I put one of these things I could get data on the temperature and humidity.

The DHTs generally require a small resistor wired between the voltage and digital input, however you can buy modules that already have the resistor on a small circuit so they’re ready to connect directly to your ESP.  Here is an example you can get on Amazon.  Additionally, I recommend the DHT22 over the DHT11 as they are much more accurate, but they’re also more expensive.

There are plenty of articles out there that will show you how to connect up a DHT to an ESP 8266 (which is not what I’m going to go into detail on in this article).  I’ve shared some code you can reuse on my GitHub repository here if you need something to get started: ESP8266 Environmental Monitor.  With that code (INO, PHP and MySQL) you can take the temp/humidity data and log it into a database, and from there all kinds of fun projects can be made because…data!

For example, I have a fun dashboard running on a old tablet that is mounted on the wall:

Environmental Monitoring Dashboard
Environmental Monitoring Dashboard

I also leveraged Fusion Charts so I could graph the temperature and humidity over time:

ESP8266 Temp and Humidity on my front Porch graphed
ESP8266 Temp and Humidity on my front Porch over the last 7 days graphed

(If you want see some of the code I used for these examples be sure to visit my WeatherUnderground PHP MySQL and FusionCharts Multiaxis PHP MySQL code repositories.

A few more pictures from some of the projects here:

I hope this inspires you to learn and try something new!


Technology, science, building things and experiencing the world. What more could anyone ask for?

Witnessing the 2017 Eclipse in the Malheur National Forest (near John Day) Oregon

Watch the video here:

I hope you enjoyed the video.  This was an amazing life experience, and while the video turned out reasonably well it doesn’t reflect but 1/10th of the awesomeness of the experience.  It was so amazing that without any good explanation for why I started whispering like I was in a church during totality (even though we were in the middle of the forest and the closest people were 1/4 mile away) and my wife, Susan, started crying – it was that good!

I’ve heard others say that experiencing this in person is vastly better than viewing a video and to this I can attest.  I’d go as far as to say that the difference is like having your first kiss versus having someone describe it to you – yes in person it really was that good!

What you cant see in the video is that the sky is an amazingly deep blue and the horizon looks like sunset all around.  Just before and just after the whole landscape had an earie low-light look which played with our senses as we’re not used the world being lit in such a way.  Minutes before the forest went silent, from constant bird calls and insect noises normal for an August to nothing more than the sound of the breeze.  It was a completely overwhelming experience.

The location we were at, and this video was taken, was in the Malheur National Forest.  We intentionally picked this location as it was in the path of totality but would be sufficiently far enough away from any major population center that we could enjoy this as a family rather than in a big crowd.  If you’ve never been dispersed camping on our wonderful National Forest or BLM lands then you need to get out there!


Planning our next eclipse visit for 2024, come join us there!


Technology, science, building things and experiencing the world. What more could anyone ask for?

Solar Electric for Home, does it save money? Introducing the Solar Electric Business Case Calculator.

I’ve always wanted solar power at my house, and always been infatuated by the idea of making my own power directly from the sun.  Once more I’ve spent countless hours as part of a renewable energy non-profit I worked with speaking with members of the public and private business about the possibility of systems they can build.

Coming out of those conversations there were always 3 immediate questions:

  1. What type of system should I build?
  2. How much will it cost to put in place?
  3. Is it cost effective (i.e. “what’s my ROI”)?

Unfortunately the excitement tends to get tempered quickly as actually building a solar system is still a custom process requiring expertise to ensure the system is sized best to meet a given set of requirements and cost basis.  At the end of the day the answer to these questions is still is a very big “it depends”.

Abe put together a good post recently on the types of systems available (#1), and we’re planning at a future date to go into more detail about how to select and cost components for a system (#2).  The purpose of this article is to share a model/calculator I’ve developed to evaluate the total cost of ownership (TCO) and the easy ability to compare against current costs so I could quickly estimate a return (ROI, #3).

I’m releasing this calculator as open source with the hopes that it will help you in your own evaluation, you can download it here:
Solar Home Business Case Calculator 1.0

Instructions for use

The calculator is an Excel workbook, when you first open it you should see the “Inputs and Summary” worksheet (aka “tab”) which, if you’re only looking to make a quick evaluation is the only worksheet you need work from.  Note that this calculator is built to show the case month by month up to year 20 (my line of thinking is that beyond this you’ll likely end up having to do a new round of replacement or maintenance anyway, so no need to go further in the analysis).

In order to fill this out you’re going to need to gather a number of details, some of these you can get from your current electric bill whereas others are beyond the scope of this article.  All the fields in green need to be filled in:

Solar Business Case Inputs – Oregon Example

After you’ve filled in the detail you’ll see a summary after 20 years of the baseline (i.e. “do nothing”) costs versus the total costs of your new system, plus the % difference (i.e. “ROI”).  I’ve also included a graph that shows where you are month-by-month:

Solar Business Case Summary – Oregon Example

Note: if you would like to explore this further and need help filling out the details you can contact us at and ask – for a fee, we’ve got a few members on our team that can help consult with you to determine what the right size is and to evaluate your case in further detail.

Some Final Thoughts

Cases very (wildly) based on local variables such as your cost of electricity, incentives (i.e. tax incentives), how much you consume, and how much your system is expected to produce.  Personally, the case at my house is not a positive one (from a purely financial ROI perspective):

Solar Business Case – Erik’s House

The reason for this is actually quite simple when you get into the details:

  • Electricity here in Southwest Washington state is inexpensive (I live near the Columbia River in SW Washington – the Columbia River basin produces over 38,000 MW of power so we’re in the fortunate position to have abundant renewable hydroelectric power).
  • I consume large amounts of electricity (living in the country, heating/cooling/pumping water, family size, etc.) and would therefore require an expensive system (I put together a detail install estimate which came to over $64,000).
  • Washington State and my local Clark County do not have as large incentives as some other locales – as you’ll see when you start playing with the detail incentives can often make or break the case.

For me personally, I’m hoping the cost of the system will come down in the near future – if I can get the total cost around $40,000 then it starts to look much better.

Hope you find this helpful and be sure to post any comments/questions you have!


Technology, science, building things and experiencing the world. What more could anyone ask for?

DUMVOIN Surface Pro Adaptor Review

I’ve been using the Microsoft Surface Pro for a few years now (first the 3, then the 4) but I have a recurring issue where if the device is low on power and needs charging at the same time my phone is low and needs charging and I plug them in at the same time it occasionally overloads the OEM adaptor causing it to shut down.  Until now I hadn’t replaced the adaptor with something else as I was waiting for a good option that included more than one USB charging ports and supported faster charging such as Qualcomm’s Quick Charge or in the case of my current smartphone (Samsung Galaxy s8) Fast Charging.

The product I ended up selecting I had my eyes on for a while, but it had some really bad reviews on Amazon, is made by a company called Dumvoin (Taiwan based) so I avoided it for some time.  Last week I decided that it was worth the low $25 price to give it a shot anyway.

The reason I selected this product is that it was small enough to fit comfortably in my travel bag and had 2 quick charging ports.

Given the low reviews on Amazon I felt a few of you would like to see something more comprehensive and objective (I was not compensated in any way to write this review, though clicking on our affiliate links would be appreciated).

First the verdict – I’m giving this 3 stars on Amazon out of 5, or if this was a grade I would give it a “C”.  Simple reason is that it does what it’s supposed to do, but they could have done so much better in putting together the product.  Read on for why!


  • QC and FC ports work exactly as advertised
  • Good size/shape


  • It buzzes, it’s not loud but it’s noticeable when you’re in a quiet room.
  • Dumvoin, the name alone is probably losing these guys sales.  I’m going to assume that it means something to someone back in the home designer’s country – but in the American market you need to pick a name that exudes quality (and perhaps not similar to the word “dumb”).  I’m expecting it’s only a matter of time before I find myself in a meeting and I get the question “what kind of name is that?”
  • The charging light is always on, unlike the OEM adapter where it’s only on when actually charging – this may seem trivial but with a magnetic connector I would argue that it’s important to have good positive feedback that charging is occurring else you could end up thinking you’re charging when you’re actually not (see the picture to the right for how easy this is).
  • Build quality: This generally feels fairly cheap, especially on the connector itself.  I added a few pictures, but it’s just as obvious in how the product feels.


I do have good news in that two of the biggest complaints I saw on the Amazon reviews was that this “gets hot” and “charges slow”.  I have never seen this get excessively hot, even when charging multiple devices (in fact as you’ll see below in my tests it runs cooler than the OEM adaptor).  On speed I ran a test with 2 Surface Pro 4s starting at the same charge and logged the speed of the charging, the results were that charging occurred at the same rate as the OEM adaptor.  If you think about it this makes sense, if they’re both rated at 12v at 2.58Amps then they’re both going to be pushing the same 30.91 watts.  Now I would argue that this should be higher/faster in general, but my point here is that you should see charging occur at the same rate.

Power Adaptor Charging Data
Power Adaptor Charging Data

Anyway, hope you find this helpful!


Technology, science, building things and experiencing the world. What more could anyone ask for?