Posts tagged with "sensors"
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Solar Panel Project Update - Part 5
This is the final update in the solar panel project series for now. Hopefully by now you must be quite bored with the updates because I am sure no one is going to build a project that is exactly same as mine. But in case you are following along, you might have picked up some things that you did not know earlier or may be you found somethings that you could have done differently. The reason I am writing is to keep a journal of things. While I fixed most of the issues with my setup, I still had a couple of problem that don’t happen frequently which makes it difficult to debug. In this post I will discuss the problems and my solutions. May be there are better solutions, but these are ones that I could come up with. A reader was lamenting that my posts are too short so I let this post go as long as it needs to be. So enjoy :).
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Solar Panel Project Update - Part 4
As I mentioned in my last post about solar panel setup, there still a few more issues with my sensors. One of them is temperature drift. When the weather is cool like early in the morning, the DC current sensors read one value and in the evening when the temperature is hot, they read a slightly different value. The difference is quite small but get magnified when doing the calculations. For example, in the night around 7 pm when there is no solar power, the sensor would read 2.5V which after all the transformations turns out to be 0 amps of current. All good. Then in the morning say around 5 am when there is still no sun, the sensor would read 2.52V. Not much of a difference, but it get magnified as I will soon show you.
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Solar Panel Project Update - Part 3
In my previous post I explained how I improved the accuracy of my DC sensors using ADS1115. But there is one problem though. The ADS1115 gives accurate reading even when the supply voltage keeps changing. Yet, the sensor values will not be correct. The reason is that if the supply voltage is changing, the reading on the sensor will also change, but the accuracy of the reading will be stable because ADS1115 is independent of power supply voltage fluctuations. For example, let’s say the supply voltage is 2.5V, then when there is no current, the DC current sensor will read 2.5V, and in the code we assume the current is 0 at 2.5V. Now if the supply voltage drops to 4V then the sensor will read 2V, which is still the mid point and indicates 0 current. But in the code we have a hard coded number that 2.5V is the midpoint and we mistakenly assume that some current proportional to -0.5V is passing through the wires. That is the problem.
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Solar Panel Project Update - Part 2
This is a continuation of my previous post giving updates about my solar panel setup. As you will probably remember from that post, I found a good sensor that would measure AC voltage and current accurately and I was satisfied and very confident about the data coming from the sensors. However, I cannot say the same about my DC measurements. Many components in the system should be measured in DC including solar panel current, battery voltage and current etc. My initial set of sensors were not accurate and used to drift quite a bit with supply voltage and ambient temperature. So I set out to find better sensors and upgraded them and I cover part of that story in this post.
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Solar Panel Project Update - Part 1
It has been a while since I gave any updates on my solar panel project so I thought I should write a post on it. This can get pretty technical so if you are not into electronics or software, you can skip. Since I last reported about my design I’ve made a few changes mainly to increase the stability of the system. What happened was that in the long run, I found some problems that rear their head sometimes intermittently. As a result I had to change the design to recover some components from their weird state. In addition I reduced the variability of readings by the sensors.
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Solar Panel Output Under Various Conditions
In a previous post I talked about how my sensors tell a story regarding our power usage. There are still many more stories that the sensors can tell us about how we use electricity and how much solar power is being generated. Have you ever wondered how the solar power output looks like during the course of a day? Let me give you a hint – it almost looks like a half-rectified sine wave. It was a really interesting discovery. How about the output of solar panel when the day is cloudy? I have answers to all these questions and more in this post.But first let me walk you through the whole setup that I have at home.
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Sensors Tell A Story
After having set up my solar panel, I installed a bunch of voltage and current sensors in various places to collect data about my power usage and also to keep track of how much solar energy is being generated. The plan was to optimize and maximize solar power usage. I want to eke out every bit of power from the panel and optimize the hell out of solar energy. I also wanted to build some visual artifacts (graphs) out of the data. If you are like me, crazy about data, and data analysis, then this post is for you.
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Collecting Data From Solar Panel Setup
After having setup the solar panel on our terrace, I wanted some data. Specifically I wanted to know the panel output over the course of the day and how much energy savings we are enjoying. The solar management unit (SMU) gives some details about the instantaneous power output and energy savings. But for some reason I felt the numbers look a bit too optimistic. Moreover I could not get more granular data from it. I guess it has more to do with not invented here syndrome. Either way I decided to hook up some sensors myself to gather all the data I'd like from it.
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