DIY Solar monitoring.

[Craig]

If anybody has any DIY complete solar monitoring ideas or finished products lets discuss them here. The idea of this thread is to brainstorm ideas and discuss what works and does not work. The other forum members and I who decided to post this topic were mainly think Arduino or Single board computer related systems.

I know there are many things that can be bought but after this is a DIY forum and buying pre built things to me are just no fun. I mean why spend 100 bucks on something that is turn key. When you can design and redesign your own and in the process spend ten times that much. If you understand this we will have great fun LOL

 

[ImpatientMaker]

I found this project which has some software available on the author's Github page.

 

[Craig]

I found this project which has some software available on the author's Github page.

Great find gonna need to study this

 

[Will Prowse]

Using a shunt and monitor screen, and using a cheap wifi security camera faced at the screen, is what I am doing on my latest project. I can check on the system from anywhere in the world, and control various things remotely with wifi switches. Dead simple and costs pennies. Working on a video right now about it.

 

[Craig]

Using a shunt and monitor screen, and using a cheap wifi security camera faced at the screen, is what I am doing on my latest project. I can check on the system from anywhere in the world, and control various things remotely with wifi switches. Dead simple and costs pennies. Working on a video right now about it.

Gosh don't make it so darn easy it spoils the fun.

I actually tried this and with the Blink camera I had I couldn't get it to focus properly. That's not to say it wouldn't work with another camera.

I'm also looking to do some data logging so I plan to record all meters every so often to see when and from what arrays I get most power. My remote system is 15 hour drive from my home so I desire something a little more robust.

But yes I agree a web cam is a quick down and dirty approach.

One question does anybody know if a drok style shunt meter Can be hacked to report screen readings to an IOT device.

 

[morth]

Using a shunt and monitor screen, and using a cheap wifi security camera faced at the screen, is what I am doing on my latest project. I can check on the system from anywhere in the world, and control various things remotely with wifi switches. Dead simple and costs pennies. Working on a video right now about it.

Just did something similar when doing a run down test in my crawl space and didn't feel like going down there every 30 minutes to check on things. Worked great. Wifi switches would be a cool addition to shut stuff down remotely. I have been using iHome control switches for a couple years and for the most part have worked fine and they are rated for 15 amps at 120V ac, so they are useful for dehumidifiers and refrigerators.

 

[ImpatientMaker]

I have a shunt just for this purpose and plan to play around with some voltage and current sensors with Arduino so I can do as Craig said and log this stuff with Telegraf, etc.

 

[Craig]

So Im trying 3 ways to measure current

A. https://www.aliexpress.com/item/32852979678.html Shunt style Hall effect sensor
B. https://www.aliexpress.com/item/32803032597.html?spm=a2g0s.9042311.0.0.27424c4doaEyd1 Clamp style Hall effect sensor
C. Measure voltage drop across current shunt with 16 bit ADC.

The problem is with methods A volts per amps produced by the sensor does not seem to be linear

for example at 1.6 amps my sensor shows 42 amps per volt or .038 volts but at 26 amps the sensor shows 46.6 amps per volt or .564 volts from device.

Im comparing my measurements with a Drok voltage /current meter.

I have sensors connected to ads1115 ADC and a raspberry pi.

Anybody have any Ideas.

Had simlar experience with method B
Method c I just got working. But have not had a lot of time to test yet.

 

[eddie1261]

Using a shunt and monitor screen, and using a cheap wifi security camera faced at the screen, is what I am doing on my latest project. I can check on the system from anywhere in the world, and control various things remotely with wifi switches. Dead simple and costs pennies. Working on a video right now about it.

Did you include the IP so we can ALL check it?

 

[ImpatientMaker]

So Im trying 3 ways to measure current

A. https://www.aliexpress.com/item/32852979678.html Shunt style Hall effect sensor
B. https://www.aliexpress.com/item/32803032597.html?spm=a2g0s.9042311.0.0.27424c4doaEyd1 Clamp style Hall effect sensor
C. Measure voltage drop across current shunt with 16 bit ADC.

The problem is with methods A volts per amps produced by the sensor does not seem to be linear

for example at 1.6 amps my sensor shows 42 amps per volt or .038 volts but at 26 amps the sensor shows 46.6 amps per volt or .564 volts from device.

Im comparing my measurements with a Drok voltage /current meter.

I have sensors connected to ads1115 ADC and a raspberry pi.

Anybody have any Ideas.

Had simlar experience with method B
Method c I just got working. But have not had a lot of time to test yet.

This is using a different hall effect IC but it looks helpful.

Also, have you looked at Induction style sensors? This one has a sample Arduino circuit diagram (and goes to 100A).

 

[Craig]

This is using a different hall effect IC but it looks helpful.

Also, have you looked at Induction style sensors? This one has a sample Arduino circuit diagram (and goes to 100A).

Those do AC only as far as I can tell

 

[Craig]

Did you include the IP so we can ALL check it?

When I get it set up I will

 

[ImpatientMaker]

I have an Epevar Tracer 30A scc and it came with the serial<>USB cable. I know there are Windows apps but I am tech masochist so I'm looking for a Linux (or other OSS) solution. I found this thread with a lot of info on a driver for Linux on the Raspberry Pi (so I assume it will work on other Arm platforms).

 

[WoodsieLord]

for example at 1.6 amps my sensor shows 42 amps per volt or .038 volts but at 26 amps the sensor shows 46.6 amps per volt or .564 volts from device.

Craig, would you consider making a simple "lookup table" ? (hardcoding it inside the arduino's code, for example). I think this behavior is intrinsic to the shunt resistor/material/whatever. So, I would expect that for every [shunt]+[IoT micro controller] a few tests would be required to build its lookup table.

Say, you end up with a table that shows [Amps] vs [volt drop per Amp] (an example, I'm making these numbers up):

1 amps -> 41.8 amps/volt
5 amps -> 42.3 amps/volt
10 amps -> 43.8 amps/volt
...
40 amps -> 50.1 amps/volt

My idea is to achieve a simple approximation without any strong maths or weird libraries to save program space.
You can always check the IoT Shunt against your trustworthy instrument for deviations so you can take them into account.

I'm totally into this since I don't have (nor will I be able to afford) an MPPT controller, so I have no usb/serial port to get any info at all.
I have an AGM battery bank without a BMS, so I'm very interested in this approach.

Regards!

 

[Craig]

Craig, would you consider making a simple "lookup table" ? (hardcoding it inside the arduino's code, for example). I think this behavior is intrinsic to the shunt resistor/material/whatever. So, I would expect that for every [shunt]+[IoT micro controller] a few tests would be required to build its lookup table.

Say, you end up with a table that shows [Amps] vs [volt drop per Amp] (an example, I'm making these numbers up):


My idea is to achieve a simple approximation without any strong maths or weird libraries to save program space.
You can always check the IoT Shunt against your trustworthy instrument for deviations so you can take them into account.

I'm totally into this since I don't have (nor will I be able to afford) an MPPT controller, so I have no usb/serial port to get any info at all.
I have an AGM battery bank without a BMS, so I'm very interested in this approach.

Regards!

I have considered that and may use it. The only thing holding me back is that figured if I did it that way I was doing something wrong.

I think one problem Im having is these cheap sensors may not be that accurate or may need calibration often.

 

[gnubie]

I think one problem Im having is these cheap sensors may not be that accurate or may need calibration often.

If you set the ads1115 to use one of its internal voltage references they are very stable and quite accurate. I have several monitoring battery voltage in remote locations and did a fair bit of testing before settling on using them. It wouldn't surprise me to find that there is a cheapie knock off Chinese version of the chip that has terrible performance.

 

[bulrush]

I found this project

Great way to mount solar panels which cannot be on a roof! If I don't use a certified solar panel installer (expensive) then my roof warranty is void. I paid extra for that warranty.

 

[mrevesz]

I'm going to be implementing arduino into the off-grid system I am building. The arduino is needed in my case for a few reasons:
1. I want to be able to use the BMS as a switch to turn off the inverter, but my inverter requires a pulse signal to turn on and off so I cannot use the mosfet circuit of the BMS as the switch directly
2. I want to be able to control the load dumping to a 50gal drum converted to a water heater, so that I don't boil the water away
3. I want to turn on and off case fans that will cool the box in which I will house the batteries and all other electrical components of the system.
4. I want to turn on and off 12V loads from the batteries when voltage is low

It's going to be quite a complicated circuit coming from the arduino to do all the sensing, and relay switching needed. I'll be starting tomorrow on figuring out which pins do what, and laying out the PCB circuit that will just be a bit of perf board.

 

[A J]

RE: Personal solar power production record keeping and statistics

Craig; Thank you for the encouragement to tackle programming platforms.
FIVE WHOLE YEARS TO GET THIS FAR using Arduino and Pi and lots of ...

gnubie; Thank you for your help with the serial port hints.
I have found the serial problem ? !

Over the past four days I've progressed quite a ways in using Node-Red, extracting data to CSV, then opening in LibreOffice, exporting to my Windows laptop, I'm yet to play with it.
During the day I found the data was coming through very nicely until I turned on the inverter "with a particular load" I would loose and/or have incorrect data, finding the interfering load I proceeded with out that load.
During the night, the same thing with different loads? Dumping those loads.
I'm a bit peeved the ripple from the inverter with devices attached have an effect on the controllers ability to send data!!

My next move is to make a Dashboard with most of the available data.
Then have the Pi powered by the batteries, not using the AC/DC adaptor, tied it a while back and it did not like the inverter power at all.
Thanks again ..

 

[Steve_S]

I started tinkering with Raspi, Node Red, Grafana & InfluxDB using Modbus -> IP to my Midnite Classic-200 controller and I just got the latest MODBUS specs & info for my Samlex EVO-4024 Inverter (not released publicly). I posted an initial setup here at Midnite: http://midniteftp.com/forum/index.php?board=73.0 feel free to peruse and use anything handy there.

This is a "winter" project which I will be working on, once the ground is covered and I'm tired of having a frozen face. (Dang Canadian Winters !)