Solar Monitoring (1 Viewer)

[Evildoody]

I set up my Raspberry Pi 2 in the MH today, this logs and charts the solar activity.
I have the Raspberry Pi connected to an USB RS485 adapter and this connects to the RJ45 (for RS485) on the Epever Tracer 4210A MPPT charge controller.
When I am away from the MH I can now check the battery charge status and power on/off any attached load.



If anyone is interested there is a guide on how to do this here :-

http://randomsporadicprojects.blogspot.co.uk/2016/11/instructions-for-creating-dashboard-to_9.html

 

[hilldweller]

Well I'm impressed !

 

[Pausim]

Well I'm impressed !

So am I. I even understood one or two of the words in the instructions but not enough to do more than be impressed.

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[Guigsy]

This is really cool. I was worried that a Pi eats through about 5w, but checking it's probably only 1-2w most of the time because it's idling.

I've got a Tracer with an external control screen, but it's pretty awful for anything other than what is happening right now. This would be a useful upgrade. Thanks.

 

[Evildoody]

This is really cool. I was worried that a Pi eats through about 5w, but checking it's probably only 1-2w most of the time because it's idling.

I've got a Tracer with an external control screen, but it's pretty awful for anything other than what is happening right now. This would be a useful upgrade. Thanks.

Pi 2 State Power Consumption
Idle 220 mA (1.1W)
ab -n 100 -c 10 (uncached) 450 mA (~2.3W)
400% CPU load (stress --cpu 4) 400 mA (~2.1W)

NB. I never wrote the guide above, some guy called Andrew did. I just followed his guide

 

[hilldweller]

This is really cool. I was worried that a Pi eats through....

Yes, if it's running 24/7 it's too much, I would have used Arduino and dramatically reduced the current.

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[Evildoody]

Yes, if it's running 24/7 it's too much, I would have used Arduino and dramatically reduced the current.

Do you think?, I am pulling in a minimum of 80W a day with the 2 x 150W PV's at this time of year (mostly overcast and low sun).

I have 2 x 110AH batteries (1320W each). So technically if I only drain to 50% of capacity I have 1320W of available power (from a fully charged battery*).

*now taking into consideration the temperature at this time of year my true battery AH rating at 100% charge is now circa 71.5 AH (858W) (based on 0 degrees celsius)

in my case my Raspberry Pi is drawing say 2W (48W a day), so this should equate to a run time of 429 hours (basing this on a 12V 2W draw and not a 5V 2W draw) to deplete my battery bank to 50% capacity without solar. So it would seem the low output from my solar array is still more than adequate, even at this time of year to more than compensate for the battery drainage from the Pi?

but yes the Arduino would be better still, I had the Pi2 sitting gathering dust

 

[Guigsy]

My thought was that you're getting about 80Wh per day at the moment, but using half of it just to monitor. Yeah, with 300w of panels, you're fine, but it's still quite a large loss. I've got a single 280w panel, but the van is parked in the shade at this time of year, so it'd probably be too much for me. Arduino would be lower power, but then you've got no web interface. Maybe a Pi Zero?

What this does show is how feeble solar is in the UK in winter, even with a pair of solar panels approaching the area of a domestic door!

 

[Evildoody]

My thought was that you're getting about 80Wh per day at the moment, but using half of it just to monitor. Yeah, with 300w of panels, you're fine, but it's still quite a large loss. I've got a single 280w panel, but the van is parked in the shade at this time of year, so it'd probably be too much for me. Arduino would be lower power, but then you've got no web interface. Maybe a Pi Zero?

What this does show is how feeble solar is in the UK in winter, even with a pair of solar panels approaching the area of a domestic door!

Yes, with a Pi zero you can half my power consumption figures.

Winter = crap solar and crap battery storage due to the cold :-(, in summer I will have too much power and then might just install a workstation to utilise this free energy

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[hilldweller]

Do you think?,

On a theoretical level yes. If you can do the job with 100x less current then it's better.

Many vans these days can't last 3 weeks without some charge and still start the engine all due to inefficient electronics.

But as long as it works for you, you are happy.

I've been working on some home automation with wall mounted switches I need to run off battery, I'm heavily into micro amps.

I am a fan of Pis ( looks bad eh ) great when more horsepower is needed. I'm just working on a Rock64 for some serious horsepower.

 

[hilldweller]

but then you've got no web interface.

Investigate ESP8266, a bit power hungry but staggering what it can do for a fiver.

 

[Evildoody]

On a theoretical level yes. If you can do the job with 100x less current then it's better.

Many vans these days can't last 3 weeks without some charge and still start the engine all due to inefficient electronics.

But as long as it works for you, you are happy.

I've been working on some home automation with wall mounted switches I need to run off battery, I'm heavily into micro amps.

I am a fan of Pis ( looks bad eh ) great when more horsepower is needed. I'm just working on a Rock64 for some serious horsepower.

I wasn't disagreeing with you in regards to less power consumption the better, the Pi 2 was spare and sitting available and the math in my particular case worked out more than fine for my requirements. The Rock64 looks good though, for anyone else interested there is a review here https://www.youtube.com/watch?v=ZejkWra-Mfc

The benchmarks look pretty good against the competition, for power the Tinker board seems to have it beat though

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[hilldweller]

The Rock64 looks good though, for anyone else interested there is a review here
https://www.youtube.com/watch?v=ZejkWra-Mfc
The benchmarks look pretty good against the competition, for power the Tinker board seems to have it beat though

My story behind this. I've used a Pi3 screwed to back of TV to watch Eurosport on line. But all too often the poor LAN interface and limited RAM on the Pi causes drop outs.

Plan B, buy Tinker. I could not get that to view Eurosport. It was a while ago but I think all I could get it do was play at about 2x real speed. I returned it within 14 days, could not be bothered to struggle.

Then I saw Rock64, which seems to wipe the floor with Pi and Tinker, so bought one. Sadly this is really lacking in solid distros but it took so long to get here I'm persevering with it and now have one that plays Eurosport.

ROCK64 is a credit card size 4K60P HDR Media Board Computer powered by Rockchip RK3328 Quad-Core ARM Cortex A53 64-Bit Processor and support up to 4GB 1600MHz LPDDR3 memory

That spec would have been a real top of the range desktop PC not that long ago, in fact it is similar to what I am typing on right now.

 

[Evildoody]

My story behind this. I've used a Pi3 screwed to back of TV to watch Eurosport on line. But all too often the poor LAN interface and limited RAM on the Pi causes drop outs.

Plan B, buy Tinker. I could not get that to view Eurosport. It was a while ago but I think all I could get it do was play at about 2x real speed. I returned it within 14 days, could not be bothered to struggle.

Then I saw Rock64, which seems to wipe the floor with Pi and Tinker, so bought one. Sadly this is really lacking in solid distros but it took so long to get here I'm persevering with it and now have one that plays Eurosport.

ROCK64 is a credit card size 4K60P HDR Media Board Computer powered by Rockchip RK3328 Quad-Core ARM Cortex A53 64-Bit Processor and support up to 4GB 1600MHz LPDDR3 memory

That spec would have been a real top of the range desktop PC not that long ago, in fact it is similar to what I am typing on right now.

Yes, that is the problem. Synthetic benchmarks favour one system over the other, when in fact your particular requirements work out better on hardware that apparently scores lower.
Not to mention current distributions available for said hardware, unless you are a linux guru you are stuck with what is available.

 

[hilldweller]

I was heartbroken at the poor distro on the ASUS. I've used ASUS motherboards since they had valves in them and expected perfection.

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[Evildoody]

I was heartbroken at the poor distro on the ASUS. I've used ASUS motherboards since they had valves in them and expected perfection.

ASUS should of done their market research and advertising better. That is the only reason that Pi is so mainstream.

 

[Vansflyer]

That is clever stuff, but you lost me in the second post... if it works please translate it for us "non geeks". I get P over I / R but that's about it

 

[Evildoody]

That is clever stuff, but you lost me in the second post... if it works please translate it for us "non geeks". I get P over I / R but that's about it

The second post was hilldweller saying "Well I'm impressed !", so if you are lost there, then you are on your own

In a nutshell, I have a Raspberry Pi 2 that has a USB to RS485 adapter plugged in to it https://goo.gl/QzK2ug
this is then physically connected between the Pi and the solar charge controller.

On the Raspberry Pi 2, I install nginx (web server), php (PHP: Hypertext Preprocessor) and Mysql (database engine)

I create a few text files that contain information pertaining to the address of the RS485 adapter (in my case /dev/ttyUSB0) and specify the database username and password that I created in the MYSQL database.

TLDR

The Raspberry Pi reads the Solar panel statistics from the charge controller via the RS485 adapter and writes them to a (Mysql) database, a webpage (that runs a PHP script) then reads the values from the database (performs some arithmetic) and writes them to a webpage that you can now access via a webpage (fancy graphs are used to represent this data)

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[quilkin]

Investigate ESP8266, a bit power hungry but staggering what it can do for a fiver.

I've started to build a campervan monitor with ESP8266; it can be put into a deep sleep mode most of the time. To record values it only needs to wake up every 5 or ten minutes, then be awake for about 5 seconds (that's mostly waiting for the internet connection to fire up). So the overall power consumption is trivial.

 

[Evildoody]

I've started to build a campervan monitor with ESP8266; it can be put into a deep sleep mode most of the time. To record values it only needs to wake up every 5 or ten minutes, then be awake for about 5 seconds (that's mostly waiting for the internet connection to fire up). So the overall power consumption is trivial.

I'll have a look into that, thanks

===============================================================
it's almost 9 PM, my MH is in the countryside and some how it is pulling in a whopping 0.22 unusable volts in darkness!

 

[andy63]

A great project , and instructions / guide
Well impressed.. but well beyond me... but still enjoy the read..
Andy.

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[hilldweller]

I'll have a look into that, thanks

===============================================================
it's almost 9 PM, my MH is in the countryside and some how it is pulling in a whopping 0.22 unusable volts in darkness!

I think you are onto something BIG here.

 

[Guigsy]

ESP8266s are great... until you realise that a Pi Zero with WiFi is less than a tenner. If you have an application where it can sleep for 5 minutes, collect data, transmit it and then go back to sleep then the ESP wins. However, anything that needs a continuous interface so you can see the results means the ESP isn't that much more efficient.

My house is filled with Sonoff Touch and T1 light switches which have ESP chips in them. They are have all been flashed with Tasmota firmware and all the fun automation stuff is managed with a Raspberry Pi 3 running Home Assistant and an MQTT broker. Works out far cheaper than Philips Hue light bulbs and unlike Hue setups, I can still use my light switches. I've not managed to justify this in the van yet though.

 

[hilldweller]

I've started to build a campervan monitor with ESP8266; it can be put into a deep sleep mode most of the time.

Are you a fan of The Man With a Swiss Accent ?

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[Evildoody]

I think you are onto something BIG here.

Must be tapping into dark energy

 

[Evildoody]

Are you a fan of The Man With a Swiss Accent ?

perhaps

https://www.youtube.com/channel/UCu7_D0o48KbfhpEohoP7YSQ

 

[hilldweller]

perhaps

Love the man.

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[Evildoody]

Love the man.

I also love AVE, BIGCLIVE.COM and ELECTROBOOM to name a few . The former and latter use comedy a lot, but they really know their stuff and that helps keep it entertaining as well as informative.

 

[quilkin]

ESP8266s are great... until you realise that a Pi Zero with WiFi is less than a tenner. If you have an application where it can sleep for 5 minutes, collect data, transmit it and then go back to sleep then the ESP wins. However, anything that needs a continuous interface so you can see the results means the ESP isn't that much more efficient.

Haven't got into Pi's (yet?!) but my ESP sends its data by wifi (using an old phone, or maybe later a MiFi unit) to a database in the cloud; the web page interface will also also be there (or I can just use Excel to load in and display data) . The phone also sends GPS data to the same database, so others can see where I am (or I can track the van if it ever goes missing).