solar monitoring using MRL

This MRL program monitors the solar output data streaming from an Outback Mate. My system has 3 solar chargers. One for each solar array, two controllers are Outback MX60’s and one is an Outback MX80. The solar panels are hooked up in series and feed into the solar chargers. Hooking the solar panels in series allows for a smaller gauge wire from the panels and less voltage drop (higher voltage/less current). Each solar array has 8 220 watt panels. The solar chargers charge 24 volt batteries. I have 8 sets of batteries installed and am able to enable/disable each battery pack. So I don’t have all the battery packs hooked to the system at the same time. The red looking batteries are 6 volt and are meant for a solar system. The black batteries and others, I have picked up at a salvage yard and are 12 volts. So four 6 volt batteries in series gives me 24 volts, or one battery pack, and two 12 volt batteries in series does the same. I have two outback FX DC to AC inverters which supply 120 VAC each to my shop. With two you can link them to give 220VAC. The Outback parts are connected together using Outback Hub. You can monitor and program each part by use of an Outback Mate which also plugs into the hub. The Mate streams out serial data on each part in the system at 19200 baud all the time. One difficult thing is the Mate’s serial port is opto isolated and powered by the serial line plugged in to it. Therefore the software needs to be able to set DTR and RTX (thanks Kev). I also have a battery monitor unit from Outback that allows you to monitor the current in and out of three sets of batteries.

The MRL program, I wrote, receives the data from the Mate and displays it on a PC. Or a device running MRL. If I get everything setup on raspberry pi running MRL I should be able to remotely log in and monitor my power system. I could even have it talk to me in different languages and cycle my battery packs. The first step was being able to collect and display the data. I started working on the power system for my shop in 2008 and have gone through a lot of batteries and changes. Solar batteries seem to last about 5 years and 12 volt batteries much less. I am hooked to the grid for backup power, but do not feed back into the grid. There are many rules in the US about feeding back to the grid.

Two sets of my panels I built on bucket truck backs or lifts so I can hydraulic angle and rotate them. I only angle them seasonally, around four times a year. In the summer months the panels are pretty flat and I produce enough power, there is no need to rotate them. In the winter months at my latitude, I see an increase in power produced if I turn them and scrape off the snow. I have installed everything myself, more as a hobby. I don’t expect to break even on the cost, as I keep adding to and changing the system.

I am not really a programmer but have had the MRL program running more than a week.

Examples of the output of the six Outback parts being monitored by the MRL program:

Current date and time: 2018-06-21 16:55

('FX DC to AC inverter bat volts=27.0', ' AC volts=120', ' AC amps=1', ' AC Mode=0')

('FX DC to AC inverter bat volts=27.0', ' AC volts=120', ' AC amps=8', ' AC Mode=0')

('Bat Temp in C=41', ' ShuntCur1=0.2', ' ShuntCur2=3.1', ' ShuntCur3=0.4', ' Battery Percent Charge=100')

('MX solar charger PV volts=96', ' PV amps=7', ' charg Bat amps=22')

('MX solar charger PV volts=82', ' PV amps=10', ' charg Bat amps=30')

('MX solar charger PV volts=101', ' PV amps=2', ' charg Bat amps=7')

 

Current date and time: 2018-06-21 16:57

('FX DC to AC inverter bat volts=26.8', ' AC volts=120', ' AC amps=1', ' AC Mode=0')

('FX DC to AC inverter bat volts=26.8', ' AC volts=119', ' AC amps=8', ' AC Mode=0')

('Bat Temp in C=41', ' ShuntCur1=0.2', ' ShuntCur2=2.8', ' ShuntCur3=0.3', ' Battery Percent Charge=100')

('MX solar charger PV volts=96', ' PV amps=6', ' charg Bat amps=21')

('MX solar charger PV volts=82', ' PV amps=10', ' charg Bat amps=29')

('MX solar charger PV volts=98', ' PV amps=4', ' charg Bat amps=13')

 

Current date and time: 2018-07-05 15:55

('MX solar charger PV volts=97', ' PV amps=4', ' charg Bat amps=16')

('FX DC to AC inverter bat volts=25.2', ' AC volts=120', ' AC amps=0', ' AC Mode=0')

('FX DC to AC inverter bat volts=25.2', ' AC volts=120', ' AC amps=0', ' AC Mode=0')

('Bat Temp in C=38', ' ShuntCur1=0.0', ' ShuntCur2=9.9', ' ShuntCur3=1.1', ' Battery Percent Charge=90')

('MX solar charger PV volts=69', ' PV amps=8', ' charg Bat amps=22')

('MX solar charger PV volts=80', ' PV amps=8', ' charg Bat amps=24')

 

Current date and time: 2018-07-06 13:42

('1', ' FX DC to AC inverter bat volts=25.2', ' AC volts=119', ' AC amps=0', ' AC Mode=0')

('2', ' FX DC to AC inverter bat volts=25.2', ' AC volts=119', ' AC amps=0', ' AC Mode=0')

('C', ' Bat Temp in C=37', ' ShuntCur1=4.2', ' ShuntCur2=4.4', ' ShuntCur3=0.1', ' Battery Percent Charge=90')

('E', ' MX solar charger PV volts=88', ' PV amps=3', ' charg Bat amps=11')

('F', ' MX solar charger PV volts=78', ' PV amps=5', ' charg Bat amps=16')

('G', ' MX solar charger PV volts=76', ' PV amps=5', ' charg Bat amps=15')

 

 

Kakadu31's picture

Really nice project you got

Really nice project you got there, I hope you have some safety features running for it ;)

The increase in effieciency at lower temperatures is due to a better efficiency factor for standart Si-solar-panels at lower temperatures. (Atleast in theory of the physochemical reactiosn taking place, aslign as the sun shines with the same energy/area)

wvantoorn's picture

If i may, can i ask what

If i may, can i ask what those solar panel and chargers and controllers cost? I am thinking of going solar because i have me entire roof pointed to the south (atleast 1 half of the roof) and i couold fit many panels there. Because i already have almost only 12 volt lighting i am thinking about solar for a long time now.

Impressive setup!

harland's picture

costs

In 2008 I paid $523 (US) for the solar controllers MX60

In 2008 I paid $1950 for the inverters FX3524

the panels were $587 plus shipping  which was a lot, or around $2.20/watt

In 2017 my 220 watt panels cost around $1/watt plus shipping

In 2017 I paid $571 for inverter FM80

The Outback equipment has held up and not been replaced

on 2 of my orders for panels one came broke, and the metal corners get banged up

Solar panels are big and not well packed 

The hydraulic lifts that I built the first and 2nd arrays on cost $1000 from a salvage yard

As I mentioned, I think of it as a hobby with some return on the costs, "Free" electric

 

 

Spawn32's picture

Very nice setup Harland :)

Very nice setup Harland :)

How many watts can thise 3 pannels produce dyrring a month ?

wvantoorn's picture

I totally understand, and it

I totally understand, and it is a hobby, but i really love the idea of green electricity, and "free" electric, but it still is a big investment. Here in holland we do have a fund where you can apply for a partial refund, but in the end for many it still is the question, what is cheaper in the end, and in rural areas like where you live i can see how the grid can be difficult but in a small country like the netherlands i question if ion the end it would be rectifiable. 

Ever thought about wind energy?

harland's picture

questions

Hi Spawn32

I can sort of answer that question. 220 watts times 24 panels = 5280 watts or energy per hour. In my area, upstate NY, USA, the Solar-Insolation-Data tells me that I average 3.16 hours of sunlight a day on average over the year. So 5280 * 3.16 = 16.7KW per day. That times 30 days yields around 500 KW per month. The electric company is charging my shop $.21 cents per KW hour. So I should be saving around $105 per month. This is really not quite right as in the summer I get a lot more sun then 3 hrs. and I cannot use it all and am sending it to a dump load (heater). I still pay another charge just to be hooked to the grid. If some one sees an error in my math please correct me.

Hi Wvantoorn

I have tried wind energy several times. And in the picture of my shop you can see a windmill up in the upper left corner. It is a Windblue windmill and is up 50 ft. It uses a car alternator that is rewound so It produces more energy at less RPMs. I have had 2 Bergey BWC XL’s which did not hold up very well. Several problems over the 5 years that I had them up and not good luck with support from Bergey. I all so made a vertical windmill that destroyed itself after about 2 years, I thought it was a good idea as it does not have to turn to face the wind. You are right that it is cheaper to just by electric. But like most people using MRL, we just like to build stuff. All of the windmills end down AC power to lessen the loss and it is turned into DC in my shop.

 

kwatters's picture

Historical Data Tracking

wow, super cool harland!  I figure the next step should be to track the history of all this data so you can render some graphs and stuff :)

The "solr" service could do this, by indexing all this data and then providing the ability to search and sort through that data to render some graphs about how the system is performing over various time intervals.

Other folks like to use elastic search + kibana to do some of this visualization.   either way, i love this IoT use case!  I'd really love to see you be successful using Mrl not only to control and report on system status, but also to provide you insight into how it's been doing over time .. plotted right along side the weather reports :)  in one nice little gui :)