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Solar Power monitoring cost does not make sense


bushman10
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Having dabbled a bit now in the development of such software and hardware ... I have a theory:

When you think of all the ways end users would want to connect and read the data, you need a rock sold reader, with options.
To have the data hosted, no matter where it is on the web, has data and server space costs attached.
To develop the software to view the data accurately and nicely, costs.

And no-one wants to pay for it ... as we have debated here on the forum on previous occasions.

So the manufacturers, I think, are building all the above hardware RD, software RD and hosting costs into the price of their devices to be able to do the above for you for "free" for as long as the equipment could last, which in Schneider's case, is wot, 15-30 years?

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You guys want to watch this... which is why I keep harping on doing this in some sort of open source way. There is a reason why nobody wants to pay for this sort of thing. You will need time to watch this, but you should:

 

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In looking at options to monitor both the Victron and the Schneiders I have come accross a product called the Solar-Log 1200 at www.solar-log.co.za. The website says that it can link to ALL inverters but in checking this fact with a local suplier they state the following:

"Victron is one of a handful of inverters that uses RS232 protocol. The rest all use either RS422 or RS485. Solar-Log wanted its product to be compatible with the biggest range of inverters and thus went for RS422/485 combination. Imeon, for instance has recently changed their inverter from RS232 to RS485 to fall into what seems to becoming the industry standard for inverters".

Any Comment?

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Victron uses RS232? Well, maybe they confuse the names, because I think the only piece of equipment that uses that is the older mk2 serial unit, most people now use the mk2-usb. They have some other deprecated protocols (an RS485 protocol on the older Phoenix inverters, and VE-Net), and there is the internal protocol between inverters (ve-bus) that you are not supposed to mess with (it's like BMW's K-BUS... only for internal use). Currently only three protocols are used for 3rd party connectivity, 1) can bus (nmea2000, for interfacing with marine equipment), 2) ve-direct (which is TTL-level serial, not RS232), and mk2 (which is usually usb now).

So strictly speaking that is not quite true, though at the same time, I think they broad implication is that when people say they support "all" inverters, they really mean "almost all" inverters.

However, there is a standard that is becoming industry standard, known as sunspec. Sunspec is usually layered on top of modbus, layered on RS485 (RTU iow), and this is supported by many inverters (at least SMA and Fronius as far as I know, as well as some Lithium battery BMS systems). I have a feeling those Schneiders might even support that.

As a programmer, I'm a little amused when people worry about can vs rs485 vs rs232... those are layer 1 and layer 2 things (assuming 7-layer OSI model). The difficult parts, the parts that cost time and money, are layer 3 and up.

On the software side, we end up with a "character device", something that spits out sequential data if you open it and read it like a file, but cannot be forwarded and rewinded (randomly seeked) like a file. It literally all looks the same from the software side. If you plug in an RS485 converter, an Victron MK2, a Victron VE-Direct, they will all show up as "serial ports" on the OS side. On Linux, the can bus shows up as either a network device or a serial device, depending on hardware.

Also, RS485 is also just serial, the difference lying in using differential signalling, which allows longer distances. The data on top of it, again, is the real hard work. I would think that if this is the stumbling block, then adding a RS232->RS485 converter should solve it... but of course it won't, the issues are deeper :-)

Edit: Can't reveal names just yet, but I have heard on the grape vine that a supplier of Lithium Ion batteries is switching its BMS from RS485+Modbus to a canbus solution... once again calling question if there really is an "industry standard" :-)

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@bushman10 When it comes to monitoring there is more than one way to skin a cat. It all boils down to what you what to achieve.

Some thing to consider: If you only want to monitor the inverter's performance you do not have to do it by directly connecting to the inverter. All you need to do is to monitor its inputs and outputs. For example let assume you have a hybrid inverter with batteries, grid connection, PV panels and a load output. All you need to do is to monitor the volts/amps from the PV, the Volts/Amps to and from the battery bank and the Volts/Amps on the grid input and output. There are various ways to do this. Also, it does not matter which make or model of inverter it is, this approach will work for all of them.  Have a look at http://www.exsolar.co.za/products/monitoring-devices/advanced-energy-monitor-exsolar-em502/(Thanks Cobus for the link)

The only reason you would want to connect to the inverter directly is if you want to change the behaviour of the inverter in some way or another or if you want to monitor some internal state in the inverter. If this is the case you have have a connection to the inverter (RSxxx or USB) and use software. 

 

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27 minutes ago, Janma said:

you do not have to do it by directly connecting to the inverter

Indeed, I know people who do makeshift monitoring with two Efergy clamp monitors on the input and output. Of course it isn't perfect, by now I'm sure everyone knows of the problem with power factor... but for about R500 or so... that is probably the cheapest thing you can do (and I believe the modern ones have USB connectivity too).

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28 minutes ago, plonkster said:

and I believe the modern ones have USB connectivity too

I use the Efergy hub (will change it as soon as the piggy bank is not empty anymore). The data is hosted in the cloud, you get a web interface to a dashboard and you get a cell phone app. You can download the data in CVS format if you want to. Both the Web and Cell phone apps can be used to display real time and historical data. Its quick to install, easy to use but not 100% accurate. It can not monitor DC so no way to monitor your batteries or PV. 

Another option is OpenEngergy monitor https://openenergymonitor.org/emon It can monitor Power factor. No DC though but you can build it in if you want.

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31 minutes ago, Janma said:

no way to monitor your batteries or PV. 

In Bushmen's case, the PV comes in from the Schneider GTIs though, so an Efergy on those line(s) will tell you how much PV is coming in. Victron also sells a Current Transformer that is to be used for this:

https://www.victronenergy.com/accessories/ac-current-sensor

But part of the problem here is simply that to do this properly with commercially available equipment just costs too much. I mean, if you were to do this with what I consider to be the flagship solution (Victron CCGX, BMV, current transformers) you'll be 10k in the red before you've even made it to the third item on that list. Us hobbyists can of course do it much cheaper... but do you feel comfortable selling your cheap solution to a non-technical person, and supporting it indefinitely? There is a reason why people like us refuse to work on computers belonging to family members... :-P

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2 hours ago, plonkster said:

Us hobbyists can of course do it much cheaper but do you feel comfortable selling your cheap solution to a non-technical person, and supporting it indefinitely?

Could not have put it so succinctly myself.

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4 hours ago, Janma said:

The only reason you would want to connect to the inverter directly is if you want to change the behaviour of the inverter in some way or another or if you want to monitor some internal state in the inverter.

And a third reason is because you want to read all the device can provide, from RAM values, to store that and build a history of said devices values. :)

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3 hours ago, plonkster said:

Us hobbyists can of course do it much cheaper... but do you feel comfortable selling your cheap solution to a non-technical person, and supporting it indefinitely? There is a reason why people like us refuse to work on computers belonging to family members... :-P

Spot-on Plonkster. One can do it cheaper in monetary terms (if you have the skill which some of us do) but it takes time. That time has a monetary value to it as well. How much is your time worth?

Some years back I put in leave to do some renovation at home. Mostly painting etc. My mentor at the time asked me why I did not get painters in to do it for me. I told him I could do it a lot cheaper than the quotes I got. He asked me do calculate my "real" cost by dividing my monthly salary by the number of hours I work per month. Then multiply that by the number of hours I spend painting then add the cost of the paint etc.  When looking at it this way it sometimes turns out cheaper to to just get a painter to do it..

Building your own product takes time. Then if you give or sell your product to someone and you are expected to support it, it also consumes your time. All that has a cost. Doing things yourself is not always cheaper.

On the other hand, if what you want does not exist, or you have time and you want to do it as a hobby or to learn something new you could justify doing it. At least you get some enjoyment and a sense of achievement out of it.  If you have to support it afterwards, well, it becomes work...

I must say I take my hat off to the guys on the forum that take the time to build their own software, test it, enhance it etc.

 

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3 hours ago, Janma said:

Some years back I put in leave to do some renovation at home. Mostly painting etc. My mentor at the time asked me why I did not get painters in to do it for me. I told him I could do it a lot cheaper than the quotes I got. He asked me do calculate my "real" cost by dividing my monthly salary by the number of hours I work per month. Then multiply that by the number of hours I spend painting then add the cost of the paint etc.  When looking at it this way it sometimes turns out cheaper to to just get a painter to do it..

On that topic... it introduces a kind of tax gap, something that actually makes a good argument for lower taxes in the middle classes. You see, the hourly rate you work with here is calculated after income tax, because you pay these handymen, painters, and other providers with money that has already been taxed (unless it's for your own business). That bracket is an interesting one, it often means that before tax it would have made sense to pay someone else, but after tax it is cheaper to do it yourself. Especially, given that a good tradesman just won't work for those low rates, I often turn out to be the most economical choice.

This is why I service my own car, but paid someone else to paint my house.

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Glad there are devices out there that can do the monitoring for the device we have. Good then we don't have to develop software anymore.We can use that hours spended on developing by doing other useful goodies :D 

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48 minutes ago, Manie said:

Glad there are devices out there that can do the monitoring for the device we have. Good then we don't have to develop software anymore.We can use that hours spended on developing by doing other useful goodies :D 

BWAHAHAHAHAHAHAHA ... Well said!!!

I think Manie, only once you have had the equipment for a while and realise one day that hey, wait, why is this happening or you now want to add and do more, that is when you want to go further. ;)

Every GOOD solar device has a port of some sort that gives data. 
Every manufacturer has develop software for their devices. Some has gone one step further and provides free web access.

But NONE of the above was for done "free", initially and today some got clever, due to costs, and started to make their software open source. ;)

Yet, when you have to read more than one manufacturers equipment ... that gets real interesting real fast on ones pocket. Been there, done that.

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wonder how many of these devices software can upload there data to emoncms or pvoutput or to join a group like SA Solar output ? Seems there is always a benefit of developing your own software where you can control everything you want to, like starting devices when x happen. Well for me anyway, i am never ever satisfied with the software from manufactures. :D   Even the software that came with the Infini. It is so incomplete for me, no wander people start developing there own software. 

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Came across this video. It's long and it is about Linux, but there are some things to it that I think applies here as well: That whole thing that sometimes when you reinvent the wheel instead of collaborating, you end up making stuff that are really cool!

(oh, and yes, I know the pain of systemd... it is kinda cool that someone took the pain of the hackyness of SysV and tried to solve it... and ended up replacing it with a different kind of pain :-) )

 

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Saw this video yesterday ... but did not have the inclination to post if, in fear of a long debate ... but now Plonkster did it. :P

This guy resonated with my experiences re Linux and all the damn Distro's.

See, I tried to install a version of Ubuntu on a OLD laptop, free software and all ... after a lot of attempts, only to learn that the laptop was to old, yet Windows 7 worked on it! So to try and figure out what version to get ... after a few hours I lost it. So I asked. Was advised to use Feodora, worked, so I wanted to add a piece of software ... no download and install, oh no, Ms DOS style i.e commands, and there where line upon line upon line of commands you have to type in with the inevitable: If it does not work ... inbetween.

Exact same software available for Windows (laptop screen card to old so I could not do it on Windows), download and install - done!

Laptop has been reformatted.

So during this time I was haggled about it all, Powershell being named as a point of debate. 

My response:
Ms DOS released August 1981
Linux  released 25 August 1991 - 10 YEARS later.
Today Ms Dos is all but gone, replaced by user friendly easy to use GUI, working on a LOT of devices out there, Powershell OPTIONAL, rarely used by end users, if ever.
Linux ... GUI installs are rare, mostly not available with too many flavours of Linux.

Note: Do NOT, if you are a Linux expert, try and defend Linux here. I will not listen. :D
Just do yourself a favour and compare a end user who for the first time must install software on Linux vs on Windows, having to talk them though on the phone. 

My view on Linux:
Linux is for the poor IT guys who does not have money, but wants software, or has the brains to develop his own version, for free.
Linux for the rest is only for people who have money to pay the IT guy who does not have money. :P

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You didn't watch the whole video did you? :-)

Only thing that I disliked about the video, is he kept mispronouncing Ubuntu. He might get a smack if he says "ooBantu" in the wrong neighbourhood!

His point is, yes... we do reinvent the wheel numerous time and build horrible monolithic things... but, what if back in the day people looked at KDE and said: I'm not going to build Gnome... I don't want to reinvent the wheel. Well... then we would not have had Gnome, and that would have been a terrible loss. If you look at it from a different angle, sometimes it is good that we reinvent the wheel.

I think another thing people miss, is that when KDE and gnome were having a semi-friendly little banter in the early naughties, one used DCop and the other used Corba for IPC. Today, both use Dbus. They actually managed to standardise some stuff out of the various code paths. They could use the best ideas and make something new.

That is to say, I posted this not to diss or promote any OS. I posted this to say we should stop complaining about the lack of collaboration :-) Perhaps that is actually cool...

I will just say this: That when people compare Linux to MS-DOS (because a unix shell looks like a dos prompt to the untrained eye), they have no idea what they are talking about. Linux came about ten years later for one reason: Because MS-DOS was a horrible waste of an 80386.

I hate it when people say... Linux is difficult to install, therefore Windows is better. The end user might think that, but he'd be wrong ;-)

Edit: Come to think of it, your argument is even worse than that. You're saying the install is "ugly" (not a gui). Thinking of all the OSes I've installed over the years, windows is the only one that does the gui thing. FreeBSD, OS/2, Irix... all have a large textual part to the install. Windows may do a gui, but it is basic Vesa graphics. Pfffft.

Then again, maybe you need a beautiful install because you're going to see it so often... :-P

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