Gathering data from Grid Tie system


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Wayne's World

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Joined
Jan 28, 2020
Messages
86
I currently have a grid tie system and I get excellent FIT. My long term goal is to set up a separate off grid system and move all house loads to it and maximise the solar output from the GT system. I'm sure Energex won't like this, but that's the idea. I'll either start with an inverter sized to do the hole house, or use units that can be scaled if that's possible. As I build the system and add battery packs, I'll move loads across. Space is really not an issue. I've got a couple m2 to mount an inverter or 2 and switchboard, and I can build a battery shed at the back of the house. I will also want Grid backup for those times the batteries fail, need maintenance, or are low, or my usage exceeds the system. (so Grid input only to this one). I can't see this contravening local laws.

I'm also considering 3 phase for AC and workshop, so that needs to be part of the design to.

Secondly, its been suggested that eventually these FIT will be reduced substantially, so that's another reason to setup an off-grid system. With that in mind, would be nice to be able to tie in the current GT system to make use of it when that happens. I guess that just becomes the 'grid backup' I've already mentioned.

For a while now, I've been wanting to set up a data logger to monitor what I'm using, generating, and exporting to the grid. I've got a smart meter installed 6 months ago and I can log in to the metering company, but of course I can only see what the meter sees - net power usage from the grid and exported to the grid.

What I would like to monitor is...
- Total DC power generated from each of 2 strings, as they are on different roof faces (Just nice to see what's happening)
- Peak power draw at any given time
- Total AC power generated, and exported vs used

If anyone has suggestions as to what other data might be useful, happy to hear it.

I'm probably a good couple of years away from getting a system online, so now would be a good time to start collecting data, to allow proper design and sizing of the system.

I figure I need some DC and AC clamp readers, a logging system and a data line to my network (easy done), and software to collate and access the data.

I've seen plenty of systems that do some, but not all of these things.

I know what you're thinking... some of that data can be taken straight from the inverter. I have tried this. Its a 6 year old Macsolar and the software is abysmal and I could never get it to work properly. If I could see benefit in upgrading the inverter for data, efficiency gain, more panels, and integration with the future system, I'd consider it. But it has to meet the federal 5kW limit for me to keep the FIT.
 

daromer

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Oct 8, 2016
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5,662
I use SDM630 or SDM120 to meassure current and voltages on AC side. On DC side you can use regular shunt and voltage divider to esp to send the data.
 

Wayne's World

Member
Joined
Jan 28, 2020
Messages
86
I was hoping not to have to go down the Ardunio rabbit hole haha. If I can't get something off the shelf, I might have to I guess.

Can you get these systems to write to an excel spreadsheet?
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,760
Wayne\ said:
I was hoping not to have to go down the Ardunio rabbit hole haha. If I can't get something off the shelf, I might have to I guess.

Can you get these systems to write to an excel spreadsheet?
Off the shelf Iotawatt!

It will export to influxdb my home serverhttp://wolftech.mynetgear.com:4562/...-plant?orgId=1&refresh=5m&from=now-24h&to=nowuser guest password guestw

You can play around in there check out all the dashboards.

emoncmshttps://emoncms.org/dashboard/view?id=53517my dash board

and in your neck of the woods PVoutputhttps://pvoutput.org/list.jsp?userid=74397

T
o get as granular as I have you need to sit down with arduino or ras-pi.

Im sure you can export this info to excel. I know that grafana has that option but why when it can chart it for you.
I do suppose if you want to analysethe numbers excel will be a better choice.
Wolf
 
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