Inverter reports total output, not jus PV output

Questions
#1

I’d love to contribute here but have examined the app data, inverter data and the data sent to the server via the app it seems as though our Solax inverter doesn’t report the yield from our panels. Instead, it reports the energy coming out of the inverter as opposed to the energy going into the inverter from the panels. Is this the case with all inverters??

It would be fine if the inverter were only connected to the PV panels but we have a battery as well. This time of year we force charge the battery overnight whilst on a cheaper tariff. So, when we use energy from the battery the inverter reports that as yield in addition to anything coming from the PV panels. This means there is no way of knowing how much the panels on their own are producing.

Is this the way all inverters work? Surely the yield should be just the energy going into the inverter from the PV panels, but I guess as that is DC rather than AC it can’t be measured in the same way??

#2

Hi Justal,
yes all inverters just report the AC output , not the DC input, you need a smart meter to tell what the battery’s are putting in to your house, and to report this to PV output.
Jim

#3

Hi @justal
I posted this on another thread and wondered if you had seen it, Hope this is not considered bad cross posting
Yes I know exactly what you mean and agree with you totally, I think its a Solax oversight to call it yield, I had the same problem. It seems wrong that the yield includes the power that you have put into the battery overnight. The way I get round this is to read the PV1P and PV2P output (I have 2 strings of panels) using a Raspberry Pi to get the data from the inverter. This data is then fed into a Node Red flow to convert to kWh and upload to PVoutput. You can see the results here Bens Solar Power 5.400kW
Its all a bit of a pain and not really worth the effort but if you are already extracting the data from your inverter locally its not much more work. I would be interested to see you site on PVOutput, always great to talk to a fellow Solax owner

#4

That sounds cool - I’m not extracting the data locally (yet) so it might be too much trouble. What I’m doing is writing a WordPress plug-in that uses the Solax API to get the JSON file from the Solax server and then inserts that into a MySQL database so that I can display some of the data within my website.

PVoutput is probably a better option but I’ve started this now and it’s only a bit of fun so I’ll keep working on it. I’ve been using the dc1power for the live output as well. As far as yield is concerned I make a calculation that uses the ‘yield’ figure from Solax but (if force charging is on) subtracts the ‘yield’ from the battery from that figure. The ‘yield’ from the battery is itself based on the percentage of battery used that day.

It’s a work in progress but you can see what I’ve built so far here: https://www.alananna.co.uk/blog/solar-generation/

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#5

Hi @justal. I have had a look at your site, it is really nice. Your Solax installation is also really neat.
If you would like to get instant readings from your inverter you can get the data by using Modbus. You poll every few seconds and a whold load of data comes back, again I use Node Red to do this and feed to an old Ipad which is now on a stand in the kitchen.

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Are you using your EPS output ?. We don’t have many power cuts but just in case I have wired the EPS output to a changeover switch so in the case of a power cut I can power the house from the battery. (up to 4kW
Keep up the good work.

#6

If anybody is interested in using Modbus with Solax Hybrid I have done a very boring and unprofessional Youtube video on how to use Modbus, you do need some experience with a Pi and Node Red but there are loads of videos on how to setup a Pi and NR. Solax Hybrid Modbus setup part 1 - YouTube
or search solax modbus

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