Limiter inverter with RS485 load setting

completelycharged

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I already have a growatt solar inverter so i am looking for a "battery inverter" which i can control via RS485.
This is the first one i see..
Does anyone know other battery inverters (so only battery connected to it) where the output can be regulated?

The number of units that allow external "user" control of the output are very limited because most country grid codes actually stipulate a requirement for this not to be possible. There are real particular reasons for this but mostly protectionism at this stage because the number of units on the system is very very small.

The GTIL units should be possible to control if the firmware is opened up with the right messaging (waiting for someone to discover the messaging).

SolarRiver inverters are controlable on the output but the response rate is not really much use for load matching and then your reducing solar output, unless your feeding them with 400V DC from an inverter board through a regulating capcitor.

Otherwise I have done many hours research and browsing trying to find the unicorn of a high output capacity, low losses, reversable, user controlable inverter. The closest I got to was to look at disconnecting the grid altogether and mixing a few inverters... and is the plan for 2022.
 
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completelycharged

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@completelycharged In your opinion, it can work for a rs485 wifi adapter on the controller side and rs485 wifi on the inverter side?
Yes, should work ok.
Latency on a wifi link will be fine, reliability may pose an issue if the signal drops out a lot.

One thing to point out is that the target output persists until a new target is given, so if you send 800W and then the link drops the inverter will happily carry on with 800W until the battery low voltage limit is reached.... This makes for a plan to add in a secondary system to allow for disconnection OR have multiple send capability on the RS485 bus.
 

Stefanseiner

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Apr 16, 2020
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Today I connected the powermeter/limiter to an RS485 -> USB to serial converter on Windows and made quick and 'dirty' C# app. It reads the data and shows the watt in the console. I just want to share this code in case someone can use it to get startet or something like that. This powermeter/limiter could be used without the Inverter as a 'Kill A Watt' ... Does anyone know if it's possible to set it as Unit 2 or 3 without the Inverter, I would like to see if the modbus data changes.
This sounds very good :)
Maybe it is the right direction to a 3-phase meassurement for the little SoyoSource
 

alpha60

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Mar 9, 2021
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Hello, would it be possible to send the power that we want manually to the inverter without going through the compeur, for example I ask him for 300w then at another time I ask him for 500w.
 

grundholm

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Oct 3, 2020
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If you connect a battery, then in the menu - you set it to battery mode and then battery start Volt, battery off Volt and the amount of Watt you want to take from your battery and add to the grid. I am currently playing around with an Arduino / ESP8266 - then it will be possible to add some logic.

@Stefanseiner
I now made a little program for an Arduino, it reads the Watt from one meter (and sends the Watt value to Influxdb)
- I think it's possible to add 2 more meters and then add all 3 values and then send the value to the GTIN. I hope the Arduino is fast enough. At the moment i'm waiting for one more meter from China....
 

Stefanseiner

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did you order the whole meter?

I asked several sellers on Ali for a single clamp sensor and one seller did an article specially for me with single clamp sensors
Snipping_007.jpeg



Another way could be to use the clamp sensors from the SUN GTIL and this board
Snipping_010.jpeg


Maybe with 4 sensors and some logic it could be possible to
a) add the current from three phases
b) subtract the current which comes from the inverter because both, the SUN and the SoyoSource can not detect the direction of current and sometimes it is impossible to find a place where you can install the clamps without interfere the inverter
 

grundholm

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Oct 3, 2020
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The board is basically 4x this project: https://learn.openenergymonitor.org...onitor-measuring-current-only?redirected=true

It's necessary to add a voltage meter from each fase to calculate the Watt.

The SOYO expect a (RS485) / serial byte array with the watt value. It's easy to send this from an Arduino.

I ordered the 2nd energy meter, because it's easy to read the serial commands with an Arduino and then send a modified byte array to the SOYO. I know that these meters are not very accurate and doesn't detect current direction. A better solution would be to use the Eastron SDM630 with Modbus - they can detect current both ways.
 
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