Hi folks,
First post and wondering if anyone can help.
I have a remote circuit about 50m away from my inverter that feeds my shed and I use forced discharge to cancel out its usage.
I have an automation that takes house load + shed load and adjusts forced discharge output every few minutes. During the day when solar is producing and battery SOC <100% it's all fine. Solar charges batteries, powers house and excess is pushed to the grid etc.
Once the batteries hit 100% SOC as I am still using forced discharge, the solar PV reporting drops to the forced discharge power. Obviously at this point I would like the excess solar to back to the grid, but I can't monitor the PV generation as the figure is wrong.
I have modbus connection to the inverter, is there any way to get actual PV production when in forced discharge or does the inverter sensors only see the restricted values for reporting purposes?
I know i can switch to self use at 100% SOC and rely on solar to cover the shed, but factoring in low solar (clouds etc) will mean a lot more complicated automation. The only other option is remote smart meter to monitor the shed but that will be a while off yet.
Thanks
J
First of all, welcome!
Not sure if I have the wrong end of the stick, but is your CT clamp in the wrong place?
Typically it would be after the meter, so that it can monitor your entire house load, meaning it should measure your home load and your shed load, and react accordingly?
Not sure if I have the wrong end of the stick, but is your CT clamp in the wrong place?
Typically it would be after the meter, so that it can monitor your entire house load, meaning it should measure your home load and your shed load, and react accordingly?
Thanks for the response but unfortunately it's not that simple.
I have 3 switchboards, the main one that is about 50m away from the house, a second one in the house and a third one in the shed (20m away from house).
I have 2 single phases (odd i know) from the provider to the main switchboard, both phases then go to the house but one of them is split at the main switchboard and goes to the shed.
I have 2 single phase inverters with 2 battery stacks and the CTs that monitor the 2 phases at the house - I can't put the equipment at the main switchboard as it's just on a pole at the entrance in the front garden. I also can't run a phase from the house to the shed as the cables to the house are only 6mm.
To monitor the shed load I have a shelly pro and i feed all the loads into Home Assistant and have a Node Red automation that calculates total load across the house and shed every minute and does a forced discharge calculation on both inverters to cover it. This covers the house loads and forces some feed-in to net cancel out the usage at the shed.
This all works fine and covers usage and charges the batteries from solar etc. the only issue is that once the batteries hit 100% SOC the excess solar is dropped as the forced discharge limits the PV production to the forced discharge power. This would be fine if i could read the actual PV generation values but they seem to be clipped to the forced discharge power values rather than reporting the actual generation.
I was wondering if there was any way to get the true PV output via a register or similar so that i could update the forced discharge to include the PV generation and push it back to the grid (i have RS485 for monitoring).
Ultimately I will probably need to add a smart meter at the main switchboard and modbus the usage back to the inverters but that will be some time away yet.
Thanks
J
I have 3 switchboards, the main one that is about 50m away from the house, a second one in the house and a third one in the shed (20m away from house).
I have 2 single phases (odd i know) from the provider to the main switchboard, both phases then go to the house but one of them is split at the main switchboard and goes to the shed.
I have 2 single phase inverters with 2 battery stacks and the CTs that monitor the 2 phases at the house - I can't put the equipment at the main switchboard as it's just on a pole at the entrance in the front garden. I also can't run a phase from the house to the shed as the cables to the house are only 6mm.
To monitor the shed load I have a shelly pro and i feed all the loads into Home Assistant and have a Node Red automation that calculates total load across the house and shed every minute and does a forced discharge calculation on both inverters to cover it. This covers the house loads and forces some feed-in to net cancel out the usage at the shed.
This all works fine and covers usage and charges the batteries from solar etc. the only issue is that once the batteries hit 100% SOC the excess solar is dropped as the forced discharge limits the PV production to the forced discharge power. This would be fine if i could read the actual PV generation values but they seem to be clipped to the forced discharge power values rather than reporting the actual generation.
I was wondering if there was any way to get the true PV output via a register or similar so that i could update the forced discharge to include the PV generation and push it back to the grid (i have RS485 for monitoring).
Ultimately I will probably need to add a smart meter at the main switchboard and modbus the usage back to the inverters but that will be some time away yet.
Thanks
J
I can see that you don't have a standard setup. I have heard of using only two phases, makes it more of a spicy post is all 
It might be worth fleshing out some more details of your two inverters, and how they are wired up.
PV to one/both?
Are the two inverters linked to act as one?
Model details?
Firmware versions?
I doubt I can help out too much, but the extra details can help the more technical members for sure.
It might be worth fleshing out some more details of your two inverters, and how they are wired up.
PV to one/both?
Are the two inverters linked to act as one?
Model details?
Firmware versions?
I doubt I can help out too much, but the extra details can help the more technical members for sure.
2x H1-5.0-E-G2 all on latest firmware.
They are separate inverters with a phase going to each one. PV string on each one also. 2x battery stacks a 15 and 17 each connected to an inverter.
The setup is fine and everything works as expected, the only issue I have is that PV output is restricted when using forced discharge.
I presume this is known and by design, however I was wondering if there is a way to report actual PV output rather than the restricted PV output that is reported due to the forced discharge power setting.
The reason why i want the actual PV output is so that i can work out when PV is greater than total loads (including shed) and i can switch to self use.
As i mentioned before I use forced discharge to negate the use of a remote phase which is fine if there is no PV and i'm running from batteries. But if there is batteries are 100% and there is PV available and it is greater than the house and shed loads then it would be better to run in Self Use mode as this pushes all the extra PV to the grid whereas in forced discharge it would only push the house and shed loads towards the grid cancelling out the usage.
John
They are separate inverters with a phase going to each one. PV string on each one also. 2x battery stacks a 15 and 17 each connected to an inverter.
The setup is fine and everything works as expected, the only issue I have is that PV output is restricted when using forced discharge.
I presume this is known and by design, however I was wondering if there is a way to report actual PV output rather than the restricted PV output that is reported due to the forced discharge power setting.
The reason why i want the actual PV output is so that i can work out when PV is greater than total loads (including shed) and i can switch to self use.
As i mentioned before I use forced discharge to negate the use of a remote phase which is fine if there is no PV and i'm running from batteries. But if there is batteries are 100% and there is PV available and it is greater than the house and shed loads then it would be better to run in Self Use mode as this pushes all the extra PV to the grid whereas in forced discharge it would only push the house and shed loads towards the grid cancelling out the usage.
John