I thought I'd write this to collect the information I have found in one place in case it can be useful to others.
There's a lot of odd gotchas with the Deye inverter firmware and a few positive surprises.
Integration:
Thanks to the network dongle used by Deye the inverter can be accessible locally at the same time as it is registered and providing data to their Deye Cloud. This allows very easy integration to Home Assistant thanks to Solarman integration by David Rapan and his band of merry contributors!
The current version supports as good as all aspects of the configuration as well as live data for all trackable values. It is literally super.
Monitoring/Sensing:
The inverters support it's built in CTs on load port as well as external CTs (Supplied with all hybrid inverters) for monitoring grid connection.
Unfortunately this is where there's a major gotcha. Unless in "Zero Export to CT" mode the unit will not sum up and count the power consumption to home loads (if using load port just for backup loads) and will not be able to do any peak shaving. It can also not regulate battery discharge to cancel out home load. It can however do fixed rate discharging and it can report the grid flow via "External CT?" Power/Current type metered values as well as a "External Power" value to sum it up. Charging and discharging battery is then blind.
Limitations:
Deye is open about this but it is not easy to understand: The specifications (power rating) are based on a specific voltage on grid connection and using lower voltages derates your output. Using a TN-grid rated inverter on IT-grid for example reduces it's AC power output by 40% due to the voltage change from 230v L-N to 133v L-N. This does not reduce the solar input capabilities of the MPPTs nor the battery charge/discharge power, but managing this to utilize it fully is not easy.
Another oddity is the balancing of phase-currents. The option "Asymmetric phase feeding" does no thing from my testing on firmware HMI:0-1001-c050 / MAIN:2005-1172-1807. This means the inverter can get into real trouble trying to balance higher current imbalances than it's rating and there are no logs or warnings that this is happening. The inverter will reset it's solar production momentarily and ramp back up. This only happens in modes using the external CTs, so not in "Selling First" where CTs are ignored. In this mode output is balanced. (This of course only applies for 3-phase inverters.)
TOU (Time Of Use):
There is some interesting aspects to the settings in TOU as well. In %-mode the state of charge settings in TOU seem to guide when discharge of battery is allowed to meet load demand. If the setting is higher than current SOC then a dropout from solar, for example from a cloud, will cause power to be drawn from grid to meet demand. It also does not control charging maximum. If there is surplus solar the battery will be charged to 100% regardless of the TOU interval setting. Setting an interval to 100% seem to only be useful if you are forcing it to charge from grid (remember to tick the box) as it will stop charging at the requested SOC in this case.
Taming the beast:
I have found that as long as there is capacity in battery to receive power the inverter will charge the battery with any excess solar before exporting it. By preventing battery from charging fully while the inverter can handle the power one can force the inverter to charge the battery with energy that would otherwise be clipped. This can be done by letting HA control the max charging amps value! It can be set all the way to 0 to stop any charging.
Controlling this parameter appears viable for regulating charging.
When it comes to discharging/exporting I have not found any way yet. Unfortunately the "Zero export power" is not allowed to be negative or this would have been a way to introduce export in a quite nice way. (Deye please implement this?)
Sidenote:
When using V-Mode for battery the inverter appears to taper down discharge current as it approaches low battery voltage. This leads to the value being set acting as Voc (Open circuit voltage) not Vl (Voltage under load). Worth knowing to avoid over-discharging battery.
In %-Mode this does not appear to happen the same way and basic discharge is cut when low voltage is hit. However the inverter will power itself from battery instead of grid until battery is at shutdown voltage which is worth remembering. Especially if overriding charging current.
If anyone has any trics/tips or hacks to add to this, please do so!
There's a lot of odd gotchas with the Deye inverter firmware and a few positive surprises.
Integration:
Thanks to the network dongle used by Deye the inverter can be accessible locally at the same time as it is registered and providing data to their Deye Cloud. This allows very easy integration to Home Assistant thanks to Solarman integration by David Rapan and his band of merry contributors!
The current version supports as good as all aspects of the configuration as well as live data for all trackable values. It is literally super.
Monitoring/Sensing:
The inverters support it's built in CTs on load port as well as external CTs (Supplied with all hybrid inverters) for monitoring grid connection.
Unfortunately this is where there's a major gotcha. Unless in "Zero Export to CT" mode the unit will not sum up and count the power consumption to home loads (if using load port just for backup loads) and will not be able to do any peak shaving. It can also not regulate battery discharge to cancel out home load. It can however do fixed rate discharging and it can report the grid flow via "External CT?" Power/Current type metered values as well as a "External Power" value to sum it up. Charging and discharging battery is then blind.
Limitations:
Deye is open about this but it is not easy to understand: The specifications (power rating) are based on a specific voltage on grid connection and using lower voltages derates your output. Using a TN-grid rated inverter on IT-grid for example reduces it's AC power output by 40% due to the voltage change from 230v L-N to 133v L-N. This does not reduce the solar input capabilities of the MPPTs nor the battery charge/discharge power, but managing this to utilize it fully is not easy.
Another oddity is the balancing of phase-currents. The option "Asymmetric phase feeding" does no thing from my testing on firmware HMI:0-1001-c050 / MAIN:2005-1172-1807. This means the inverter can get into real trouble trying to balance higher current imbalances than it's rating and there are no logs or warnings that this is happening. The inverter will reset it's solar production momentarily and ramp back up. This only happens in modes using the external CTs, so not in "Selling First" where CTs are ignored. In this mode output is balanced. (This of course only applies for 3-phase inverters.)
TOU (Time Of Use):
There is some interesting aspects to the settings in TOU as well. In %-mode the state of charge settings in TOU seem to guide when discharge of battery is allowed to meet load demand. If the setting is higher than current SOC then a dropout from solar, for example from a cloud, will cause power to be drawn from grid to meet demand. It also does not control charging maximum. If there is surplus solar the battery will be charged to 100% regardless of the TOU interval setting. Setting an interval to 100% seem to only be useful if you are forcing it to charge from grid (remember to tick the box) as it will stop charging at the requested SOC in this case.
Taming the beast:
I have found that as long as there is capacity in battery to receive power the inverter will charge the battery with any excess solar before exporting it. By preventing battery from charging fully while the inverter can handle the power one can force the inverter to charge the battery with energy that would otherwise be clipped. This can be done by letting HA control the max charging amps value! It can be set all the way to 0 to stop any charging.
Controlling this parameter appears viable for regulating charging.
When it comes to discharging/exporting I have not found any way yet. Unfortunately the "Zero export power" is not allowed to be negative or this would have been a way to introduce export in a quite nice way. (Deye please implement this?)
Sidenote:
When using V-Mode for battery the inverter appears to taper down discharge current as it approaches low battery voltage. This leads to the value being set acting as Voc (Open circuit voltage) not Vl (Voltage under load). Worth knowing to avoid over-discharging battery.
In %-Mode this does not appear to happen the same way and basic discharge is cut when low voltage is hit. However the inverter will power itself from battery instead of grid until battery is at shutdown voltage which is worth remembering. Especially if overriding charging current.
If anyone has any trics/tips or hacks to add to this, please do so!
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