Dynamic Power Limiter

Canonical Documentaton

Please also consult the documenation.

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HomeAssistant Toggle Switch

You can activate/deactivate the Dynamic Power Limiter by writing a value ("0", "1" or "2") from your Home Automation System using MQTT. Read the complete information and details at MQTT power-limiter-topics.

This toggle is auto-discoverable using Releases more recent than 2024-03-17.

How does the Hoymiles Inverter handle the calculated Power Limit

Used to be part of the Q&A but we feel it deserves a more prominent position. We often see discussions in the forum where people are ready to experiment with a variaty of hardware combinations.
Is it possible to have 2 solar panels directly on the HOYMILES and connect the other 2 inputs to the 48v battery system?
No, combinations are not supported. For example, a 4 Input, two MPPT version like the HM-1500, the HOYMILES in this setup will only "coincidentally" cover your household consumption exactly when the solar panels can provide enough power.
At night however, this will not work because only about 50% of the power limit can be reached (two inputs out of four are used)
The set limit to the HOYMILES applies to the sum of all MPPTs (i.e. all inputs).
This means is, on a four input system with two MPPTs, any given limit will be split equally among two MPPTs.
e.g. a limit of 400W set, HOYMILES HM-1200/1500 will expect 200W from each of the two MPPTs.
Subsequently, at night when only one MPPT (two inputs) is connected to the battery, 400W/2=200W is delivered although the set limit is 400W.
The limit is then probably adjust itself and gradually/possibly(?) might still somehow get there, but honestly, we would strongly advise against it.
Keep in mind, above applies when you connect the two panels to one MPPT, and the battery to the other MPTT (HM-1500 has two MPTTs each handling two inputs).

Actually, OpenDTUonBattery is a bit more advanced:
It has an embeded algorithm trying to estimate the number of active inputs and "scale" the commands given to the inverter.
"Scaling" works only for inverters which have one MPTT pro Input (e.g. HM-800 and HMS-1600 models).
Inverters whose MPPTs control more than one Input (e.g. HM-1500 with two MPPTs for four Inputs) cannot be scaled for the time being.

• Prerequisite #1: The total power of the inverter is higher than the number of Inputs times 10. e.g. HM-800 (two MPPTs/two Inputs) 2x10=20W, HMS-1600 (four MPPTs/four Inputs) 4x10=40W
• Prerequisite #2: Only the Inputs that deliver more than 2W will be taken into account.
  Based on the above conditions, OpenDTUonBattery will scale the limit appropriately.

What is the fastest/most accurate Dynamic Power Limiter setup?

• One inverter only
• latest OpenDTU-OnBattery Firmware installed
• power meter polling interval at 1 second or even better MQTT power meter interface where the values are published once a second (faster power meters are not really available, AFAIK),
• DTU polling interval set to 1 second
• Also, the wireless connection to your inverer must be good, i.e., not too far away, not too close, little packet drop.
  See if the data age in the live view is often larger than 1 second when the DTU interval is 1s, then it should only ever be 1s in the ideal case. Then you can expect your inverter to react in the range of 2 to 3 seconds.