FAQ

Is it possible to have 2 solar panels directly on the HOYMILES and connect the other 2 inputs to the 48v battery system?

No, this is not supported. (we talk about a 4 input, two MPPT version, eg 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 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 MPTTs. So, 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).

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Why is OpenDTU-onBattery only able to manage five inverters (instead of ten)?

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How to change the Max Number of Inverters that OpenDTUonBattery can handle (default is 5)

Have a look here: https://github.com/helgeerbe/OpenDTU-OnBattery/wiki/Compile-your-own-Firmware-with-Visual-Studio-Code#the-most-often-raised-question

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Can OpenDTU-onBattery Dynamic Power Limiter control more than one Inverter?

No ....and Yes, there are solutions:

(to be translated)

Also ich betreibe zwei OpenDTU-OnBattery Steuerungen mit aktiviertem Dynamic Power Limiter (Nulleinspeisung) für zwei 800W Balkonkraftwerte (HM-800) momentan noch ohne Akkus. Das läuft bislang ganz gut und die Regler schwingen sich auch nicht auf. Nur wenn Wolken kommen und oft zwischen Sonne und Schatten wechselt, dann geht die Regelung ab.

Ich habe es genau so gemacht. Jeder WR wird von einer DTU gesteuert. Ich habe allerdings bei mir jeweils eine DTU auf L1 und L2, (diese 2 Phasen machen den Löwenanteil an dauerlast aus) und lasse die jeweilige DTU auch nur diese Phase im Shelly3EM sehen (/emeter/0 und /emeter/1), vielleicht ist das ja eine Moeglichkeit, ungewollte Schwingereien zu unterbinden.

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Can OpenDTU-onBattery handle the information of multiple Victron MPPTs?

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Do I need separate Victron MPPTs if I place my Solar Panels in different directions? (the infamous East/West Question)

No. And you do not need (to have separate Victron MPPTs for each direction).

For more information: https://github.com/helgeerbe/OpenDTU-OnBattery/wiki/Victron-MPPT-battery-charger#east--west--panels-with-only-one-victron

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