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The canonical documentation of OpenDTU-OnBattery is hosted at https://opendtu-onbattery.net
If you experience specific problems, please check there first! In this community-driven Wiki you may find additional information.
OpenDTU-OnBattery is a fork of OpenDTU by Thomas Basler (tbnobody).
The main idea behind this project is to limit the amount of unused solar energy from small solar installations (in German "Balkonkraftwerke") that is otherwise injected into the electricity network without the user receiving any money.
Instead of giving it away, this unused solar energy can now be stored into a battery for later use.
OpenDTU-OnBattery can also be used without a battery installed: It can dynamically adjust the power output the inverter in order to avoid surplus solar energy being sent to the electricity network.
OpenDTU-OnBattery supports a multitude of battery/battery-charger combinations, always using the HOYMILES inverter series for electricity production.
It will use the information from VICTRON MPPT chargers or dynamically control the HUAWEI R4850 Series rectifiers in order to charge the battery (other forks of this project support other rectifiers as well).
Please keep in mind:
Hoymiles Inverters will work best with 48V/51V LiFePO4 batteries.
Hoymiles Inverters work poorly with 24V batteries (for loads above 250W-300W).
Hoymiles Inverters do not work with 12V batteries.
(illustrative, in reality all inverter Inputs must be connected to the battery)
Zero feed-in (in German: Nulleinspeisung)
With Battery and DC charging via (up to two/three) Victron MPPT
Note: Due to the limitation of most ESP32 boards, you can only use two out of three Victron units, i.e. two Victron MPPTs or one Victron MPPT and a Victron SmartShunt. You can not use two Victron MPPTs and a Victron SmartShunt at the same time. Using a second MPPT will also conflict with the SDM powermeter.
On ESP32-S3-USB boards you can use up to three Victron MPPTs. If three MPPTs are defined in the pin mapping, you will not be able to use the SmartShunt and JK BMS battery interfaces.
With Battery and DC charging via (up to two) Victron MPPT and (optional) Victron SmartShunt (see conditions mentioned above)
With JK BMS, Battery and DC charging via (up to two) Victron MPPT
With Pylontech Battery and DC charging via (up to two) Victron MPPT
With Battery and AC charging via Huawei Rectifier
using the Huawei AC charger in combination with the CMT2300A radio board for HMT- and HMS-inverters is supported as of Firmware Version 2024.09.11
