I recently got a solar system installed. As Growatt had reasonable prices and was available, I picked a MOD 10kTL3-XH BP inverter and their APX battery system. I also opted for a so-called Backup Box, the SYN 50-XH-30.

Now I finally got permission to export energy into the grid, before the system only charged the battery for about a month.

When the new energy meter was installed and the old one removed the backup box actually kicked in and provided energy for the house, so this seems to work fine. But I am not sure how long it took to take over, I believe it took a few seconds. Growatt says it should take over within 0.5 seconds.

Ok so now the settings, these are a bit tricky and very badly documented. I had to scour forums to get this working correctly.

I am documenting this for me and anyone else who has trouble.

Only use the cloud web interface to set these settings, the phone app seems to do different things. The password to change and read settings using the web interface is "growatt" plus the current date in YYYYMMDD, so for example "growatt20240211". Oh and switch the language to English. The German translation is very weird and so are probably other languages.

Time Slots

This is very important so the inverter knows which mode to run. Otherwise, it does not default back to a sane default mode.

  • There are 3 modes:
    Load first: This should be the default mode, it provides energy for the house and stores excess solar energy in the battery or exports it if the battery is full. It will use the battery to provide energy to the house if there is not enough sun. This should be the mode you want to use.
  • Battery first: This charges the battery, there is also an option to use the grid to charge it. Not entirely sure what happens when the battery is full, it will probably cover the load but it is also possible it will export energy.
  • Grid first: This will export solar energy and energy which is stored in the battery to the grid.

One needs to define at least 2 time slots, these do not work immediately only when the point in time is reached. Here are my current settings, which are working:


Set this so the inverter knows how much energy is needed. Some people in the forums say it works for them without this setting, but it should not hurt anything.

You obviously need to connect a compatible smart meter for this to work!

Ok, this is it.

With these two settings, the inverter should respect the EMS rules you set. I am still experimenting with mine, but I am currently using these:

This means the battery should be charged as fast as possible till it reaches 100%. It can be discharged at half the possible rate (I will probably set this to 100% soon) and discharging will stop at 15%. The grid will not be used to charge the battery (but the inverter uses it to hold the 15% at night. The battery itself has some losses so it needs about 50W/h to hold the level (this is for me 15kWh setup and will probably be different if yours has more or less capacity).

I also had an export limit activated, but this can probably turned off. At the moment it is still activated and it is set to export 100% to the grid, so if there is excess it will export up to 10KW.

Solar Assistant

This is a nice piece of software that you do not really need, all it can do you can also do with Home Assistant for example or just use the Growatt app or cloud web interface.

It provides a nice web interface and runs in my case on a Raspberry Pi 4. The Raspi is connected directly to the Growatt inverter and collects and stores data locally. It also servers the web interface.

Everything worked flawlessly and shows all the stats in a much nicer way.

You can also use it to configure the EMS settings:

The Solar Assistant team is also working on providing the settings for the time slots, but this is currently not available for the MOD inverters, but it should be soon.