Hi Zooka,
this is what I get in openhab.log
[21:43:57] root@openhab:/var/log/openhab2# tail -f openhab.log
2019-11-15 21:43:57.698 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:43:57.701 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 32.375999450683594}' not supported by type 'NumberValue'
2019-11-15 21:43:57.704 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:43:57.707 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 53.959999084472656}' not supported by type 'NumberValue'
2019-11-15 21:43:59.703 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:43:59.706 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 32.411998748779297}' not supported by type 'NumberValue'
2019-11-15 21:43:59.710 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:43:59.713 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 54.020000457763672}' not supported by type 'NumberValue'
2019-11-15 21:43:59.717 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:43:59.720 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 2104}' not supported by type 'NumberValue'
2019-11-15 21:44:01.703 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:01.708 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 32.369998931884766}' not supported by type 'NumberValue'
2019-11-15 21:44:01.713 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:01.716 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 53.950000762939453}' not supported by type 'NumberValue'
2019-11-15 21:44:01.720 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:01.723 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 2108}' not supported by type 'NumberValue'
2019-11-15 21:44:03.705 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:03.709 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 32.453998565673828}' not supported by type 'NumberValue'
2019-11-15 21:44:03.713 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:03.716 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 54.090000152587891}' not supported by type 'NumberValue'
2019-11-15 21:44:03.720 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:03.724 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 0.60000002384185791}' not supported by type 'NumberValue'
2019-11-15 21:44:03.727 [WARN ] [l.generic.ChannelStateTransformation] - Transformation service JSONPATH for pattern $.value not found!
2019-11-15 21:44:03.731 [WARN ] [eneric.internal.generic.ChannelState] - Incoming payload '{"value": 2109}' not supported by type 'NumberValue'
And this is my events.log
2019-11-15 21:41:29.545 [hingStatusInfoChangedEvent] - 'mqtt:broker:ccgx_mqtt' changed from OFFLINE to ONLINE
2019-11-15 21:41:29.572 [hingStatusInfoChangedEvent] - 'mqtt:topic:ccgx_mqtt:solar' changed from UNINITIALIZED (BRIDGE_UNINITIALIZED) to INITIALIZING
2019-11-15 21:41:29.734 [hingStatusInfoChangedEvent] - 'mqtt:topic:ccgx_mqtt:solar' changed from INITIALIZING to ONLINE
2019-11-15 21:41:29.809 [vent.ItemStateChangedEvent] - PV_battery_voltage changed from NULL to UNDEF
2019-11-15 21:41:29.816 [vent.ItemStateChangedEvent] - PV_soc changed from NULL to UNDEF
2019-11-15 21:41:29.826 [vent.ItemStateChangedEvent] - PV_generator changed from NULL to UNDEF
2019-11-15 21:41:29.835 [vent.ItemStateChangedEvent] - PV_battery_current changed from NULL to UNDEF
2019-11-15 21:41:29.837 [vent.ItemStateChangedEvent] - PV_today_yield changed from NULL to UNDEF
2019-11-15 21:41:29.840 [vent.ItemStateChangedEvent] - PV_battery_power changed from NULL to UNDEF
2019-11-15 21:41:29.854 [vent.ItemStateChangedEvent] - PV_total_yield changed from NULL to UNDEF
2019-11-15 21:41:29.857 [vent.ItemStateChangedEvent] - PV_power changed from NULL to UNDEF
2019-11-15 21:41:29.861 [vent.ItemStateChangedEvent] - PV_ac_consumption changed from NULL to UNDEF
Thanks for your help!