This is v2 of the configuration. The main difference is that it is
mostly backward compatible to the old smartlogger configuration. The
only change is that it is now using register 40521 (active power without
battery discharge) instead of 40525 (active power including battery
discharge).
The grid information comes from the powermeter which has usually the
unit id 11. The pv informations come directly from smartlogger (unit id
0, hardcoded). The battery information is fetched from the hybrid inverter.
A typical configuration should look like this:
```
meters:
- name: grid
type: template
template: huawei-smartlogger
usage: grid
id: 11
host: host.fqdn
port: 502
- name: pv
type: template
template: huawei-smartlogger
usage: pv
host: host.fqdn
port: 502
- name: battery
type: template
template: huawei-smartlogger
usage: battery
id: 3
host: host.fqdn
port: 502
capacity: 10
```
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