Reading data from a Solax solar power installation via cloud API

While there is an integration for Solax devices, it only works with the newer devices with a reverse proxy.
As a (hopefully) temporary solution, I read the data from the SolaX cloud service. The service returns a JSON which is too long to be stored as a sensor state (longer than 255…). To read different values from the JSON, my solution is to query the API multiple times, reading a different value from the JSON each time.

- platform: rest
  method: GET
  scan_interval: 60
  value_template: "{{ value_json['result']['acpower'] | float }}"
  unit_of_measurement: W
  name: balkonkraftwerk_acpower
- platform: rest
  method: GET
  scan_interval: 300
  value_template: "{{ value_json['result']['yieldtoday'] | float }}"
  unit_of_measurement: kWh
  name: balkonkraftwerk_yieldtoday
- platform: rest
  method: GET
  scan_interval: 3600
  value_template: "{{ value_json['result']['yieldtotal'] | float }}"
  unit_of_measurement: kWh
  name: balkonkraftwerk_yieldtotal

According to their documentation, you are not allowed to query the API too often, but in my experience so far, the API updates only every 5 minutes or so anyway.
The API provides additional values:

item / Description / Accuracy / Unit
inverterSN Unique identifier of inverter (Serial No. of inverter) - - 
sn Unique identifier of communication module (Registration No.) - - 
acpower 1 W 
yieldtoday 0.1 KWh
yieldtotal 0.1 KWh
feedinpower Grid.power.total1 W 
feedinenergy 0.01 KWh
consumeenergy 0.01 KWh
feedinpowerM2 1 W 
soc 1 % 
peps1 Inverter.AC.EPS.power.R 1 W 
peps2 Inverter.AC.EPS.power.S 1 W 
peps3 Inverter.AC.EPS.power.T 1 W 
inverterType Inverter type, details refer to Table 4 in appendix - - 
inverterStatus Inverter status, details refer to Table 5 in appendix - - 
uploadTime Update time(2016-10-26 17:33:01) - 
batPower 1 W
powerdc1 Inverter.DC.PV.power.MPPT1 1 W
powerdc2 Inverter.DC.PV.power.MPPT2 1 W