Enable/Disable Dynamic Powerlimiter via HTTP

[ele-dev]

I have a simple question. I want to en-/disable the dynamic power limiter via an HTTP request. I read the wiki about the HTTP API but couldn't figure out a working HTTP request that does the job.

Can you tell me if it even can be done via HTTP?
What exact URL is needed and what parameters?

[spcqike]

as the WebUI uses the API, it can be done. however, you need to create a request, that imitates the webui "save" button

e.g.

curl -u "user:password" http://ip/api/powerlimiter/config -d 'data={"enabled":"true","lower_power_limit":"10","inverter_id":"ID 00","inverter_channel_id":"CH 0","target_power_consumption":"-20","target_power_consumption_hysteresis":"10"}'

note, that the parameters are not complete. you must add all parameters, you want to set. the 6 paremeters i wrote are the bare minimum. if one is missing, the response will be "Values are missing!".

all parameters can be found here
https://github.com/helgeerbe/OpenDTU-OnBattery/blob/4ee49a6ecb90a800e57db7554a88b53cb0bf55af/src/WebApi_powerlimiter.cpp#L126C1-L151C1

in a quick test: if you let parameters out, they will be "0". so keep that in mind for your upper Powerlimit, SoC states etc.

edit, just checked and played around. in my case it works with

{"enabled":true,"verbose_logging":false,"solar_passthrough_enabled":true,"solar_passthrough_losses":0,"battery_drain_strategy":0,"is_inverter_behind_powermeter":true,"inverter_id":0,"inverter_channel_id":0,"target_power_consumption":-20,"target_power_consumption_hysteresis":10,"lower_power_limit":10,"upper_power_limit":600,"battery_soc_start_threshold":0,"battery_soc_stop_threshold":0,"voltage_start_threshold":0,"voltage_stop_threshold":0,"voltage_load_correction_factor":0,"inverter_restart_hour":0,"full_solar_passthrough_soc":0,"full_solar_passthrough_start_voltage":0,"full_solar_passthrough_stop_voltage":0}

and

{"enabled":false,"verbose_logging":false,"solar_passthrough_enabled":true,"solar_passthrough_losses":0,"battery_drain_strategy":0,"is_inverter_behind_powermeter":true,"inverter_id":0,"inverter_channel_id":0,"target_power_consumption":-20,"target_power_consumption_hysteresis":10,"lower_power_limit":10,"upper_power_limit":600,"battery_soc_start_threshold":0,"battery_soc_stop_threshold":0,"voltage_start_threshold":0,"voltage_stop_threshold":0,"voltage_load_correction_factor":0,"inverter_restart_hour":0,"full_solar_passthrough_soc":0,"full_solar_passthrough_start_voltage":0,"full_solar_passthrough_stop_voltage":0}

to get your payload easily, you can set it up in webui, query it with

curl -u "user:password" http://ip/api/powerlimiter/config

and just change "true" and "false" accordingly

[stanpete78]

So I could write those values every minute and it would'nt be a bad thing? Ok, good to know.

[schlimmchen]

I'm pretty sure dpl uses the temporary power limit instructions that are lost after a restart of the inverter.

Yes.

[schlimmchen]

So I could write those values every minute and it would'nt be a bad thing?

Well, that's 1440 writes a day. I dont't know anything about the implementation of the flash filesystem on the ESP32, but if its wear leveling is bad, this might lead to write errors "soon". Let's say within a year? Worst case: within 10 days.

It's a little excessive. Try it out and replace the ESP32 if it breaks. It's cheap.

[stanpete78]

I found this: "ESP32s use NOR flash storage, which is usually rated for between 10,000 to 100,000 write cycles (100,000 seems to be the standard these days). Flash can't write single bytes; instead of writes a "page" of bytes, which I believe is 256 bytes. So each 256 byte page is rated for at least 100,000 cycles. When a device is rated for 100,000 cycles it's likely to be usable for at least 10 times that, but the manufacturer is not going to make any promises beyond the 100,000."

[schlimmchen]

So, even with no wear leveling at all (very unlikely), this should be fine for at least 100 days