Live current (Amps) vs Wh calculations

[david81]

Now that I finally have my GEM up and running and reporting data to HomeAssistant, I've been doing some digging to check out our usage across our myriad of circuits. One standout has been our septic aeration pump.

I'm reading the BIN32-NET packets via NodeRed and translating that data to MQTT sensors for HomeAssistant. One of the data points I'm pulling out is Current (Amps) to provide "live" power usage for each channel. When using this value, it seems that the GEM is report a bit over 2x what I'd expect to see based on the consumption data (Wh).

The watts value (derived from Voltage*Amps) is consistently reporting ~450W (it runs 24/7), with the exception of a few spikes here and there. When looking at the consumption data, though, it's showing just over 200Wh for any single hour of the day. Not knowing anything about the motor running the aerator, I'm not quite sure which one to believe at this point. All the other channels seem to be in line with what I'd expect, so I'm assuming it's due to the type of load involved here?

[ben]

Now that I finally have my GEM up and running and reporting data to HomeAssistant, I've been doing some digging to check out our usage across our myriad of circuits. One standout has been our septic aeration pump.

I'm reading the BIN32-NET packets via NodeRed and translating that data to MQTT sensors for HomeAssistant. One of the data points I'm pulling out is Current (Amps) to provide "live" power usage for each channel. When using this value, it seems that the GEM is report a bit over 2x what I'd expect to see based on the consumption data (Wh).

The watts value (derived from Voltage*Amps) is consistently reporting ~450W (it runs 24/7), with the exception of a few spikes here and there. When looking at the consumption data, though, it's showing just over 200Wh for any single hour of the day. Not knowing anything about the motor running the aerator, I'm not quite sure which one to believe at this point. All the other channels seem to be in line with what I'd expect, so I'm assuming it's due to the type of load involved here?

Likely just bad power factor on the pump. From what I've seen a lot of them consume in the 80W range.

[david81]

So...which number can I trust to be accurate? The live amps or the amps calculated by working backwards from the Ah over time? Neither?

I'm working on getting some details on what exactly is installed (a new one was put in this year, so I'm hoping it's close to whatever the rating on the motor is).

[ben]

So...which number can I trust to be accurate? The live amps or the amps calculated by working backwards from the Ah over time? Neither?

I'm working on getting some details on what exactly is installed (a new one was put in this year, so I'm hoping it's close to whatever the rating on the motor is).

Using VA to estimate Watts only works for purely resistive loads. Watts give you the true power usage.

Give this a read here: https://www.brultech.com/files/Differen ... d%20VA.pdf