Shelly EM monitoring adjustments

Hardware
1

I have a shelly EM with a single 50A clamp. Its powered by a 120v circuit

I have an EVSE with 2 hots and 1 neutral line. its a 240v dual phase 40A charging station. one of the clamps has the shelly clamp attached 180 out of phase.

The shelly assumes whatever is powering it is also powering the circuit it is clamped to. That’s not the case here. I know I dont need 2 clamps for this as this accuracy would only be ever so slightly improved in this use case. I can do this mathematically. I just don’t know how to explain to HA the math trick I want it to do.

2

It would help if you tell us which EM model exactly. What are you looking for exactly, that isn’t happening? Can the EM have an additional coil?

3

Oh sorry. It’s a shelly EM gen3. it can detect current but because of the voltage being assumed as 120, that throws off any calculation of monthly power consumption. I originally only got it to let me know when the car finishes charging so I didnt care to go another clamp but I should be able to get close enough with just one clamp in this application.

4

Explain better your setup.
US split phase system 120V/120V/N ?
Shelly is measuring only that 240V load or also some 120V load?

5

Shelly is powered by a 120v line. shelly is clamped on one phase of a dual phase 240v line.

6

So clamp it to the same phase that it’s powered from…
Then multiply by 2.

7

so that multiplay by 2 step, how do I explain that to HA?

8

With template sensor.

Another option is to power shelly from L1 and L2 (240V) instead of L1 / N.

9

Does anybody like to share what you got so far with Shelly EM? I got this to calculate how much I expend por month, I used efergy for long time and now I need to change to shelly EM since the efergy end of life.

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10

The Shelly EM series of product are excellent. I like the ones that have the standard ethernet RJ45 plug also. I did have the Shelly EM die unexpectedly at about 13 months. So that is why I like to have wireless, wired and BLE devices for just in case.