Need a bi-directional energy monitor for my solar panels

Hi all,

I’ve got a small grid-tied 250w solar setup on my garden shed and an ebike with charger inside it on a sonoff switch. I also have a pulse detector on the electricity meter for the whole house that I’ll soon feed into HASSIO. I’m trying to find a way to turn the ebike charger on when I start exporting electricity to the grid (which I don’t get paid for).

The problem is my currently installed energy meter doesn’t monitor the electricity flowing out of the house to the grid, so I’m trying to find a sensor to do that, and rather bizarrely I can’t seem to find one.

Can anyone help? I’ve found stupidly expensive all in one solutions that use a cloud service (big no no for me), but all I want is a current clamp or something that I can feed into a sonoff or similar.

Depends on the type of connectivity you want.

This uses an ESP8266 and standard WiFi.

https://www.amazon.com/Aeotec-Aeon-Labs-ZW095-ZW095/dp/B00XD8WZX6/ref=asc_df_B00XD8WZX6/?tag=hyprod-20&linkCode=df0&hvadid=193989831776&hvpos=1o1&hvnetw=g&hvrand=17540677461906125002&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9029973&hvtargid=pla-315554234105&psc=1
Uses Zwave

I use both. (I had bought the Aeotec before the iotawatt)

$170 is a bit out of my price range, and it also seems wrong to spend that much when a $5 pzem-004 goes into a sonoff and accurately reports current flow, just not its direction.

You mentioned.

I also have a pulse detector on the electricity meter for the whole house that I’ll soon feed into HASSIO

I have a dumb smart meter where i use a pulse counter to let me know what my use and feedin is for the grid by reading the pulses.

I’m very happy for you haha.

Sorry I didn’t word that correctly. You said you have a pulse detector, how does yours work. What is it actually detecting. Do you have a smart meter that pulses to indicate whether you are taking or feeding to the grid?

It gives a pulse regardless of direction, but the actual counter only increments upon import. It’s not directional (hence why I mentioned I was going to set it up and then still asked the question for a solution that could differentiate direction of current flow).

This might work for you.

That appears to be a fairly standard split core transformer with a jack on the end of it’s lead. without circuitry to determine phase lead or lag angle of the AC signal coming out of it, it won’t be able to sense direction of current flow.

Use 2 of them. One on the inverter output and one on the mains.
At the meter, clamp where the inverter feeds to the meter, and another clamp at where the house side connects to the meter.

Just fyi they have the board schematics available on their Github in case you’d like to build your own.

Revisiting this project again, so thought I’d answer.

I don’t think your suggestion will work. The inverter feeds into the house wiring, quite a way from the meter. So if the solar CT clamp says 500w, and the house to meter clamp says 500w. I won’t know if my house is using 1000w or 0w. In this example it’s obvious, which one but with other figures, it won’t be.

It would be 1000w since the clamps on the meter would read a negative wattage (normally) if you were feeding into the grid.

As far as I’m aware, these CT clamps do not give a directional (negative) reading, because they’re measuring AC current, and that spends 50% of its time positive and 50% of its time negative.

To be be clear, the entire purpose of this posts is to find a way to measure AC current AND determine the direction of energy consumption.

Incorrect, CTs are how the power company determines power flow with their net metering.

When you place them on your mains, you place 2 (on a 2 phase system) CTs one with the arrow going “in” the other with the arrow going “out”.