# How many current sensors to provide production and consumption?

I’m hoping to get an EmonPi to monitor my production and consumption, down the line I’m hoping to divert my excess energy to a water tank.
For now, all I want to do is measure my production from solar and consumption from the grid.
I have a sensor already which works in a similar way, but will only provide either just production from solar, or a non-directional flow of either production or consumption based on how much power I’m generating.
I assume this is because the current sensor I have is non-directional, and also assume the current sensor of the EmonPi is the same.
Based on those two assumptions, I don’t see how one sensor will provide both production and consumption, so (again) assume I’ll need two.
Please clear up my wild assumptions.

Wrong - if you also have an a.c. adapter, which allows you to determine the relative phase of current and voltage. See the ‘Learn’ section for the theory and an explanation.

So if you have a single phase mains (and I think you probably do have - much like our domestic supply in the UK) then the two c.t. inputs on the emonPi will fulfil your present needs.

Thanks for that!
I’m in Australia, so Emon don’t provide an A.C. adapter.
So… do I need to utilise both the C.T. inputs or will one suffice assuming I can get my hands on an A.C. adapter, (or convert a UK one)?

I’ve not tested it nor measured its parameters, but fellow countrymen of yours say it’s OK.

Thanks again, so all I need is an A.C. adapter, and a single C.T. input, or two?

One c.t. on the grid connection will give you what your supplier’s meter knows (but might not show): nett power transfer between your house and the grid. If you add a second, that will show you PV generation, and from the two you know your consumption.

Superb, thanks very much!

Obviously that should have been “If you add a second on the PV infeed, that will show your PV generation…”