Wired energy monitor

Hi there,
i need to monitor the energy usage of a 200A single phase guest house in Ghana.

I have no requirement for the thing to be wireless, happy for it to sit next to the incomer and be hard wired to the CT clamp.

can someone advise of a solution.

no wifi or ethernet network will be available- and i want the cheapest solution possible


So if you have no internet (cos no wifi and no ethernet) then remote monitoring isn’t important.
so what about
it is just a electricity meter…
200Amps for a house is QUITE a lot?

I think your cheapest would be a home-made analogue conditioning circuit and an Arduino, feeding serial data to a Raspberry Pi running emonCMS.

See the ‘Learn’ section for more details of what you need for the Arduino.

@david From what I can read on the label, that requires a direct connection (not a current transformer) and it’s only 100 A.

The OP says “Guest House” so I’d guess there’s a big water heating and cooking load at peak times.

Yup its only 100A, i couldn’t find a single phase to handle 200A.
From what I’ve found UK rules at least, a single phase is max 100A.

I hadn’t thought of the guest house as being for many guests - D’oh.

If its for heating hot water perhaps the OP may want to consider Solar Thermal?

Just to say that the standard OEM solution of an emonTx and emonBase is wireless but does not use wi-fi and has no need for ethernet, except you will need some display device? If you only need two CTs then an emonpi might be sufficient?

But what monitoring do you want to do? That’s going to affect the requirements. Just instantaneous display? Or logging as well? How many things (currents, voltages, powers)? Display as numbers or graphs, alarms?

HI Dave, thanks for your response,

I need data logging ideally only kWh electricity i dont care about anything else- it would be great to have HH data for 6 months, but just a total consumption to date would suffice ie a kWh meter.

when reading the information for Emonpi it seemed to be saying communication was over the local wifi or ethernet cable- i must have got that wrong.

FYI it’s a small guest house in Ghana- has 10 double rooms, all of which has fans and lights. its main loads are 5 large chest fridges/freezers in the kitchen and Bar, and the computer lab in the community learning centre- 200A might be overkill but my guess is it will definitely go above 100A at some point

Normally, the emonPi expects to be on a local area network, and behaves as a server to interact with the user via a web page. I’m not a RPi expert, but I understand you can connect a keyboard, screen and mouse to use it as a normal computer.

It would be much more versatile and probably convenient solution if you could set up a local wired or WiFi network, then you could have the RPi next to the incomer and access the data on your office computer.

Then an emonpi by itself would be sufficient I think, since it includes a small display. But any regular electricity meter would also serve?

And to answer Robert, yes you can attach an HDMI display and a USB keyboard and/or mouse to a raspi.

But as it comes, that display is very limited.

And is emonCMS then usable in much the same way as on any other (networked) machine - I’m guessing it’s at IP ?

Well I don’t have one so I don’t know but Changing emonPi LCD display options? suggests it is possible to change what is displayed.

Yes, there’s a discussion at Direct connection EmonPi to local HDMI display

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