OpenEnergyMonitor Community

Getting started in the USA

I’m wanting to start monitoring my home’s energy usage in preparation for going solar, and the emonPi sounds like it should handle what I’m wanting to do. One thing I’m not 100% clear on from the product/software pages I’ve seen so far: will this show peak power usage? IOW, can I pull a number for the highest energy usage over the past day/week/month/year? If I only wanted monthly totals, I can get those from my past electric bills or online from my utility, but I’d like if possible to size the system to cover the peak load, and that sort of history doesn’t answer that question.

Second question: I’ve been over the “Use in North America” page, and understand (as I’d suspected) that I need two CTs. My home has 200-amp service, and I think that would mean that I couldn’t use the default 100A CTs; I’d rather need to use these:

Is that correct? Are the other changes I’d need to make?

Welcome, Dan, to OEM.

That isn’t, as far as I know, a feature of the software (but I’m not an expert in that area), but the software (emonCMS) will record the power at 10 s intervals, so you should see not only the peak, but the full usage pattern too.

The limiting factor will almost certainly be the size of your service entrance wires - the “standard” c.t. can only accept a cable less than ½" diameter. This is well worth reading:

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Thanks for the informative link–it had me hopeful that I’d be able to use the smaller CTs. So I pulled the cover off my main load center and measured the input wires–0.59" (15mm) diameter. I guess not–back to the larger ones.