Power consumption data capture over time for households (to size solar)

[Dino]

Hello - thank you for your help -

   This is probably a very boring, very basic project:

   I need to capture the amperage on the two power lines coming into the circuit breaker box in a house over time, as well as the amperage on a few of the circuits in the breaker box.  This is in order to properly size solar systems.

  A few details:

   - split phase, 240 volt power, 200-amp service (100 amps max/line) (North American, U.S.)

   - minimum 1 second intervals, can be much higher (up to 15 seconds would be acceptable if need to limit file size)

   - The ability to capture inrush current is not necessary but is a big plus

   - 8 channels desired

   - 2 channels minimum

   - Plan to use clamp meter probes to go around the hot wires (Didn't find any here, so I am thinking of using these: https://www.amazon.com/gp/product/B07Z7TXY8J and any adapters necessary) 

   - Data capture will be to a dedicated laptop (Windows, possibly Macbook) with lots of free disk space

   - File size of 10 Gig or more is not a problem

   - Ethernet (preferred) or USB connectivity

   - Would like to capture a few days worth of data - maybe 7 days max

   - Would like to view & manipulate the data in appropriate software (DAQami?) or import it into Excel for graphing, extracting/calculating total amp-hours, etc.

   - It has been a few years, but I have worked in several computing languages for many years, including visual languages, and I have also worked for a short time with Raspberry Pi - so I am not new to computing, nor to electrical panels, both residential and industrial.

   I know your company is all about data acquisition - can you recommend the products to accomplish this project?  (I've poked around your site a bit, so I have an idea, but I don't really want to waste money by ordering anything that isn't going to in the end work for this project;  thanks for understanding.)

   Thank you very much for your assistance…

[DAQman]

The clamp you have referenced can be set to either 1mV/A or 10mV/A and the output is a 60Hz waveform. The datasheet doesn't say, but I suspect the output signal has higher than typical output impedance, making it more challenging to use more than one. You need a simultaneous 24-bit device with a low input range and can sample fast enough to capture 60 Hz. 24-bit devices use delta-sigma converters that oversample to achieve high accuracy. A side effect of oversampling is that it acts like a low-pass filter to remove unwanted noise. The DT9824 meets these requirements. It comes with the QuickDAQ software; however, consider the DASYLab software because it would provide better control over how data is logged to the file.

[Dino]

Thank you for your response.  Actually, I don't need fast capture - somewhere in the range of 1x per second to 4x per minute.  Based on that, do you still recommend the DT9800 series?

[DAQman]

If the current clamp output is a maximum of 400mV at 60 Hz, capturing data once per second will produce garbage. You'll need to capture at least 120-240 samples per second and calculate and save the RMS value. The DASYLab software can do this.  More importantly,  the device I recommended is accurate down to millivolts. Maybe a different sensor is needed. Here is one with a 0-5 VDC RMS output. If you use something like this, we have several low-cost devices that could be used. 

https://bravocontrols.com/shop/current-sensor-single-phase/