littlespark

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I would ask my daughter, but she’s on study leave for exams.

Basically I want a graph that will compare readings from 3 different electric meters.

I want to graph the difference between each reading, not a gradually increasing line.

I’m trying to compare what my hot tub consumes, compared with the house in total, and compared with my PV solar meter.

I read all 3 at 8am and 8pm each day as there will be differences during the day (more sunshine day vs night, more usage etc)

Best software? Word? Excel?
Function of calculating difference each day?
 
It kind of depends on what you have.
Excel or the free 'Calc' of LibreOffice allows you to import text as numeric values and date-time conversions so then you have tables of numbers you can plot. If they are arranged as columns it is pretty easy to get a plot, but a damn sight harder to get a plot looking the way you want it!

When in columns it is easy to create another column of differences. Say you have values in C5 and D5 (row 5, columns C&D) then in E5 you would enter '=C5-D5' as the field and it should give you the difference. Then copy cell E5 and select E6-E100 (or whatever) and past it in. It should automatically increment the 5 to 6,7,8,...etc.

But check one or two manually to be sure as spread sheets and notorious for having odd copy & paste errors...
 
There are other free (e.g. python with matplotlib, gnuplot) and paid options (e.g. MathCAD, MATLAB), but the more powerful they get the more painful the learning curve to go with it.
 
I'm with @DPG on this. Keep it simple and just use Excel.
 
Well, it was a part success, but overall a useless project as all i really needed is the differences between how much each meter reads on any given length of time...

If anyone is interested..

Over 49 days.... (I gave up reading after that)
The hot tub has consumed 77 units. This was at 26 degrees for a week, then up to 36, and it hasn't yet come back down.
The overall electric meter for the house 183 units.... so the tub takes a little less than half the entire consumption.
Solar PV reads 379 generation, but i get paid FIT on 50% of that... so 189~

So looking at this, my PV outweighs the consumption. I might fit a timer to the tub to stop it from heating during the night...

Would it be too much to ask BG to increase how much they pay for my solar generated electricity, as they have increased what i pay for theirs?
 

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littlespark

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If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
United Kingdom
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Practising Electrician (Qualified - Domestic or Commercial etc)

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Help with tables and graphs please
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