# PoCo Voltage Calibration

Hello,

I’ve been happily moving along with my two IotaWatts but since these things give a level of customization that’s above and beyond I wanted to dial in the accuracy.

When I first installed my IotaWatts I calibrated the voltage from 10.79 down to 10.75.

My last billing period showed that I was a net consumer of 374 kWh

During the same time the IotaWatt that measures the mains calculated 385 kWh

Which right off the batt is stunning accuracy!! Amazing job @overeasy!!

I want to get even closer because why the heck not! Does this math check out for further calibration?

[Old Calibration Factor] - (1 - ([PoCo Power Usage] / [Measured Power Usage]))

10.75−(1−(375÷385))

New Calibration Factor: 10.724025974

Either way I’m not sweating it because it’s already quite accurate for my use case.

Actually, scratch all of the above. I pulled my 15m data from my power company and added up the daily amount and compared it to my IotaWatt…there was a drum roll

0.004764912556%

Difference between the two, with the IotaWatt actually reading just a hair low on most days.

In that data I did find that the PoCo fubared one day of data collection which likely explains the difference:

Data for period starting: 2020-03-10 00:00:00 for 24 hours
Energy consumption time period Usage(Real energy in kilowatt-hours) Reading quality
2020-03-10 00:00:00 to 2020-03-10 00:15:00 0.33
2020-03-10 00:15:00 to 2020-03-10 00:30:00 0.3
2020-03-10 00:30:00 to 2020-03-10 00:45:00 0.26
2020-03-10 00:45:00 to 2020-03-10 01:00:00 0.29
1.18

They only captured 1.18 kWh on 3/10/20 and likely “guessed” at the rest of the data.

IotaWatt measured 12802.95 Wh (12.80295 kWh) on that day

Glad I checked the numbers on a per day basis, it’s waaaay closer than I expected.

Now, my current calibration of 10.75 * 0.004764912556 = 0.05214450305

10.75 + 0.05214450305 = 10.8021445

Which is basically the original 10.79 calibration.

I’m going to move back to the original 10.79 and see where that gets me.

A further testament to your great work @overeasy