Are Power and Yield values match the inverter output or we must account for some loss ? #476
Replies: 5 comments 7 replies
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What shelly device are you using? the only shelly product for "measuring" ist the EM series. i have an EM3 installed wich i use to set the power limit with the openDTU and an EM directly at the HM-800 for measruring solar power. |
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Thanks for your reply! But based on your answer, I should understand that the power reported by OpenDTU is the real power sent on the AC wire ? |
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Difference is 5-7% for me... That's a lot.... I have the possibility to use either Shelly Plug, Plug S or Plus 1PM. I don't know which one of them is most accurate though. I will ask or test. Peak production is 1600W. |
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For ref: https://www.facebook.com/groups/ShellyIoTCommunitySupport/permalink/5547181905381128/ |
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To close the conversation, here is how I solved it. Turns out the actual equation is:
This link - provided by @Solarteur - helped me (#394 (comment)) In Home Assistant, I have creating sensors for each inverter, computing the real power:
Than, I have created a sensor accounting for my plug error rate:
I have created also an entry which is the sum of all 4 Thanks to that, I have the exact same power number both reported from shelly plug and DTU: The same rule holds true for the energy accumulated (YieldDay for DTU and energy grabbed from shelly plug) |
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Hello,
I have installed OpenDTU, this is awesome. But I see that the power / yield values do not match what my Shelly device reports for energy and power. The Shelly device report a little less. But I know that the Shelly devices have also some margins of error.
If I want to get the most accurate values in Home Assistant, I am wondering if I should take the values from the Shelly device or from the DTU. I don't know how accurate the values from the DTU are ?
Example: regarding the power value from the DTU: is it a theoretical power value converted from the AC input, not accounting for any loss, or it is really the real power injected in the wires from the inverters ?
Thanks!
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