Shelly PRO 3EM Posted August 29 Share Posted August 29 (edited) Hi community, I have an issue with the Pro EM, that it does not show the correct values. My Pro EM is connected to a small solar inverter (800W max) with 2 solar panels. When I look into my OpenDTU at those values and compare them to what the Shelly Pro EM is showing, both values differ much between each other... As you can see from the pictures, Current and Voltage are the same between both, but the "Power Factor" and "Active Power" is different... And if I multiply V*A Shelly get's the same value like the OpenDTU. But why is it showing as different value (active power)? Is there something that needs to be calibrated? FW running on Shelly is 1.4.3 Thanks for the help! Edited August 29 by Shelly PRO 3EM Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
tvbshelly Posted August 29 Share Posted August 29 (edited) Active power takes the power factor (cos phi) into account: Active = U * I * cos phi. The value itself is therefore correct. With a pure PV feed-in, the Shelly should measure a PF of 1. That is really strange. Where exactly is the CT connected and how is the PRO EM connected overall? Edited August 29 by tvbshelly use english Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Shelly PRO 3EM Posted August 30 Author Share Posted August 30 The CT is located directly in the distribution cabinet. what do you exactly mean by "how is the EM connected" Well I can say, that the second CT connector (EM1(0)) is actually working correctly as it shows a power factor of 1. SO as the other one is working, I assume the general connection is good. I read somewhere that there should be some calicration, but I could not find it. Thanks! Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Shelly PRO 3EM Posted August 30 Author Share Posted August 30 I got the problem, there's micro-inverter connected to that phase. And by the looks of it, that inverter is sending the other half powerfactor is "located" on the N line. Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Members thgoebel Posted August 30 Members Share Posted August 30 How many phases do you count in your distribution box? One or three? A picture of the installation would be brilliant… Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
tvbshelly Posted August 30 Share Posted August 30 3 hours ago, Shelly PRO 3EM said: what do you exactly mean by "how is the EM connected" I mean, what thgoebel is already asking for: a picture or an installation drawing would be great. Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
nifoc Posted 17 hours ago Share Posted 17 hours ago (edited) I think I have the same problem in that the EM-50 only reports roughly half of what I would expect the current solar production to be. The first image shows a screenshot of the EM-50, the second and third ones are from the web interfaces of the micro inverters. The micro inverters only produce new measurements roughly every minute, so of course I would never expect the numbers to match 100%, but right now there is a roughly 240W difference (currently no clouds to affect anything that drastically). I have also attached a very, very crude drawing of my installation. I hope that helps. The Relais-Box probably draws a tiny amount of power, but that should be way below <5W. (Active power is negative because I have "Reverse measurement direction" checked in the settings) Edited 17 hours ago by nifoc Added Relais-Bow power draw info Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Members thgoebel Posted 17 hours ago Members Share Posted 17 hours ago (edited) 241W vs. 254,6W ist NOT the half! The difference is within a usual band of tolerance. Moreover, it is unknown whether both screenshots were taken at the same second. Edited 17 hours ago by thgoebel Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
nifoc Posted 16 hours ago Share Posted 16 hours ago 13 minutes ago, thgoebel said: 241W vs. 254,6W ist NOT the half! The difference is within a usual band of tolerance. Moreover, it is unknown whether both screenshots were taken at the same second. I'm sorry, I should've made it more clear that both inverters have their own web interface and only show the "Current power" that they themself currently produce. So since I have two, you have to add them together: 244+241=485 All the screenshots were taken within the same minute. I would expect the EM-50 to show something close to 485, not 254. Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Members thgoebel Posted 16 hours ago Members Share Posted 16 hours ago (edited) Second, not minute, please! Remarkable is the bad power factor of the inverters: 0,67! Did you feed the Shelly pro EM-50 with the same live wire which is used for both inverters? Most likely you’re using a different phase, which would validate the factor of 0,67. Edited 16 hours ago by thgoebel Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
nifoc Posted 15 hours ago Share Posted 15 hours ago 23 minutes ago, thgoebel said: Second, not minute, please! As I have already mentioned in my first reply in this thread, these Deye micro inverters (were the screenshots are from) only produce a new measurement every minute. No matter how hard I try, I will not be able to produce measurements from within the same second. I'm only looking for roughly matching numbers (when comparing the sum of the micro inverters "Current power" to the EM-50 "Active power"). I don't expect them to be exactly the same. 29 minutes ago, thgoebel said: Did you feed the Shelly pro EM-50 with the same live wire which is used for both inverters? Yes (technically it was an actual electrician and not me myself). Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Members thgoebel Posted 15 hours ago Members Share Posted 15 hours ago The power factor of 0,67 should be examined. Sorry for my insistency! Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
nifoc Posted 15 hours ago Share Posted 15 hours ago 2 minutes ago, thgoebel said: The power factor of 0,67 should be examined. Sorry for my insistency! Okay but how? Let's say I let the electrician double check it, what would I ask them to do? (I'm sorry if the answer is obvious to an electrician, but it isn't to me) Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Members thgoebel Posted 14 hours ago Members Share Posted 14 hours ago Perhaps some pictures of your installation would give more clarity? Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
nifoc Posted 11 hours ago Share Posted 11 hours ago I hope the pictures help. I won't be able answer any specific questions, because it was not installed by me (because I don't trust myself around a fuse box). The second (mini) fuse box (that contains the EM-50) was added because it was the cheapest route to go. This is not the main fuse box of the house, but a sub-distributor. Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Dreckfresse Posted 10 hours ago Share Posted 10 hours ago Difficult to recognize 2 Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Members thgoebel Posted 10 hours ago Members Share Posted 10 hours ago (edited) Thanks for the pictures! IMHO, the Shelly pro EM-50 is supplied with L3, whereas the current clamp is installed at L1: May be I’m wrong, cause the course of the brown marked wire behind the terminal block L1 - L3 isn’t visible. But this may be checked with a simple test: Edited 10 hours ago by thgoebel 2 Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
nifoc Posted 10 hours ago Share Posted 10 hours ago Thank you for your help @thgoebel and @Dreckfresse! I will have the electrician double check if the EM-50 really is connected to the same phase or not. He has to come back for some other work (probably) next week anyway. I'll report back once I know more. Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Dreckfresse Posted 10 hours ago Share Posted 10 hours ago @thgoebel It's nice that you see it that way too 👍 Just for completeness and because I've already picked it out Source: https://kb.shelly.cloud/knowledge-base/shelly-pro-em-50 Quote Translate Revert translation? English (American) Finnish French German Italian Portuguese (European) Spanish Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.