# OpenEVSE out of balance with solar **URL:** \ **Category:** OpenEVSE\ **Created:** [1 October 2026 15:24 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384 "2026-10-01T15:24:03Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [4 October 2026 14:51 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/21 "2026-10-04T14:51:36Z")
Arrgh! My problem is the diagram, I drew it about 10 years ago but failed to include any of the CT numbers. When I recently decided to publish it here to help solve my export problem, I numbered the CT’s but mixed up Emon pi CT1 and CT2. eMC CT1 and CT2 were and remain correctly labelled. I have now changed the diagram to reflect how it is wired. I must emphasise I have not changed the position of any CT’s just changed the numbers on the diagram for the Emon pi. The original export problem remains as before. New diagram attached ![car_21](https://community.openenergymonitor.org/uploads/default/original/3X/2/b/2b9dda148d422f7286623e57e2a0a6a9fa9f28d0.jpeg) ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [4 October 2026 14:52 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/22 "2026-10-04T14:52:47Z")
Well spotted @Robert.Wall ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [4 October 2026 16:18 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/23 "2026-10-04T16:18:23Z")
Looking at your corrected 4/10/26 diagram, emonPi CT1 is reading the **TOTAL** infeed¹, emonPi CT2 is reading the PV Infeed. You must not use power1pluspower2 (as we do) for total power input². What I think you need for your EV diverter is power1 **minus** power2, i.e. the power between the grid meter and Henley block 1 – which is essentially the same as eMC CT1. Note 1. except at night, when it will miss the “stay alive” consumed power to all the inverters, which CT2 will catch. Note 2. If you have a timing problem between emonPi power1 & power2, you could turn CT2 around and use -1.0 in “scales = …” in emonhub.conf. Then power1pluspower2 will actually be power 1 - power2 and the minus in “scales” corrects the sign for emonCMS. This bypasses the time delay because the arithmetic is done on readings from the same sample interval, which is not guaranteed when you do it in emonCMS. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [4 October 2026 17:51 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/24 "2026-10-04T17:51:32Z")
Yes indeed. I believe all in your last post para 1 is correct. Checking how the openevse: grid\_ie process list setup is currently (and has always been) you will see that it uses emonpi:power2-power1 but the result is -12W and never changes. There is not a drop-down option to use power1-power2. How do I change to power1-power2? Your note 1 is correct but does not trouble me. Note 2 is noted and hopefully I can return to it later if necessary ![12kW_05](https://community.openenergymonitor.org/uploads/default/original/3X/6/f/6f7f6a235b59ca20e7b7c9e7969ae73ddce0cae1.jpeg) ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [4 October 2026 17:57 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/25 "2026-10-04T17:57:26Z")
> [@BrianD](#): > > How do I change to power1-power2? I told you above in Note 2. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [4 October 2026 19:31 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/26 "2026-10-04T19:31:57Z")
> [@Robert.Wall](#): > > I told you above in Note 2. OK, so I can’t do it in the process list setup. ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [4 October 2026 22:34 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/27 "2026-10-04T22:34:49Z")
Of course you can, but you risk power1 and power2 coming from different sampling intervals with a 10 s difference between them - I just thought reversing the c.t. so that power2 becomes -power2 so that power1pluspower2 is actually power1plus(minuspower2) was the best way of going about it and guaranteeing that the two numbers were consistent. If you really need to do it in the process list, do it for power2 (the last to be done), and after you’ve done all the things for power2 on its own: Reset to Original _{gives power2}_ × `-1` + feed `power1` _{gives power1 + (-power2) = power1 - power2}_ log to feed `power1minuspower2`_{or whatever}_ > [@BrianD](#): > > Checking how the openevse: grid\_ie process list setup is currently (and has always been) you will see that it uses emonpi:power2-power1 but the result is -12W and never changes. Where can I see that? Remember all I know about your setup is what is in this Topic. A process list is executed when its data arrives in emonCMS. In which Input’s process list is power2 - power1 calculated? You are not doing it in post no.24, that is logging the Input `grid_ie` to a Feed you are calling power2-power1, it is not doing the maths. Where does the Input `grid_ie` get its data from? Is it getting data regularly? It looks like it isn’t, it is 3 days old. If you put the maths in power2, it will be calculated every time the emonPi sends its readings to emonCMS, and with the value in a Feed, it is readily available at any time and less than 10 s old. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [5 October 2026 17:37 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/28 "2026-10-05T17:37:21Z")
Well, that was quite a day! It all went downhill for some reason and after hours of faffing about I did what my wife suggested ‘turn it all off and on again’. Now it’s all stable again I have decided to stop burning more of your time especially on such an old product that you no longer sell. I have reverted to using the settings that have served me so well for the last 7 years. The effort to understand why it needs to use a feed from the water heating energy diverter will remain a mystery for now as the effort is not justified by the result. However, in answer to your question there is an image showing the derivation of power1 and power2 for the emonpi in my original post but I have included it here again. ![12kW_04](https://community.openenergymonitor.org/uploads/default/original/3X/7/a/7a052480b01e92efc66987c023cc60d02e82b598.jpeg) ---
**Author:** ![glyn.hudson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/glyn.hudson/32/35003_2.png) [@glyn.hudson](https://community.openenergymonitor.org/u/glyn.hudson)\ **Post date:** [5 October 2026 17:46 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/29 "2026-10-05T17:46:21Z")
Can you show us the Input processing list for Power1? Why is there an Input being subtracted from Power1 before logging to feed, and whats being published to MQTT? ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [5 October 2026 18:09 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/30 "2026-10-05T18:09:31Z")
> [@BrianD](#): > > an image showing the derivation of power1 and power2 for the emonpi in my original post but I have included it here again. But it doesn’t show that at all! It only shows the input values and that there is processing, not what the actual steps are, and the names of the Feeds involved. I was going to suggest you try [Rubber duck debugging - Wikipedia](https://en.wikipedia.org/wiki/Rubber_duck_debugging), but as you’re not pursuing the problem, it’s academic. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [5 October 2026 19:43 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/31 "2026-10-05T19:43:18Z")
Ha that is brilliant. I had no idea others use this technique and that it has a name, that is excellent! I have attached what I believe @glyn.hudson is asking for but I must point out that I did not write this stuff it was kindly provided for me by a member of the old forum. I don’t know what is being published to MQTT because I don’t know how to find out. Maybe I shall go and read up on it and learn. ![power1](https://community.openenergymonitor.org/uploads/default/original/3X/c/b/cbbe2d2f0e1ff21b167e2a416d47d3c8d390cbc1.jpeg) ---
**Author:** ![glyn.hudson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/glyn.hudson/32/35003_2.png) [@glyn.hudson](https://community.openenergymonitor.org/u/glyn.hudson)\ **Post date:** [6 October 2026 15:01 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/32 "2026-10-06T15:01:55Z")
Ok, that looks fine. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [6 October 2026 17:28 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/33 "2026-10-06T17:28:53Z")
It’s very kind of you to continue investigating my ‘problem’ I am embarrassed to burn up your time in this way but if you choose to continue, I am of course very grateful. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [8 October 2026 09:33 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/34 "2026-10-08T09:33:27Z")
While discussing the problem with my rubber duck it occurred to me that maybe other people simply don’t use the Export mode. Perhaps it simply does not work using a feed from the emonpi? Are any of the many people following this thread successfully using export mode with a feed from the emonpi? ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [8 October 2026 10:39 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/35 "2026-10-08T10:39:26Z")
Try reading the OpenEVSE manual to your rubber duck, and then explain to him either that the assumptions it makes and the information it needs in Export mode is the same as Production - in which case you’re going to have to explain to him the assumptions you’ve made and how they’re different to those OpenEVSE made; or if it’s different, explain to him how you’re going switch to sending different data in each mode, and how you make that data fit OpenEVSe’s expectations. ---
**Author:** ![BrianD](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/briand/32/5022_2.png) [@BrianD](https://community.openenergymonitor.org/u/BrianD)\ **Post date:** [8 October 2026 15:39 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/36 "2026-10-08T15:39:33Z")
My rubber duck Matilda is a hen, but she is not offended. This is what puzzles me too. I am indeed using emon/emonpi/power2 for Production and emon/SolarDiverter/Grid for Export. Given that I don’t understand why this is necessary I find it impossible to explain in simple terms to Matilda. Her response was if it’s doing what you want then why mess about with it? You will only break it again. ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [8 October 2026 16:32 UTC](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384/37 "2026-10-08T16:32:45Z")
> [@BrianD](#): > > Given that I don’t understand why this is necessary If the designers didn’t think it was either necessary or useful, they wouldn’t have included the option. So why have they? What is it doing or trying to do (differently) in each mode? It may well be that you don’t need to change modes, or you might find one is more suited to your application than the other, or you might find the processing you’re doing in the emonPi is negating the need for the other mode. If you do decide you want or need to switch, then your starting point is, what does it want to know in each mode? That’s what you need to find out. When I was earning my living doing applications and project engineering, these are the common questions I had to find answers to. [Previous page](https://community.openenergymonitor.org/t/openevse-out-of-balance-with-solar/30384.md?page=1)