Wrong Load Usage on Solis S5-EH1P5K-L

[TiagoGomes]

Good afternoon,

I recently acquired a Solis S5-EH1P5K-L inverter, which was installed and configured by a company specialized in this type of service. Overall, I’m satisfied with the equipment’s performance; however, im having a problem with the load usage that I would greatly appreciate your help in clarifying the issue. I’ve already tried getting answers from the installation company, but unfortunately, they were unable to provide a clear explanation.

I’ll try to explain as clearly as possible the issue i'm facing with the inverter: I’m about 99% sure that the household consumption readings during solar production are incorrect. That is, the higher the solar production, the higher the reported household consumption. I even ran a test where I turned off all the circuit breakers in the house and, for example, if the panels were producing around 4 kWh, the inverter indicated a household consumption of about 1.5 to 2 kWh (approximate values, and yes, with all breakers off).

Another example: household consumption with only the essential devices connected is around 0.4 to 0.5 kWh. If I turn on a dishwasher and a washing machine (assuming each uses about 1000 W) and the panels are producing about 5 kWh, the consumption reported jumps to around 4.5 kWh, when it should be approximately 2.5 to 3.0 kWh.

(I know the 0.4 to 0.5 kWh baseline is accurate because I previously had another brand inverter for three and a half years, and that value was consistently observed, just like in the two scenarios I mention below.)

I believe all settings related to the Meter are correct because there are two situations where household consumption is reported accurately:

• In the morning, while the batteries are still charging;
• At night, when there’s no solar production and the batteries are powering the home.

It’s worth mentioning that in the inverter settings, the "Meter Direction" is set to "Reverse". Although I don’t have deep technical knowledge, I’m quite sure this is the correct configuration. During one test, I changed it to "Forward" and the consumption shot up to about 7.5 kWh, which is completely unrealistic.

What it seems like to me (even without much technical understanding) is that when the batteries are at 100% and solar production is active, a significant percentage of energy is being "dissipated" by the inverter (if that’s even possible), instead of being exported to the Grid. And this “dissipated” energy is being counted as household consumption. What I want is for the reported household consumption to reflect only the actual consumption, not the real usage plus some "dissipated" energy.

Could the issue be related to the Grid export settings? or is there a setting that limits the amount of kWh that can be exported to the Grid? If so, is it possible to adjust or disable this limitation?

Here is a Link to a short video I made (recorded on a partly cloudy day, which explains the solar production fluctuations). It clearly shows that whenever there’s a rise in solar production, there’s also a significant increase in the reported household consumption, without any additional devices being turned on:

If you need any further information from me, I’m happy to provide it.

Thank you in advance for your attention!

 

[peufeu]

I recently acquired a Solis S5-EH1P5K-L inverter

I have the 6K.

Please use correct units, power is in kW not kWh.

It’s worth mentioning that in the inverter settings, the "Meter Direction" is set to "Reverse".

My meter is installed in the correct direction and I also have to set it to Reverse for it to work. So... maybe translation error in the menu. This inverter has a few quirks, they all do, this one is not a problem.

What is the value of "Meter placement" setting?

Where is the meter placed?

What's connected the inverter backup port?

What it seems like to me (even without much technical understanding) is that when the batteries are at 100% and solar production is active, a significant percentage of energy is being "dissipated" by the inverter (if that’s even possible)

Not possible. Energy can't simply disappear, it would be dissipated into heat, and with the numbers you give, the amount of heat that would imply is not compatible with the inverter still operating in one piece.

It's probably a display bug or bad calibration.

The inverter does not measure Load consumption. Instead, it measures internally the power it injects on the grid port, then subtracts the meter power. The difference is assumed to be power consumed by the house. However, if one of the measurements is wrong, then the result of the subtraction will also be incorrect.

First thing that comes to mind is: Wrong CT setting on meter or other incorrect meter configuration

CT = Current transformer, usually in the form of a clamp that you put on a wire, measures current in the wire by outputting a proportional current, according to the transformation ratio. For example a 1:100 ratio CT will output 1A for every 100A in the wire.

The meter needs to know the CT ratio of the CT that's plugged into it: if that setting is wrong, measured power will be wrong, multiplied by the ratio error. So if you have a 1:100 CT but the meter is set to 1:50 then it will report half the actual power. Then the subtraction above is wrong. If power is zero, it still reports zero, which means it'll still allow the inverter to do zero export when running on battery at night! That looks suspiciously like your problem.

Please tell what the model of meter is, if it has a CT, then look at the CT. Check there is only 1 wire in the CT clamp. Read the CT label and post it here. If you have no idea what it means, post a pic. Then read the meter manual to check how to make it display the CT ratio, do it in the menu. Check the meter is configured for the same CT ratio that is on the CT label.

You can also shut down the inverter, and compare the meter readings between the meter connected to the inverter, and your official utility meter. With the inverter shut down, both meters should report the same power, which is actual power used by the house.

 

[TiagoGomes]

What is the value of "Meter placement" setting?

Where is the meter placed?

What's connected the inverter backup port?

I will leave a google drive link with photos of the whole instalation including the meter settings on the inverter: https://drive.google.com/drive/folders/1MqreWmvQu_vvbODVLuW7Q0O3Cx_wfk6X?usp=sharing

And there's nothing connected to the inverter backup port.

First thing that comes to mind is: Wrong CT setting on meter or other incorrect meter configuration

Again, I have very little knowledge about the installation itself, but I would also say that the problem has to be related to the meter.

However, is it possible for the issue to be with the meter even when the house consumption appears correct in the two situations I mentioned? That is, in the morning while the batteries are still charging, and at night when there’s no solar production and the house is being powered by the batteries, I’m sure the house consumption is accurate in those cases.

Please tell what the model of meter is, if it has a CT, then look at the CT. Check there is only 1 wire in the CT clamp. Read the CT label and post it here. If you have no idea what it means, post a pic. Then read the meter manual to check how to make it display the CT ratio, do it in the menu. Check the meter is configured for the same CT ratio that is on the CT label.

I'm sorry but where would this CT be installed? Meter model is SDM120CT

You can also shut down the inverter, and compare the meter readings between the meter connected to the inverter, and your official utility meter. With the inverter shut down, both meters should report the same power, which is actual power used by the house.

As long as i know i only have the meter that came with the Solis inverter installed.

 

[TiagoGomes]

The reasons why I believe the "Load" value is incorrect are: as I mentioned, if the batteries are fully charged and the panels are producing, let's say, 4kWh, even if I turn off all the circuit breakers in the house's electrical panel, the "Load" value, both on the inverter and in the Solis Cloud, still shows around 1.5kWh to 2kWh.

The other reason is that before I had this inverter, I was using a Huawei SUN2000-2KTL-L1, and for three years, my average daily consumption was always around 17-20kW, which I think is a reasonable and normal values. Since I installed the Solis inverter (about a month ago), there hasn’t been a single day where the recorded consumption was less than 25kW, and on some days, when there was more sun and the panels were producing close to their maximum, the recorded consumption was 30–32kW.

I can post screenshots of the records on the Solis Cloud App if needed.

 

[peufeu]

However, is it possible for the issue to be with the meter even when the house consumption appears correct in the two situations I mentioned? That is, in the morning while the batteries are still charging, and at night when there’s no solar production and the house is being powered by the batteries, I’m sure the house consumption is accurate in those cases.

Yes

If the CT ratio setting is wrong, the meter will report actual power divided or multiplied by the error in ratio. In other words always wrong except if the value if zero. Because if you multiply zero by anything, it's still zero.

In the two scenarios you mention, the meter should measure close to zero watts, because your inverter is injecting as much power as the house is consuming but not more... so a CT ratio error isn't a problem. But when the inverter is exporting to the grid due to the batteries being full, then your meter will measure this export, this is no longer zero, therefore error.

I'm sorry but where would this CT be installed? Meter model is SDM120CT

Look at the screw terminals on the bottom of your meter and follow the wires. The CT looks like this. I don't see it in your pictures so it's probably in your main electrical panel, since it is supposed to measure power to/from the grid.

 

[peufeu]

there hasn’t been a single day where the recorded consumption was less than 25kW

Recorded on what? The Solis app? In that case it shows the same as the inverter, so the values will also be wrong.

 

[rpdom]

I have the 6K.

Please use correct units, power is in kW not kWh.


My meter is installed in the correct direction and I also have to set it to Reverse for it to work. So... maybe translation error in the menu. This inverter has a few quirks, they all do, this one is not a problem.

I have the 3K inverter. The meter direction on mine is set to normal, not reverse.

 

[peufeu]

The plot thickens

 

[TiagoGomes]

In the two scenarios you mention, the meter should measure close to zero watts, because your inverter is injecting as much power as the house is consuming but not more... so a CT ratio error isn't a problem. But when the inverter is exporting to the grid due to the batteries being full, then your meter will measure this export, this is no longer zero, therefore error.

Ohhhh i understand now, that makes so much sense that in those 2 scenarios the load shows accurate values, because there's no import/export from the grid.

Look at the screw terminals on the bottom of your meter and follow the wires. The CT looks like this. I don't see it in your pictures so it's probably in your main electrical panel, since it is supposed to measure power to/from the grid.

This might be a dumb question but to have access to import/export values from the grid is it mandatory to have the CT? Because I couldn't find it... but also it can be installed in the right side of my main electrical panel which i shouldn't be able too open because it has a security thing from the electrical company (i can cut it but i shouldn't).

Also the company that came to install the Solis inverter reused almost everything from the previous Huawei inverter installation. I saw them replace the meter, but I didn't see them replace/install the CT. Is it possible that they only replaced the meter and left the CT from the old installation?

Just to confirm, both the meter and the CT come in the inverter box, right? And both should be installed because they are "calibrated" to work together?

 

[peufeu]

Just to confirm, both the meter and the CT come in the inverter box, right? And both should be installed because they are "calibrated" to work together?

No you just have to set the CT ratio in the meter menu, no calibration needed.

OK so your story with the Huawei CT makes sense. If it's in a difficult to access spot, the installers maybe didn't bother changing it...

CT ratios are usually like 1:50, 100, 200, 500 etc. So if it's configured for the wrong one, the error is huge.

You can guess which CT you have by shutting down the inverter, and read power (Watts) displayed by both your utility meter and your SDM120.

Currently the SDM120 should display about 2-2.5x the correct value from the utility meter.

Then go into the meter menu (check the manual), check the CT ratio, and adjust it in proportion. For example if the meter displays 2x too high power, and it is configured for CT ratio 1:100, then if you change it to 1:50 in the menu, you'll get correct readings.

Make sure it's not the SDM120CT-MID as the "MID" version is intended for billing purposes and can only have the CT ratio set once to prevent people hacking their electricity bill.

 

[TiagoGomes]

OK so your story with the Huawei CT makes sense. If it's in a difficult to access spot, the installers maybe didn't bother changing it...

Yes, I'm almost 100% certain that they didn't change the CT. Look at this photos: https://drive.google.com/drive/folders/1FrfA6iQppNk3dEPXGadGGGd-4o2A9-F4 , you can clearly see that the CT that comes with Huawei inverter has a white and blue cables which are the same colour's of the cables at the bottom of my Meter. There's a photo with the instructions on how to install the Meter and it says that the CT cables are white and black so they clearly didn't install the one that came with the Solis inverter/meter.

I've already understood that I'll need to open my main electrical panel to access the CT, but I have a question. Do you think it’s better for me to just open the panel and check the ratio on the Huawei CT label and configure the Meter for that ratio, or should I, since I’ve already opened the main panel, ask the company to remove the old CT and install the new CT that came with the Meter, since this way I shouldn’t need to change any settings on the Meter? (I can’t find the CT that came with the Meter/Solis inverter inside the inverter box, so it’s likely that for some reason the company took it... but i can ask them to come again and install it)

Also they reused the RS485 communication cable and in that same photo of the meter installation it says that the RS485 cables are black and red and the ones that i have at the top of my Meter are white and brown... Should I be worried even though in the Solis inverter it says the RS485 is OK?

Make sure it's not the SDM120CT-MID as the "MID" version is intended for billing purposes and can only have the CT ratio set once to prevent people hacking their electricity bill.

My Meter is the SDM120CT. Also in the photos.

 

[peufeu]

Yes, I'm almost 100% certain that they didn't change the CT.

Makes sense

I've already understood that I'll need to open my main electrical panel to access the CT, but I have a question. Do you think it’s better for me to just open the panel and check the ratio on the Huawei CT label and configure the Meter for that ratio, or should I, since I’ve already opened the main panel, ask the company to remove the old CT and install the new CT that came with the Meter, since this way I shouldn’t need to change any settings on the Meter? (I can’t find the CT that came with the Meter/Solis inverter inside the inverter box, so it’s likely that for some reason the company took it... but i can ask them to come again and install it)

Both solutions will give identical results so you can pick the simplest one.

Another option is try various CT settings on the meter until it works. That doesn't require opening the panel.

Also they reused the RS485 communication cable and in that same photo of the meter installation it says that the RS485 cables are black and red and the ones that i have at the top of my Meter are white and brown... Should I be worried even though in the Solis inverter it says the RS485 is OK?

No worries.

 

[TiagoGomes]

Another option is try various CT settings on the meter until it works. That doesn't require opening the panel.

I might just open the electrical panel just to be certain of the correct CT ratio. But according to my calculations, I would say that the recorded export values to the grid should be double. If that's the case and the meter is set to a 1:100 ratio, then I need to change the ratio to 1:50, right?

 

[peufeu]

I'd say the other way around

 

[TiagoGomes]

I'm not gonna lie, but I'm a bit lost right now.

Before changing any settings on the Meter, I noticed it was set to CT 100. I opened the main electrical panel and finally found the CT, and when I looked at the label, it says "In: 100A"... does this mean my CT was properly configured, or am I missing something?

Here’s a photo of the label on the CT I have installed:


I even tried changing it to CT 200, but there wasn't much sunlight, so the export to the grid was minimal, and I couldn't tell if the consumption readings were correct. Tomorrow, I’ll be able to check if it improved or got worse.

Regarding the settings on the Meter, I can only define CT X (where X can be 5, 10, 20, 40, 50, 100, etc.). However, you mentioned that I would need to define the ratio, but I didn’t find any setting to change that, only the CT value…

 

[peufeu]

"In 100A" is the maximum current it can handle.

I found the manufacturer website which says this CT has a 3000:1 ratio so the output current sent to the meter is 1/3000th of the current in the wire.

SDM120 is intended to be used with 100:5 (ie, 20:1) CTs so... unfortunately they may not be compatible... it's a pretty large difference!



You could try to set CT1 to 3000 and CT2 to 1 but it would be better to install the CT that's intended to go with SDM120.

In any case this is installer error so they should fix it and install the correct CT!

 

[TiagoGomes]

You could try to set CT1 to 3000 and CT2 to 1 but it would be better to install the CT that's intended to go with SDM120.

The CT1 only goes up to 600. I also saw the CT2 setting in the meter manual, just like you, but when I scroll through the different meter displays, there's no CT2 showing up. It goes from CT1 straight to the software version.


Yesterday, when I changed the CT1 setting, it also didn’t give me the option to set CT2... However, if I switch back to the original CT, I shouldn’t need to worry about that, since the manual says the default value for CT2 is 5. So, with the original CT installed, I just need to make sure that CT1 is set to 100, correct?

I'm already in contact with the company that did the installation and have asked them to come install the original CT that came with the meter. I’ll let you know as soon as I have any updates.

Thank you very much for your help.

 

[SeaGal]

Hi... further to your PM, there is no more I can add than what @peufeu has said - which is (obviously) all correct and he has gone the extra mile to assist you.

Regarding...

which was installed and configured by a company specialized in this type of service.

all I would say is get the company back to fix it and get it working. Whatever they have done is not correct and you have the data to prove that. Good luck.

Edited to add... your latest post just arrived so good you are getting them to fix it. But they need to be reprimanded if they just re-used an incompatible CT clamp - I thought those things only happened with UK installers

 

[peufeu]

I'm already in contact with the company that did the installation and have asked them to come install the original CT that came with the meter. I’ll let you know as soon as I have any updates.

Good news! After they put the new CT make sure they configure the meter and the it reports correct readings, you never know

 

[TiagoGomes]

Good news! After they put the new CT make sure they configure the meter and the it reports correct readings, you never know

After they install the new CT, what would need to be configured again on the meter? Just verify that the correct CT ratio is set, or is there anything else?

Yesterday, when I changed the CT1 setting, it also didn’t give me the option to set CT2... However, if I switch back to the original CT, I shouldn’t need to worry about that, since the manual says the default value for CT2 is 5. So, with the original CT installed, I just need to make sure that CT1 is set to 100, correct?

By the way, can you just confirm if my thinking is correct here?

Thanks again!

 

[peufeu]

Both correct

 

[TiagoGomes]

Hey again!

Finally got the original CT installed


But of course, as not everything could go smoothly, something had to go wrong. The technician from the company came here this morning, installed the CT, connected it to the Meter, and then left because the batteries were still charging, so it wasn’t possible to run any import/export tests with the grid.

As soon as the batteries reached 100%, I immediately noticed that something was wrong because there was no data recorded for any export to the grid. Shortly after, the technician called me to say that he might have connected the cables to the wrong terminals... He told me he had mistakenly connected them to terminals 5 and 7, but they should have been connected to 6 and 7. I told him that when I got home, I’d try to fix the issue.

When I got home and checked the Meter manual to confirm where the cables should be connected, I saw that it should actually be terminals 1 and 2... I even went back to check photos of the old CT connection and confirmed once again that they are supposed to be connected to 1 and 2. I was speechless.

Anyway, i've already confirmed that the Meter is set to CT1 100. Now I just have one question/concern, there's nothing that can confirm whether CT2 is set to 5, right? I took a photo of the label on the side of the Meter, but I don't think that information is there.


For now, I’m going to assume that CT2 is set to 5 and I’ll keep an eye on the recorded consumption/import/export.

Once again, thank you very much for your help @peufeu !

 

[peufeu]

I think he put in the correct transformer at least!

I thought you had SDM120CT with 5A input, this one has CT2 in the menu, but you actually have the 100mA input version, I don't think there's a CT2 menu option on yours.

 

[TiagoGomes]

I thought you had SDM120CT with 5A input, this one has CT2 in the menu, but you actually have the 100mA input version, I don't think there's a CT2 menu option on yours.

I also thought the model of the Meter was the SDM120CT because that's what it says above the Meter's screen. I had never looked at the side label, but apparently the model is SDM120CTM.

Since there is no CT2 option in my Meter's menu, is it safe to assume that CT2 is set to the default, which according to the Meter's manual is 5?

 

[peufeu]

I just realized it's written on the front panel



...although the inscription is remarkably obfuscated, and the manual is totally unclear about it...

So, this meter expects 100mA input at full scale and this setting doesn't seem to be modifiable, unlike the standard SDM120 which expects 5A at full scale but can be set to various other values via CT2 settings.

Since you got a new 100A to 100mA (1:1000) CT installed, I guess all you have to do is set the CT (or CT1) to 100A in your SDM120 menu.

The previous CT you had was 100A to 33.3mA (1:3000) equivalent to 300A to 100mA, so perhaps it could have worked by setting CT to 300A in the menu to correct in the other direction... if that value was available from the list.