IMG_0.MOV

 

Hello, 

I'm a newbie to the solar power generation world, and hoping that someone can help me with an issue. I have 'inherited' a solar set up in a house that I am now using. There are about 4kw of solar panels and at the moment one Pylontech battery US2000c (with three others sitting waiting to be connected. The inverter is a Axpert MkIII 3/5kw and seems to 'see' the battery ok, with 230v being produced as expected. However I cannot get the solar panels to charge the batteries. There is no grid power as this installation is totally off grid. The installation has never charged the batteries from the solar panels, so is this a configuration / setting that I need to change, or something else? 

Edited October 2, 20232 yr by Bob.Upandoon
lost video

 

 

IMG_0.MOV 1.52 MB ·   

 

IMG_0.MOV 1.52 MB · 

 

Hello, 

I'm a newbie to the solar power generation world, and hoping that someone can help me with an issue. I have 'inherited' a solar set up in a house that I am now using. There are about 4kw of solar panels and at the moment one Pylontech battery US2000c (with three others sitting waiting to be connected. The inverter is a Axpert MkIII 3/5kw and seems to 'see' the battery ok, with 230v being produced as expected. However I cannot get the solar panels to charge the batteries. There is no grid power as this installation is totally off grid. The installation has never charged the batteries from the solar panels, so is this a configuration / setting that I need to change, or something else? 

Check if the setting to charge is not to charge from grid only. 

Make sure to set it from PV only if off grid. 

The PV icon flashing indicates that the inverter can see the panels, but is not happy with them. Indeed, you helpfully show that the PV voltage is 124V. This is probably too low to start charging, even though once started, 124V should be enough, down to 120V or 90V or even 60V for some models.

You may be used to the 145V max PV models, for which 124V is quite adequate, heading towards high. I believe that this is an Axpert MKS III, like an MKS II but with the removable display. 

Many thanks for the quick response. The inverter is indeed the model with the removable panel, but this is my first experience of Axpert products, so I'm not familiar with the various models. It was a clear day yesterday, full sun, no clouds, so I don't think that I can improve the level of sunlight. Are you suggesting that the solar panels need to be re-wired?  

 

On 2023/10/03 at 7:30 PM, Bob.Upandoon said:

I'm not familiar with the various models.

Sometimes I wish I was that way too; it would save a lot of posting 🔥⌨️🔥😃.

On 2023/10/03 at 7:30 PM, Bob.Upandoon said:

It was a clear day yesterday, full sun, no clouds, so I don't think that I can improve the level of sunlight. Are you suggesting that the solar panels need to be re-wired? 

Yes, or replace the inverter with a 145 V max PV model (if you can still find them; most seem to be the higher PV voltage models these days).

My wild guess as to what happened: the previous owner had an old low voltage system, and the capacitors dried out (a common problem, well known thanks to the efforts of good people like @BritishRacingGreen). Not knowing this, they replaced the inverter with a new model, and either didn't notice the lack of performance, or the weather was slightly different (warmer weather means lower panel voltage), and they figured what the hell we're selling anyway, no point fixing it now.

The good news is that rewiring the panels for higher voltage is relatively easy, compared to going the other way. You may care to figure out the technical pros and cons; personally I hate the high voltage panels, but I have to admit that this is the way it's all going.

Isn't it wonderful that you are being given this golden opportunity to learn more than you ever wanted to about solar panels and their wiring? 😮

Basically, you will need to arrange your strings of panels such that more are in series and fewer are in parallel. If that's Greek to you, perhaps post a photo of the panels and we can get an idea of what is involved, and how you might re-configure them. You probably have a "PV combining box" as well, we'll need to see that too.

Being totally off-grid, I imagine that this is somewhat of a priority.

Edited October 7, 20232 yr by Coulomb
'they all seem" → "most seem"

On 2023/10/02 at 8:07 PM, Scorp007 said:

Check if the setting to charge is not to charge from grid only. 

Make sure to set it from PV only if off grid. 

Thanks for the advice. I did check this setting and it was not set correctly, however having changed it as suggested, the problem has not changed, so I suspect there is another underlying issue. Hopefully you can advise on my latest post....>>

 

On 2023/10/03 at 3:27 PM, Coulomb said:

Sometimes I wish I was that way too; it would save a lot of posting 🔥⌨️🔥😃.

Yes, or replace the inverter with a 145 V max PV model (if you can still find them; they all seem to be the higher PV voltage models these days).

My wild guess as to what happened: the previous owner had an old low voltage system, and the capacitors dried out (a common problem, well known thanks to the efforts of good people like @BritishRacingGreen). Not knowing this, they replaced the inverter with a new model, and either didn't notice the lack of performance, or the weather was slightly different (warmer weather means lower panel voltage), and they figured what the hell we're selling anyway, no point fixing it now.

The good news is that rewiring the panels for higher voltage is relatively easy, compared to going the other way. You may care to figure out the technical pros and cons; personally I hate the high voltage panels, but I have to admit that this is the way it's all going.

Isn't it wonderful that you are being given this golden opportunity to learn more than you ever wanted to about solar panels and their wiring? 😮

Basically, you will need to arrange your strings of panels such that more are in series and fewer are in parallel. If that's Greek to you, perhaps post a photo of the panels and we can get an idea of what is involved, and how you might re-configure them. You probably have a "PV combining box" as well, we'll need to see that too.

Being totally off-grid, I imagine that this is somewhat of a priority.

Thanks for the input. My understanding is that the whole system is new, no legacy equipment in the set up. However it seems never to have been commissioned correctly. The panels are on a roof and not easily accessible without a mechanical 'cherry picker' going via a neighbour's property, so rewiring them will need planning and access permission. I'd rather exhaust al other 'soft' options before going down this route, so I'm seeking confirmation that the current settings are not responsible for the failure to charge. Incidentally I noticed that the solar voltage yesterday was up at 133V, despite it seeming to be the same cloud free sunny sky, must be some additional pixie dust in the air!

The current settings are indicated with a yellow arrow.

 

 

Seeking confirmation that none of the settings, indicated with a yellow arrow,  in this list are causing the Axpert to not charge the batteries. (see previous post for details)

18 minutes ago, Bob.Upandoon said:

My understanding is that the whole system is new, no legacy equipment in the set up. However it seems never to have been commissioned correctly.

Ah.

18 minutes ago, Bob.Upandoon said:

The panels are on a roof and not easily accessible without a mechanical 'cherry picker' going via a neighbour's property,

Then it seems that the wrong inverter was provided for the system, or at least replacing it will be the easiest way to fix the problem.

You should be able to obtain something like a Kodak OG Plus 5.48 (NOT the high PV voltage model, like the OG-PLUS6.2 or another model whose number I forget). Sorry to be the bearer of bad news.

22 minutes ago, Bob.Upandoon said:

Seeking confirmation that none of the settings, indicated with a yellow arrow,  in this list are causing the Axpert to not charge the batteries.

Confirmed. When all settles down, consider changing setting 27 (float voltage) to a bit lower, like 51.5 V, to have the battery last longer. Setting 26 could go down to 52.5 V.

As a point of interest, are you not using electricity yet, to have the battery not dead flat with no charging at all? Or do you have a generator?

I meant to mention earlier that the various LEDs indicate that the inverter is producing 230 V (flashing AC LED), using the battery as the power source (the solid LED).

On 2023/10/02 at 3:11 PM, Bob.Upandoon said:

 

IMG_0.MOV 1.52 MB · 0 downloads  

 

IMG_0.MOV 1.52 MB · 0 downloads

 

Hello, 

I'm a newbie to the solar power generation world, and hoping that someone can help me with an issue. I have 'inherited' a solar set up in a house that I am now using. There are about 4kw of solar panels and at the moment one Pylontech battery US2000c (with three others sitting waiting to be connected. The inverter is a Axpert MkIII 3/5kw and seems to 'see' the battery ok, with 230v being produced as expected. However I cannot get the solar panels to charge the batteries. There is no grid power as this installation is totally off grid. The installation has never charged the batteries from the solar panels, so is this a configuration / setting that I need to change, or something else? 

Can you  post an image of your inverter's label on the right hand side of it. 

1 hour ago, BritishRacingGreen said:

Can you  post an image of your inverter's label on the right hand side of it. 

Here it is.

9 minutes ago, Bob.Upandoon said:

Here it is.

Thanks, it confirms the absolute minimum pv voltage  is 120V, and if that 124 volts on your display  is your VOC of your panels, its not good. 

For a 120-500V MPPT  you get stable performs from 200v upwards. 

Your SBU setting for output source priority and OSO for charge source priority is good for pv to charge the batter when pv is available. So its got to be that low pv voltage. 

UNLESS there  pv is available  but  suppling the load. Is there any pv power or current displayed on your LCD? 

 

 

 

Edited October 7, 20232 yr by BritishRacingGreen

This is really turning out to be a voyage of discovery. I now know there are 9 panels, 7 of one manufacturer's and two of another. They are not identical spec, close, but not identical. Is it acceptable to have three strings, one of which has the two 'odd ones' and one of the other seven? I think they are set up in three strings of 3, which may account for the 120 > 130 volts that the inverter is seeing. 

4 minutes ago, BritishRacingGreen said:

Thanks, it confirms the absolute minimum pv voltage  is 120V, and if that 124 volts on your display  is your VOC of your panels, its not good. 

For a 120-500V MPPT  you get stable performs from 200v upwards. 

Your SBU setting for output source priority and OSO for charge source priority is good for pv to charge the batter when pv is available. So its got to be that low pv voltage. 

 

 

 

Huge thanks, I've just added some new info on the panel configuration, which I think I will now need to address.

 

1 minute ago, Bob.Upandoon said:

This is really turning out to be a voyage of discovery. I now know there are 9 panels, 7 of one manufacturer's and two of another. They are not identical spec, close, but not identical. Is it acceptable to have three strings, one of which has the two 'odd ones' and one of the other seven? I think they are set up in three strings of 3, which may account for the 120 > 130 volts that the inverter is seeing. 

There are 7 of these panels

7 minutes ago, BritishRacingGreen said:

UNLESS there  pv is available  but  suppling the load. Is there any pv power or current displayed on your LCD? 

I just edited my post, so please take note. 

4 minutes ago, BritishRacingGreen said:

I just edited my post, so please take note. 

👍

21 minutes ago, Bob.Upandoon said:

👍

Can you confirm that at any stage you actually had a pv power reading on the display? It might have gone to the loads and not the battery. 

Edited October 7, 20232 yr by BritishRacingGreen

21 minutes ago, BritishRacingGreen said:

Can you confirm that at any stage you actually had a pv power reading on the display? It might have gone to the loads and not the battery. 

This I base on fact that  setting 01 and 16 matters. You have 01 on SBU meaning that the PV supplies power to the load as top priority. 

You do have setting 16 on OSO which instructs the inverter to charge from solar only. 

But, there is also a relationship  between 01 and 02. If there are limited amount of PV power available then it will serve the load, and only if there is leftover PV then it will also serve the battery. So as far as PV is concerned, if the load and battery competes for pv power, the load wins. 

Edited October 7, 20232 yr by BritishRacingGreen

4 hours ago, Bob.Upandoon said:

Is it acceptable to have three strings, one of which has the two 'odd ones' and one of the other seven? I think they are set up in three strings of 3, which may account for the 120 > 130 volts that the inverter is seeing. 

Those panels are fine to mix, their specs are very close. If the 9 panels are wired up in 3S3P, would it not be the easiest solution to just rewire them at the combiner box and change them from parallel to series? With 9 panels in series that would be around 450Voc.

I think that's the route I will take.

 

2 hours ago, Bob.Upandoon said:

I think that's the route I will take.

 

As indicated the panels are providing too low a voltage. 

Once it works from PV you can lower setting 13 to around 51V or 50V for the battery you have. 54V is too high and might never be reached. 

6 hours ago, jumper said:

Those panels are fine to mix, their specs are very close.

Agreed.

6 hours ago, jumper said:

If the 9 panels are wired up in 3S3P, would it not be the easiest solution to just rewire them at the combiner box and change them from parallel to series?

Ah, yes, no need to get on the roof then. And no need to replace the inverter.

If the PV voltage gets to 450 V, you might have a bit of clipping of PV power, but I suspect that this will be very rare, and it can go to 500 V without damage.

4 hours ago, Coulomb said:

Ah, yes, no need to get on the roof then. And no need to replace the inverter.

I can't take credit for that. I think @Scorp007or someone suggested it on another topic a while back and I was like... 🤦‍♂️ that's such a clever idea 😄

34 minutes ago, jumper said:

I can't take credit for that. I think @Scorp007or someone suggested it on another topic a while back and I was like... 🤦‍♂️ that's such a clever idea 😄

A good reason to not use y connectors but every string to the combiner box. Who knows if a panel goes faulty or just a bypass diode. Having access below the roof one can identify on which string you have a problem. 

Maintenance is a major consideration for me having to do it.