Issue with running off Solar with Synapse 5kVA with 2 x US3000 Pylontechs

[CliveS]

Hello,

I'm a total newbie to solar and am still within 2 weeks of having the system installed.  I have picked up an issue with the system which I am concerned about.  The batteries are fully charged by the PV panels by 11am or 12am everyday, and once full charge is reached, the system runs off batteries for the rest of the day.  The installer is unsure what is wrong, and they are trying to find a product specialist at their supplier to assist.  The installer advised me that the system will run off Solar until the load cannot be managed by PV and then batteries will kick in which is not happening.  What does work is to reset the entire system, which then kicks in the PV system and it begins to charge the batteries and supply power to the home.  For example, it's just after 4pm currently, and it has been almost 5 hours since the system stopped charging via PV, and my current SoC of the batteries is 70%, which is not sufficient to last the entire night.

 

Any advice would be appreciated.  I'll have to google your acronyms, but I'll learn.

 

Thank you.

[Coulomb]

1 hour ago, CliveS said:

the system runs off batteries for the rest of the day.

If you mean that the inverter is in battery mode, with solar charging the battery and/or supplying the load, that's what you want, right?

If you mean that there is no PV charging, so the battery supplies all the load and runs down even when full sun is available, then that's certainly a problem.

[Rclegg]

3 hours ago, Coulomb said:

If you mean that the inverter is in battery mode, with solar charging the battery and/or supplying the load, that's what you want, right?

If you mean that there is no PV charging, so the battery supplies all the load and runs down even when full sun is available, then that's certainly a problem.

I believe their issue is once the batteries are charged, they start draining due to carrying the house load. When, what should happen is the inverter should use power from the panels to supply the load, until there is not enough power from then, and only then switch too batteries. 

[jykenmynie]

16 hours ago, CliveS said:

Hello,

I'm a total newbie to solar and am still within 2 weeks of having the system installed.  I have picked up an issue with the system which I am concerned about.  The batteries are fully charged by the PV panels by 11am or 12am everyday, and once full charge is reached, the system runs off batteries for the rest of the day.  The installer is unsure what is wrong, and they are trying to find a product specialist at their supplier to assist.  The installer advised me that the system will run off Solar until the load cannot be managed by PV and then batteries will kick in which is not happening.  What does work is to reset the entire system, which then kicks in the PV system and it begins to charge the batteries and supply power to the home.  For example, it's just after 4pm currently, and it has been almost 5 hours since the system stopped charging via PV, and my current SoC of the batteries is 70%, which is not sufficient to last the entire night.

 

Any advice would be appreciated.  I'll have to google your acronyms, but I'll learn.

 

Thank you.

Can this inverter blend power sources? It might be that the demand for power in your house is too great and the inverter has to use the batteries because the solar isn’t enough?

Have you tried with very low demand in your house?

[CliveS]

12 hours ago, Rclegg said:

If you mean that there is no PV charging, so the battery supplies all the load and runs down even when full sun is available, then that's certainly a problem

Thank you for replying.  I mean the above - there is full sun, and the house is running off batteries.

[CliveS]

1 hour ago, jykenmynie said:

Have you tried with very low demand in your house?

Thanks for the reply.  This is the current situation on my system below.  the system is generating over 1.5kW, and we're using 325 Watts.  The PV goes up even more later on in the day, so I can understand that there are times when we'll need to draw on battery power, however, not to the extent that it's running the entire home off batteries.  

 

i 

[CliveS]

12 hours ago, Rclegg said:

hen, what should happen is the inverter should use power from the panels to supply the load

Yes, that's what should be happening, but it's not doing what it should.  I had a Raspberry Pi fitted as well after the initial inverter and batteries were done, but the problem started prior to the Raspberry being installed.

[CliveS]

I should mention - there are 12 x 320 Watt panels installed as well

[Rclegg]

1 hour ago, CliveS said:

Thanks for the reply.  This is the current situation on my system below.  the system is generating over 1.5kW, and we're using 325 Watts.  The PV goes up even more later on in the day, so I can understand that there are times when we'll need to draw on battery power, however, not to the extent that it's running the entire home off batteries.  

 

i 

 

See post below

Edited September 8, 2020 by Rclegg

[Rclegg]

1 hour ago, CliveS said:

Thanks for the reply.  This is the current situation on my system below.  the system is generating over 1.5kW, and we're using 325 Watts.  The PV goes up even more later on in the day, so I can understand that there are times when we'll need to draw on battery power, however, not to the extent that it's running the entire home off batteries.  

 

i 

 

Wait. I have just looked at this again, properly. 

This is correct. You see Grid Watts is zero? It means the PV is carrying the load AND charging batteries. 

[Rclegg]

As a comparison; here's my ICC as of right now 

House is using 0 watts from the grid. And 3900watts from the PV - load watts is 3400 or so, which means the inverter is supplying that from the PV. When the batteries are being used you will see a minus sign next to the value - eg: -1000 or so. 

 

 

Edited September 8, 2020 by Rclegg

[CliveS]

3 minutes ago, Rclegg said:

As a comparison; here's my ICC as of right now 

House is using 0 watts from the grid. And 3900watts from the PV - load watts is 3400 or so, which means the inverter is supplying that from the PV. When the batteries are being used you will see a minus sign next to the value - eg: -1000 or so. 

 

 

so my problem has come up again - batteries were fully charged at around 11am.  I could hear the inverter fan going on and off and watched the ICC and could see that PV Watts was increasing and decreasing all the time.

 

now, finally, it's done it again.  No PV showing, but it's working off the battery and no charge is going to the battery on the LCD of the inverter.  We can see that the battery is draining as well.

 

 

[Rclegg]

1 hour ago, CliveS said:

I should mention - there are 12 x 320 Watt panels installed as well

 

Okay, so yeah your second screenshot shows an issue. 

How have you configured these panels? That inverter has a max 145VDC - I wonder if the MPPT is not dropping, due to too much voltage from the panels. 12 x 330 is a lot for that inverter, voltage wise. You'd need to have small string sizes, of like 3 to 4 panels, depending on the specs.

[CliveS]

21 minutes ago, Rclegg said:

 

Okay, so yeah your second screenshot shows an issue. 

How have you configured these panels? That inverter has a max 145VDC - I wonder if the MPPT is not dropping, due to too much voltage from the panels. 12 x 330 is a lot for that inverter, voltage wise. You'd need to have small string sizes, of like 3 to 4 panels, depending on the specs.

I called the installer to get the actual numbers, and he says he connected them in groups of 3, so there are 4 groups panels, each with 3 per group. 

 

 

[francois]

Hi @CliveS, 

Is the attached datasheet the one for your inverter?

If so, I see the MPPT operating voltage is between 60V and 115V.

In your one screenshot where the unit is working correctly, you can see the voltage is at 107V (within the limit), but in the other screenshot where it is not working the voltage is 121v (outside the operating limit).

I am not sure if this is your problem, but maybe worth investigating.

Like @Rclegghas said, it's possible that the panels are wired incorrectly and during certain conditions the voltages are exceeding the limits of the MPPT, and then it shuts down.

Synapse 50 48V OffGrid Inverter.pdf

[francois]

1 hour ago, CliveS said:

I called the installer to get the actual numbers, and he says he connected them in groups of 3, so there are 4 groups panels, each with 3 per group. 

 

 

Could you please post the specs of the panels? Might help. 

[CliveS]

Hi Francios.

Thank you for taking the time to check out this issue.

According to my quote, I had 12 x 335 watt panels fitted - and they are fitted in strings of 3.

I checked the side of the inverter, and the max voltage is 145V.  I also checked my little user manual, and i see  a max of 115V for PV Array MPPT Voltage Range.  On the user manual, the Max PV Array Open Circuit Voltage is 145VDC

 

 

Here is the little specification sheet from the user manual:

[Rclegg]

20 minutes ago, CliveS said:

Hi Francios.

Thank you for taking the time to check out this issue.

According to my quote, I had 12 x 335 watt panels fitted - and they are fitted in strings of 3.

I checked the side of the inverter, and the max voltage is 145V.  I also checked my little user manual, and i see  a max of 115V for PV Array MPPT Voltage Range.  On the user manual, the Max PV Array Open Circuit Voltage is 145VDC

 

 

Here is the little specification sheet from the user manual:

The issue appears to be the MPPT voltage range, You're exceeding that and each time you do, the MPPT shuts down.  Ideally, you want 2 panels per string. So you will need to reconfigure them to groups of 2, instead of three. 

 

[francois]

Hi @CliveS, do you perhaps have the specs of your solar panels?

 

[CliveS]

2 minutes ago, francois said:

Hi @CliveS, do you perhaps have the specs of your solar panels?

 

Hi Francios, 12 x 335W panels - that's all I know.

[francois]

4 minutes ago, CliveS said:

Hi Francios, 12 x 335W panels - that's all I know.

Can your installer/supplier perhaps confirm the specs?

[CliveS]

@francoisConfirmed that they are 345 Watt panels that were installed.

[jykenmynie]

5 hours ago, CliveS said:

Hi Francios.

Thank you for taking the time to check out this issue.

According to my quote, I had 12 x 335 watt panels fitted - and they are fitted in strings of 3.

I checked the side of the inverter, and the max voltage is 145V.  I also checked my little user manual, and i see  a max of 115V for PV Array MPPT Voltage Range.  On the user manual, the Max PV Array Open Circuit Voltage is 145VDC

 

 

Here is the little specification sheet from the user manual:

It isn't necessarily obvious to me what they mean here with the MPPT voltage range. Perhaps it is simply the range the MPPT would search for the maximum power. The moment you put some load on your panels, the voltage would drop well into the MPPTs range. That can't be the problem, surely...

[francois]

39 minutes ago, CliveS said:

@francoisConfirmed that they are 345 Watt panels that were installed.

Can you possibly get the rest of the specs like the sample below.

[Coulomb]

On 2020/09/08 at 10:52 PM, Rclegg said:

The issue appears to be the MPPT voltage range, You're exceeding that and each time you do, the MPPT shuts down.  Ideally, you want 2 panels per string. So you will need to reconfigure them to groups of 2, instead of three.

This is becoming a common problem. Panel voltage is so high these days that 3S of 72-cell panels (they are nearly all 72-cell again these days, especially the panels that are over about 315 W) is too much voltage. Yes, 121 V is within the specifications, but it seems to cause problems. Another forumite found that the SCC gets much hotter when running 3S, so it may be shutting down due to over-temperature. The Synapse is basically an Axpert copy or work-alike; they may not have copied the cooling system properly.

Rewiring to 2S6P is a pain, but it will likely fix your problem.