My son had 2 x Deye 5kW inverters installed in parallel with 2 x Deye 5.32 kWh batteries. The slave has 8 x 425W panels (3400 W) on one string and the master has 4 x 425W panels (1700W). We will be adding busy to get this 1700W changed as the voltage is a bit low. We will be adding 2 more 425W panels as this is what the roof space allows.

This was installed in a new built house and the grid was not conencted yet. My son moved in a few days ago and could track the production. Yesterday the grid was connected. The moment the grid came on, the total PV went down by about 500W. This morning I noticed that the PV power curve is starting later than yesterday. I montired it and then asked my son to switch off the incoming grid mains switch. Immediately the production increased by about 500W.

Is this normal? If not, why is this happening and what needs to be changend?

9 hours ago, Giel said:

My son had 2 x Deye 5kW inverters installed in parallel with 2 x Deye 5.32 kWh batteries. The slave has 8 x 425W panels (3400 W) on one string and the master has 4 x 425W panels (1700W). We will be adding busy to get this 1700W changed as the voltage is a bit low. We will be adding 2 more 425W panels as this is what the roof space allows.

This was installed in a new built house and the grid was not conencted yet. My son moved in a few days ago and could track the production. Yesterday the grid was connected. The moment the grid came on, the total PV went down by about 500W. This morning I noticed that the PV power curve is starting later than yesterday. I montired it and then asked my son to switch off the incoming grid mains switch. Immediately the production increased by about 500W.

Is this normal? If not, why is this happening and what needs to be changend?

Did you perhaps had a time setting on the timers and ticked to use grid charge? 

What SOC was the batteries at when the grid was switched on? 

Also check your Setting for "Grid Trickle Feed". Normally set between 20 -  50W, but maybe set to 500W by mistake.

25 minutes ago, TimCam said:

Also check your Setting for "Grid Trickle Feed". Normally set between 20 -  50W, but maybe set to 500W by mistake.

 Hi Tim.

Here are the current time settings

Giel

40 minutes ago, Scorp007 said:

Did you perhaps had a time setting on the timers and ticked to use grid charge? 

What SOC was the batteries at when the grid was switched on? 

Hi Scorp007

We are using grid time settings as shared with Tim. I cannot remember wat the SOC was when the grid came on.

Giel

Just now, Giel said:

Hi Scorp007

We are using grid time settings as shared with Tim. I cannot remember wat the SOC was when the grid came on.

Giel

Untick the charge from grid during good sunshine and do the test again. 

19 hours ago, Giel said:

My son had 2 x Deye 5kW inverters installed in parallel with 2 x Deye 5.32 kWh batteries. The slave has 8 x 425W panels (3400 W) on one string and the master has 4 x 425W panels (1700W). We will be adding busy to get this 1700W changed as the voltage is a bit low. We will be adding 2 more 425W panels as this is what the roof space allows.

This was installed in a new built house and the grid was not conencted yet. My son moved in a few days ago and could track the production. Yesterday the grid was connected. The moment the grid came on, the total PV went down by about 500W. This morning I noticed that the PV power curve is starting later than yesterday. I montired it and then asked my son to switch off the incoming grid mains switch. Immediately the production increased by about 500W.

Is this normal? If not, why is this happening and what needs to be changend?

From which inverter mppt is the pv drop coming from? Also is see on the master pv string is very close to the startup voltage of the mppt without having your specific panel specs the master4string 425w) is just about 10v above the mppt startup. Add the extra 2 panels to the 4S1P string to make it 6S1P.

1 hour ago, TaliaB said:

From which inverter mppt is the pv drop coming from? Also is see on the master pv string is very close to the startup voltage of the mppt without having your specific panel specs the master4string 425w) is just about 10v above the mppt startup. Add the extra 2 panels to the 4S1P string to make it 6S1P.

Hi Talia

I am not sure from which inverter MPPT the drop is coming from. I could have checked it, but cannot remember.

You are 100% correct about the 4 panels being close to the inverter startup voltage of 150V. We are busy addressing this and this should be sorted soon. These 4 panels are east facing and we can add two as that is the space available on that roof.

We will also add 8 more panels on the west facing roof on MPPT2 of the master. This will then be the maximum solar capacity the roof space can handle. The total solar will then be as follows:

Master MPPT 1: now 4 panels x 425W (1700W) to increase to 6 panels x 425W (2550W)

Master MPPT 2: now 0W to increase with 8 panels x 425W (3400W)

Slave MPPT 1: now 8 panels x 425W (3400W) and will stay like so.

Total now 12 panels x 425W (5100W) to increase to 22 panels x 425W (9350W). This is potentially an overkill, but only the slave 8 panels are north facing. The master MPPT 1 panels are east facing and the master MPPT 2 panels will be west facing. So the capacity is kind of the slave MPPT 1 panels (3400W) plus either the master MPPT 1 panels or the master MPPT 2 panels or something inbetween.

Giel

6 hours ago, TaliaB said:

From which inverter mppt is the pv drop coming from? Also is see on the master pv string is very close to the startup voltage of the mppt without having your specific panel specs the master4string 425w) is just about 10v above the mppt startup. Add the extra 2 panels to the 4S1P string to make it 6S1P.

The one thing why it is perhaps not the 4 panels if the MPPT did produce(150V) is that after starting the PV can drop down to 125V before it would stop producing. As per specs but one can add a bit of margin like 5V and expect to keep on working as long as the voltage stays above 130V which it should if a clear sunny day during peak hours. 

I am in Pretoria  and my son in Somerset West. I hope the additional panels will be installed within a week or so. Then we will see if the response regarding the 500W is the same or not.

6 minutes ago, Giel said:

I am in Pretoria  and my son in Somerset West. I hope the additional panels will be installed within a week or so. Then we will see if the response regarding the 500W is the same or not.

Have you had time to un-tick the grid-charge blocks during the daytime slots? Did that make a difference?

17 minutes ago, Giel said:

I am in Pretoria  and my son in Somerset West. I hope the additional panels will be installed within a week or so. Then we will see if the response regarding the 500W is the same or not.

As myself and @GreenFields suggest the unticking grid use is quick and cost no moolas. 

35 minutes ago, Scorp007 said:

As myself and @GreenFields suggest the unticking grid use is quick and cost no moolas. 

I did untick the grid charge from 9h00 to 17h00, but had to put it back today as the sun was not that great in Cape Town area and there was more load due to house cleaning activities, doing washing, tumble drier, ironing, etc.

Will try again once extra panels are installed.

Grid charge ticked shouldn't make the PV drop as the inverter will prioritise using PV over grid. 

On 2024/05/15 at 4:18 PM, Giel said:

I did untick the grid charge from 9h00 to 17h00, but had to put it back today as the sun was not that great in Cape Town area and there was more load due to house cleaning activities, doing washing, tumble drier, ironing, etc.

Will try again once extra panels are installed.

If there is no load shedding then it is a waste to charge batteries from the grid. There are losses from the AC-DC DC-AC conversion and you will be wasting money. You can set SOC to 20% and use as much PV as you can on cloudy days. Grid will only be used once SOC is 20%.

This is the efficient way to do it without load shedding. When load shedding returns then adjust settings again. 

2 hours ago, Chris_S said:

Grid charge ticked shouldn't make the PV drop as the inverter will prioritise using PV over grid. 

What if as the OP mentioned little sun and your load is higher than PV can provide and you have ticked USING GRID to keep the battery between 30 to 45% during the 24hrs time settings? 

33 minutes ago, Scorp007 said:

What if as the OP mentioned little sun and your load is higher than PV can provide and you have ticked USING GRID to keep the battery between 30 to 45% during the 24hrs time settings? 

Still doesn't explain why the PV will drop when connecting to the grid. PV should always be at it's max when battery can be charged. 

Monday, if the weather permits, the number of PV panels will be increased to almpst double the PV capacity. I suspect that we will notice a significant improvement in yield from the current 4 east facing panels as this will be increased to 6. Then as mentioned above, another west facing string with 8 pnaels will be added. From Tuesday we will monitor this 500W power decreasing phenomenon again. If it still happens, we will do a number of things to find the cause namely:

1. A new confirmed legit, reputable installer is now contracted and will do the PV instalaltion on Monday. Maybe he can help Monday already, depending on the time of day they complete the installation. It could potentially be wiring or a setting.

2. If this persists and the cause is not identified, then I will go to a friend here in Pretoria and take screen shots of all the settings menus to compare.

3. If that does not identify the cause, then the position of the CT coil might be the cause. I suspect it is currently installed on the incoming mains in the DB box in the garage, next to the two 5kW inverters. If so, then maybe the metal box or inverters itself (EMI) or something might be interfering with the inductance of the coil and cause incorrect measurements. This is far fetched, but not impossible. I noticed with my installation (Mecer Axpert inverters) that the EMI from the inverters had an influence on the remote receiver of my alarm system. I had to move the remote receiver away from the inverters. If this is the case, then we will have to accept it as we might not find an alternative position to install it.