Deye Inverter, 80% voltage drop on switching on the PV switch. Is there any setting which must be changed?

[MichaelV37]

Dryer 8kw, new installation, having a big voltage drop on the PV, it is at 400v, but when you switch on the PV button on side of inverter, the voltage drops to 80v. 

1. Is it a setting issue?

2. Could it be polarity? 

 

[root]

That is exactly how it is supposed to work.

[Michael37]

Just trying to understand, how and why? Surely there shouldn't be such a drop, doesn't make sense as my limited experience that shows a short of some type?

[root]

Initially it measures the open circuit voltage. This is without any load on the panels. Once turned on it will pull the voltage down by allowing current to flow. The MPPT controller will dictate this voltage set point to maximise current flowing given the amount of light hitting the panels.

[Michael37]

on the Deye inverter, which setting can be set to get the maximum voltage and current? 

 

[root]

2 minutes ago, Michael37 said:

on the Deye inverter, which setting can be set to get the maximum voltage and current? 

 

There is no setting for this. This is the basic function of the MPPT controller (hardware). Meaning this is what it is designed and built to do. It 

[root]

Here is a picture. Notice how the blue (voltage from panels) goes down as the current (orange) increases. By midday my 15kWh battery bank is fully charged. The voltage shoots up by nearly 30V as the current falls to zero. The spikes later in the day is the geysers and the pool pump and other loads turning on and getting powered by the panels. Consequently voltage gets pulled down and current goes up again.

[Michael37]

but the voltage dropping from 400v to 80v is not correct, the inverter  does not show the PV at all.

[Scorp007]

7 minutes ago, Michael37 said:

but the voltage dropping from 400v to 80v is not correct, the inverter  does not show the PV at all.

This is totally abnormal for voltage to fall more than about 25%

If it drops to 80V it is too low for the MPPT so it could show no PV as you mention. 

Edited March 28, 2023 by Scorp007

[root]

Ah I misread, I thought it was dropping by 80V.

 

[P1000]

1 hour ago, MichaelV37 said:

1. Is it a setting issue?

2. Could it be polarity? 

1. No.

2. No.

It is either a shading issue (or heavy cloud coverage) or a wiring or panel issue.

[GreenFields]

Can you post pictures of your Solar details page on the inverter?

Showing the Voltage and current on PV1 and PV2.

And please confirm your panel specs and layout, ie. type and amount of panels, and if it's all on one MPPT?

[Michael37]

I am going to the installation, early evening. I will check all connections again and will take pics if I don't find anything physical.

Solar panel JA 455w x8 in series, one string. on one mppt.

 

[MichaelV37]

Where must the PV be connected on the PV 1. On connectors 1+2 or 1+3 ?

[MichaelV37]

Just done a check on all connections, if we test power coming from Deye inverter with the PV switch off (pic #1) no voltage. 

If we turn on Inverter PV switch there is 579 VDC coming back (pic #2)

[MichaelV37]

[MichaelV37]

Hi

[MichaelV37]

[Nexuss]

11 minutes ago, MichaelV37 said:

You have some serious issues here, Your battery cables are way too thin. The MPPT is wired wrong the black wire needs to be moved one slot left . The ct coil should not be in the inverter . You have no earth neutral bond relay . Your AC wires look too thin aswell.

Edited March 28, 2023 by Nexuss

[Scorp007]

1 hour ago, Nexuss said:

You have some serious issues here, Your battery cables are way too thin. The MPPT is wired wrong the black wire needs to be moved one slot left . The ct coil should not be in the inverter . You have no earth neutral bond relay . Your AC wires look too thin aswell.

I think you are making a mistake. The 2 wires to the MPPT are correct. 1st you get the 2xpos then 2xneg for MPPT1. Then the same for MPPT2. 

[Nexuss]

17 minutes ago, Scorp007 said:

I think you are making a mistake. The 2 wires to the MPPT are correct. 1st you get the 2xpos then 2xneg for MPPT1. Then the same for MPPT2. 

Thanks for the correction , do you agree with the rest ?

[JustinSchoeman]

MPPT is wired correctly. Likely cause of the reported issue is a poor connection (high resistance) somewhere in the panel string.

Agree on the rest: CT coil over there is definitely going to screw up power to non-essential loads (will not work at all).  Battery wires look like someone wants to light a bonfire. And AC wires certainly look too thin too. Lack of N-E bonding is a big safety issue.

[Scorp007]

2 hours ago, Nexuss said:

Thanks for the correction , do you agree with the rest ?

Yes 100%. But... We don't know what size battery is used. Same for MCB for essentials. 

[Chris_S]

Just by looking at the shody wiring in the inverter I would say you have a bad connection on your panel string. Possibly on an mc4 connection that is waiting to catch alight. 

When measuring 400VDC please wear some gloves. That shit can really arc

[Michael37]

On 2023/03/28 at 11:15 PM, Scorp007 said:

Yes 100%. But... We don't know what size battery is used. Same for MCB for essentials. 

It's a Shoto 5,12Kw lithium battery