Deye 8kW- how many panels per string

[joaa]

Dear Everyone,

I wish to install around 28 PV panels with a Deye 8kW single phase inverter, however the technician told me that the VOC is 500 volts per string, therefore I can't place more than 9 panels each string; is there any way I can put more?

 

[sunshine_eggo]

The tech is wrong as you can clearly see the string voltage can go as high as 800V with an MPPT operational range of 200-650V. Not sure what "full load DC voltage range" means, but I think you should target that range.

Assuming 500/9 = 55V or 50V per panel, so,

14 * 50 = 700V

If Voc of panels is 50V or less, then you should be good down to about -10°C based on conservative temperature coefficients.

This should put your series vmp around 600V, which is in the optimal range.

Two 14S strings, one on each MPPT seems viable as long as your panel Voc is 50V or less (maybe a little over is fine).

There might be other code or other components limitations, e.g., wire is only rated for 600V, or something like that. You'll just need to make sure everything used is rated to operate at 700V+.

 

[joaa]

The tech is wrong as you can clearly see the string voltage can go as high as 800V with an MPPT operational range of 200-650V. Not sure what "full load DC voltage range" means, but I think you should target that range.

Assuming 500/9 = 55V or 50V per panel, so,

14 * 50 = 700V

If Voc of panels is 50V or less, then you should be good down to about -10°C based on conservative temperature coefficients.

This should put your series vmp around 600V, which is in the optimal range.

Two 14S strings, one on each MPPT seems viable as long as your panel Voc is 50V or less (maybe a little over is fine).

There might be other code or other components limitations, e.g., wire is only rated for 600V, or something like that. You'll just need to make sure everything used is rated to operate at 700V+.

let's say i want to install 16 kw inverter instead of 2 inverter deye 8kw, how many panels i can get (VOC is 49v)

 

[sunshine_eggo]

7S2P per MPPT (assuming the same 28 panels)

8S is easy, 9S is possible down to about -8°C

These MPPT have 2X the current rating of the 8k unit, so you can parallel two strings.

 

[joaa]

7S2P per MPPT (assuming the same 28 panels)

8S is easy, 9S is possible down to about -8°C

These MPPT have 2X the current rating of the 8k unit, so you can parallel two strings.

Can I install 2x13Amp per string if the panels have an Isc of around 13 Amp? Thus, if I utilize 8 panels in one string for one mppt, I will obtain 72 pv panels in total.
in other term see the image below:

 

[sunshine_eggo]

No.

8S2P max per MPPT.

When you have 2P, you have two strings.

Two strings, 26A max per MPPT, 3 MPPT

A single 16k unit could handle 8S2P x3 = 48 panels. Anything more will be wasted.

The 13Ax2 is the maximum it can use. It allows up to 44A total on the next line of the specification.

Something that's not explicit, but is calculated from the specs:

rated voltage, 370V * 13A = 4810W/MPPT; 14,430W total

Also, 250A max output * 58V = 14,500W total

So no matter how much you put on it, up to the limits we've already discussed AND the 18,200W max DC input power, you will be limited to to something around 14,500W.

 

[Joehebbo]

Dear Everyone,

I wish to install around 28 PV panels with a Deye 8kW single phase inverter, however the technician told me that the VOC is 500 volts per string, therefore I can't place more than 9 panels each string; is there any way I can put more?

View attachment 137102

Not true it s better be 550 thats. Why they put 550 then (minimum and maximum 800) but to be safe 550 v

 

[Joehebbo]

Dear Everyone,

I wish to install around 28 PV panels with a Deye 8kW single phase inverter, however the technician told me that the VOC is 500 volts per string, therefore I can't place more than 9 panels each string; is there any way I can put more?

View attachment 137102

And by the way i have deye 8kw single phase the data sheet is not 550v is under that like 380 or 400 v i guess

 

[Joehebbo]

The tech is wrong as you can clearly see the string voltage can go as high as 800V with an MPPT operational range of 200-650V. Not sure what "full load DC voltage range" means, but I think you should target that range.

Assuming 500/9 = 55V or 50V per panel, so,

14 * 50 = 700V

If Voc of panels is 50V or less, then you should be good down to about -10°C based on conservative temperature coefficients.

This should put your series vmp around 600V, which is in the optimal range.

Two 14S strings, one on each MPPT seems viable as long as your panel Voc is 50V or less (maybe a little over is fine).

There might be other code or other components limitations, e.g., wire is only rated for 600V, or something like that. You'll just need to make sure everything used is rated to operate at 700V+.

No.

8S2P max per MPPT.

When you have 2P, you have two strings.

Two strings, 26A max per MPPT, 3 MPPT

A single 16k unit could handle 8S2P x3 = 48 panels. Anything more will be wasted.

The 13Ax2 is the maximum it can use. It allows up to 44A total on the next line of the specification.

Something that's not explicit, but is calculated from the specs:

rated voltage, 370V * 13A = 4810W/MPPT; 14,430W total

Also, 250A max output * 58V = 14,500W total

So no matter how much you put on it, up to the limits we've already discussed AND the 18,200W max DC input power, you will be limited to to something around 14,500W.

This is a pic shows 370 v the ideal and in (minimum and the max) but the best solution or option is 370 check the voc

 

[LydMekk]

I have the Deye 8kw myself.
Do NOT go over 400V total STC VoC (see the back on the panels, typical just under 50V per panel).
That makes each string 8 in series (400V) as the max charging on this models MPPT is 425V.

 

[Joehebbo]

I have the Deye 8kw myself.
Do NOT go over 400V total STC VoC (see the back on the panels, typical just under 50V per panel).
That makes each string 8 in series (400V) as the max charging on this models MPPT is 425V.

I have 2 series of 6 panels so i can add 4 more so 8 vs 8

 

[cods4]

I have the Deye 8kw myself.
Do NOT go over 400V total STC VoC (see the back on the panels, typical just under 50V per panel).
That makes each string 8 in series (400V) as the max charging on this models MPPT is 425V.

The OP is talking about a 3phase inverter which can support a higher Voc. I suspect yours is single phase.

 

[Joehebbo]

The OP is talking about a 3phase inverter which can support a higher Voc. I suspect yours is single phase.

Yes i am single phase 8 kw

 

[Muzzammild36]

I have the Deye 8kw myself.
Do NOT go over 400V total STC VoC (see the back on the panels, typical just under 50V per panel).
That makes each string 8 in series (400V) as the max charging on this models MPPT is 425V.

If max VoC is 500V then why stop at just 400V?

 

[houseofancients]

If max VoC is 500V then why stop at just 400V?

My 3 phase 12k is also a voc of 500..
Stay around 450v and make sure that no matter the temperature, you never exceed 500v or you will completely destroy you inverter

 

[LydMekk]

Ah...let him burn up his MPPT. Maybe then he'll learn. The hard way.

 

[Muzzammild36]

My 3 phase 12k is also a voc of 500..
Stay around 450v and make sure that no matter the temperature, you never exceed 500v or you will completely destroy you inverter

This is now cleared, thanks for making it clearer. Its reasonable to stay below 450V, I see no reason to stay below 400V as someone suggested somewhere above.

 

[shadowmaker]

I have been using 16S (47,7Voc, STC) with my Deye 12K 3-phase because Deye tech told me to do so. PV voltage in summer is usually around 600-700V, but at least two times last spring (-30C and sunrise) I witnessed it to go over 800V (809V highest), which resulted overcurrent protection and shut inverter down. When voltage dropped below 790V it started working normally again. Now I know better and will be changing both Deyes to 15S and add those panels to my 2x Bluesun 15K inverters as they have 1100V PV limit.