Advice on risk of PV overvoltage

[dimsum2]

Hi guys,

I'm looking to replace my inverter from a GoodWe GW10K-MS which has a Max input voltage of 600v and MPPT operating Voltage of 80 - 550.

I want to move to a Deye SUN-16K-SG01LP1-AU which has a lower operating voltage of PV input V 125 - 500v and MPPT Range 150-425v.

I have two strings of 25 x 400w Trina panels so 14 panels and 11panels in series so the design does exceed Deye's max. Looking at the past 3-4 months though my voltage rarely goes above 500v.

Can I keep my panels connected as is or should I redo configuration?

Thanks!

 

[seneysolar]

Max pv voltage is never exceed. Not even once.

Reconfigure will be required

Edit: use the panels rated Voc and temp coefficient for your coldest temp to calculate your possible max voltage. Do not bump up against the charge controller max voltage, they dont like it, at all.

 

[dimsum2]

Max pv voltage is never exceed. Not even once.

Reconfigure will be required

Edit: use the panels rated Voc and temp coefficient for your coldest temp to calculate your possible max voltage. Do not bump up against the charge controller max voltage, they dont like it, at all.

Appreciate your help, just did the calculations and 11 panels has a max voltage of 480v at lowest temp. So it seems I'll have to split the 14 panel string. Should I remove 3 panels or split it to 2 x 7 panels? I'm assuming having 7 panels means it'll drop below lowest voltage sooner which isn't ideal.

 

[seneysolar]

Appreciate your help, just did the calculations and 11 panels has a max voltage of 480v at lowest temp. So it seems I'll have to split the 14 panel string. Should I remove 3 panels or split it to 2 x 7 panels? I'm assuming having 7 panels means it'll drop below lowest voltage sooner which isn't ideal.

2x7 should be better than loosing 3 panels worth of watts.
What are the panel specs?

 

[dimsum2]

The Trina 400w panel details are:

Voc at STC: 41.4
Temp Coef of VOC: - 0.25%/°C

Yeah I'd rather not remove 3 panels just not sure if that means 7 panels will reach minimal voltage sooner.

 

[seneysolar]

The Trina 400w panel details are:

Voc at STC: 41.4
Temp Coef of VOC: - 0.25%/°C

Yeah I'd rather not remove 3 panels just not sure if that means 7 panels will reach minimal voltage sooner.

View attachment 207184

7 panels in series will hit 150v very quickly, you likely wont notice the difference.

With Vmpp of 34.2, you could go down to 5S before youd have any issues with mppt functionality.

 

[shadowmaker]

16K has three MPPTs so 9S+8S+8S. If you don't get low temperatures then it might be easier to keep current 11S for MPPT1 and parallel 14S to two strings of 7S for MPPT2. Then you have one MPPT left for adding more panels.

 

[Brett V]

16K has three MPPTs so 9S+8S+8S.

This would be my choice if in your position. You’ll need 3 combiners and appropriately sized wire to the mppt inputs so the cost just went up, but not only do you get your voltage in the sweet spot, but you have redundancy in case of a problem with one of the strings. Any shading on a single panel will also have less of an impact.