MPP LVX6048 max Open circuit voltage in MPP online manual

[Badgerz]

Hello All
I am getting ready to install an MPP LVX4048, according to the manual on the MPP solar site <https://www.mppsolar.com/manual/SPLIT PHASE LV/LVX6048 manual-20220817.pdf>
it says on page 7
INVERTER MODEL LVX 6048
Max. PV Array Open Circuit Voltage 450 Vdc
PV Array MPPT Voltage Range 120~430Vdc

however on page 8 it gives an example of
Recommended PV module Configuration
PV Module Spec.
(reference)
- 250Wp
- Vmp: 30.7Vdc
- Imp: 8.15A
- Voc: 37.4Vdc
- Isc: 8.63A
- Cells: 60
Total solar input power Solar input Q'ty of modules
6000W 12 pieces in series
2 strings in parallel 24 pcs
which adds up to 448.8VDC, what happens when the temp gets cold, like 0 degrees F
wont the max voltage be exceeded ?
any thoughts?

 

[nc73]

I wouldn't go that close if I were you

 

[Eber]

I think you should write to MPP Solar and ask them about it. I know I would like to hear the answer from them.
This unit seems to have so many issues.

 

[jsheffer]

The high PV voltage is why I went with the lvx6048. It allows you to run more panels in a string. I wouldn't go 12 though. I'm running 6 370 watt in each string voltage runs around 230-250ish volts in the hot summer and closer to 300 volts in the cold winter. I live in the north side of utah so winter's get pretty cold here.

 

[Eber]

The high PV voltage is why I went with the lvx6048. It allows you to run more panels in a string. I wouldn't go 12 though. I'm running 6 370 watt in each string voltage runs around 230-250ish volts in the hot summer and closer to 300 volts in the cold winter. I live in the north side of utah so winter's get pretty cold here.

300 volts does leave you with quite a bit more you can go? Even with that gain of 50 volts, you have some room to play.

 

[nc73]

No combiner box needed. Saves a bit of dough.

 

[jsheffer]

you could try 3 strings of 8 in series...

 

[Badgerz]

I think you should write to MPP Solar and ask them about it. I know I would like to hear the answer from them.
This unit seems to have so many issues.

I emailed them on sept 13th, i received this reply sept 19th :
Dear Jim,

We wouldn’t recommend adding up to 448.8 VDC because it’s too close to the Max MPPT voltage.

As you mentioned, the temperature will affect the voltage and it depends on the PV temperature coefficient.

Please kindly reserve the buffer voltage to prevent damage.

Thank you and have a nice day.


Best Regards,

Vera Dai

vera.dai@mppsolar.com