New flat roof Array - Shading issue

[martinW]

I struggled to find a domestic inverter happy with the VOC and ISC of large panels. It's worth confirming this before you go too far. That said, I didn't look too hard, and was very reliant on what PVSol Software had to say on the matter.

Solax X1 2.0kW inverter VMPP 55-380v So If I went for 4 or 5 of the 440watt panels it would be around 160v-200v so no worries.

[martinW]

Just had a thought, low volts might be ok, but High DC current might not... need to check proposed panel current output against what the inverter can take...


told you it was a while since I looked into these things...

480watt panels are around 11amp. so looks like they'd be ok...

545watt panels are 13.0 amps, so 'could' be a problem with some inverters...

[nowty]

Just had a thought, low volts might be ok, but High DC current might not... need to check proposed panel current output against what the inverter can take...


told you it was a while since I looked into these things...

480watt panels are around 11amp. so looks like they'd be ok...

545watt panels are 13.0 amps, so 'could' be a problem with some inverters...

Its voltage which kills inverters, not the current, they simply current limit and work at a slightly higher panel voltage. Your hardly ever going to get full current with a flat roof installation because the angle to the sun is never optimum.

[martinW]

More on max current.

Been looking at JA SOlar 545 watt panels which have a max current of 13.04A and Short Circuit current of 13.93 Amps.

My proposed inverter is 12Amps and 15amps... So the Short circuit is ok, but the running amps is theoretically too high.

However,

Looking at the Data sheet for the panel (attached) it looks like the panel will only output around 11amps at 800w/m2 irradiance. As I'm in Wales would I be correct in that we would not get any sun levels above this anyways... I thought 1000W/m2 was basically at the equator

[nowty]

As I have said before the inverter will simply current limit, don’t worry about the current.

[MoSTiE]

I've got 2.4kw connected to an old Sunnyboy 1700, it just goes to 1710W and stays there, if it gets hot it goes down a bit.

[martinW]

As I have said before the inverter will simply current limit, don’t worry about the current.

Tidy, thanks for that.