New flat roof Array - Shading issue

martinW
Posts: 47
Joined: Tue Dec 28, 2021 5:35 am

Re: New flat roof Array - Shading issue

#11

Post by martinW »

smegal wrote: Thu May 19, 2022 10:39 am
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
Posts: 47
Joined: Tue Dec 28, 2021 5:35 am

Re: New flat roof Array - Shading issue

#12

Post by 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...
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nowty
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Location: South Coast

Re: New flat roof Array - Shading issue

#13

Post by nowty »

martinW wrote: Fri May 20, 2022 4:54 am 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.
16.9kW PV > 109MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 25MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 510 m3
martinW
Posts: 47
Joined: Tue Dec 28, 2021 5:35 am

Re: New flat roof Array - Shading issue

#14

Post by 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



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nowty
Posts: 5732
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: New flat roof Array - Shading issue

#15

Post by nowty »

As I have said before the inverter will simply current limit, don’t worry about the current.
16.9kW PV > 109MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 25MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 510 m3
MoSTiE
Posts: 70
Joined: Thu Sep 30, 2021 5:08 pm

Re: New flat roof Array - Shading issue

#16

Post by 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
Posts: 47
Joined: Tue Dec 28, 2021 5:35 am

Re: New flat roof Array - Shading issue

#17

Post by martinW »

nowty wrote: Sun May 29, 2022 11:24 am As I have said before the inverter will simply current limit, don’t worry about the current.
Tidy, thanks for that.
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