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Existing is a 15 panel 2 strings of 265 watt (3975watt into a 3.6kW Power One inverter 2012) Close to due south facing roof at40 degree pitch.
Thinking of upgrade to 11 new 560watt panels, 7 panels of 2 unequal strings = 3920 watt to keep exising fit with a new 3.6kW Hybrid inverter and
battery pack of at least 10Kwh.
4 remaining new panels of 2240watt into a single string 2.0 kW inverter with isolaters and a new generation meter.
Upgrade through G99 with a request to add additional 2 kW of export to existing. (6 kW export in total)

Any thoughts advice and recommendations welcome!

Comper wrote: ↑Wed Jan 29, 2025 5:16 pm Existing is a 15 panel 2 strings of 265 watt (3975watt into a 3.6kW Power One inverter 2012) Close to due south facing roof at40 degree pitch.
Thinking of upgrade to 11 new 560watt panels, 7 panels of 2 unequal strings = 3920 watt to keep exising fit with a new 3.6kW Hybrid inverter and
battery pack of at least 10Kwh.
4 remaining new panels of 2240watt into a single string 2.0 kW inverter with isolaters and a new generation meter.
Upgrade through G99 with a request to add additional 2 kW of export to existing. (6 kW export in total)

Any thoughts advice and recommendations welcome!

Good idea. However you'd benefit from putting panels on your north-facing roof too.

Stinsy wrote: ↑Wed Jan 29, 2025 5:19 pm

Comper wrote: ↑Wed Jan 29, 2025 5:16 pm Existing is a 15 panel 2 strings of 265 watt (3975watt into a 3.6kW Power One inverter 2012) Close to due south facing roof at40 degree pitch.
Thinking of upgrade to 11 new 560watt panels, 7 panels of 2 unequal strings = 3920 watt to keep exising fit with a new 3.6kW Hybrid inverter and
battery pack of at least 10Kwh.
4 remaining new panels of 2240watt into a single string 2.0 kW inverter with isolaters and a new generation meter.
Upgrade through G99 with a request to add additional 2 kW of export to existing. (6 kW export in total)

Any thoughts advice and recommendations welcome!

Good idea. However you'd benefit from putting panels on your north-facing roof too.

+1 to that. I’m getting about 50% on a north facing roof over a year. With the price of panels being so low it makes sense to do so - IMO

Is that with another inverter or just adding to existing?

drjim wrote: ↑Wed Jan 29, 2025 7:54 pm Is that with another inverter or just adding to existing?

You can do what you like!

I’d suggest having a FiT inverter going through the FiT meter then have a hybrid inverter with 2x MPPTs one with a single string on your south roof and 2x strings on your North roof paralleled up into the 2nd MPPT.

Without wanting to derail the original thread I have a WNW facing large roof that has zero shading issues and should fit 16 panels which would be an interesting addition to 8 ESE facing panels on the other side of the ridge....

drjim wrote: ↑Wed Jan 29, 2025 8:34 pm Without wanting to derail the original thread I have a WNW facing large roof that has zero shading issues and should fit 16 panels which would be an interesting addition to 8 ESE facing panels on the other side of the ridge....

Go for it!

I would second that my 3.6kWp West array does very well for us.

Moxi

Comper wrote: ↑Wed Jan 29, 2025 5:16 pm Existing is a 15 panel 2 strings of 265 watt (3975watt into a 3.6kW Power One inverter 2012) Close to due south facing roof at40 degree pitch.
Thinking of upgrade to 11 new 560watt panels, 7 panels of 2 unequal strings = 3920 watt to keep exising fit with a new 3.6kW Hybrid inverter and
battery pack of at least 10Kwh.
4 remaining new panels of 2240watt into a single string 2.0 kW inverter with isolaters and a new generation meter.
Upgrade through G99 with a request to add additional 2 kW of export to existing. (6 kW export in total)

Any thoughts advice and recommendations welcome!

Hiya. I think your plan is probably best, if you plan on adding that DC side battery.

You could run it all through a new and larger inverter, and get the FiT apportioned. That's what I've done. But .... if the battery is DC side, then for FiTs you'll need to change the TGM for a bi-directional meter, and because of battery losses, you'll end up with a small net loss to generation (and FiTs), if charging the battery from the grid in winter (as I do). Eg, if you charged 10kWh at night, the TGM would record -10, then when you use that and get say 8kWh out, it will record +8, and the net reading will have gone down 2.

Edit - Sorry, misread, I see the DC battery is on the FiT string. In that case better to put it all through one inverter*, or go with an AC side battery, and keep the old TGM, and no net losses.

*If you have a DC side battery, then you'll be able to have a lower powered inverter, if the DNO won't give you a higher export limit. My 3.68kW inverter can also redirect upto 5kW DC to the batts, so no clipping from the 6.7kWp PV, so long as there is space in the batts.

Many thanks for your comments and advice.
Regarding east west and north elevations they are not pracical due to valleys and smaller roof areas.
I thought upgrading existing to as close as original would give greater uplift due to newer panels being considerably more efficient and my older panels may have lost 10% + or - over13 years.
One question can anyone identify this mounting system below as hoping to reuse the mounting brackets and attach new rails and clamps.