Solar & battery help - 3 elevations

[Ewan]

Finding it hard to chose between Solar Edge, Tigo Optimisers or EnPhase + AC coupled batteries.

Can anyone advise based on our layout? We won't get much shading apart from maybe the dormer.

I've had Solar Edge quoted, and EnPhase as an option, although this would require an AC coupled battery, which I understand you lose out on battery capacity as it needs to be inverted 3 times to use stored Solar energy, (or just twice from the grid, but that's the same with DC coupled I think).

Not sure what to go for. Also not sure I need Tigos on every panel (extra failure points?). Option A told me that 3 elevations means all need optimisers, while Option C have suggested only 2, and those are optional.

Quotes so far in detail:

Option A suggested 13 panels (one less on the East and West) - Tigos on every panel + 5kW Lux inverter (works with Octopus, a plus) with ~10kWh Pylon tech batteries (I like as it's expandable) - £12.2k
Option B suggested 15 panels as shown below  £12.5k, but currently a 3kW Sunsynk inverter & batteries of unknown type, TBC
Option C has run up a few quotes for me, including only 13 panels (but suggested against the rear ones as they're slightly north inclined) - only suggested Tigo optimisers on the East facing elevation due to the dormer =

- Solis 3.6kW Inverter (doesn't work with Octopus?) & 9.2kWh Pylon tech - £12.7k (only 2 Tigos)

- Givenergy 3kW inverter and 9.5kWh battery £13.5k

- Solar Edge - £16.5k

- EnPhase & GivEnergy 6kW / 13.5kWh AIO £16k


Any thoughts? it's all a bit overwhelming!

 

(this is Option B's suggestion)

[JohnMo]

Would also add to your list, the solar/inverter needs to work in a power cut. Most will not, or will give a a small dedicated output for say a lighting circuit. 

[SteamyTea]

What concerns me is that at £16k, you are replacing batteries and probably a micro inverter or two before you hit the break even point.

Fitting PV is probably worth it, really not sure if batteries are.

 

Would you be diverting excess PV to DHW storage?

Edited August 24, 2023 by SteamyTea

[Ewan]

I’ve been thinking that the batteries would be the star of the show! Keep the excess generation for later, and also charge up on cheap night rates in winter. 

can see the value in keeping the system costs down though. Perhaps the most simple one is the answer, no West aspect and less optimisers (just on the East face perhaps).

 

no divert yet, although maybe with the future heat pump. Although could just run the pump rather than divert to immersion. 

 

 

 

Edited August 24, 2023 by Ewan

[DougMLancs]

If your annual usage is below around 4000kWh then it’s a harder case for having batteries if you’re looking purely at ROI. Having said that we got a 9.5kWh battery with our install in May despite only using 2500kWh but we knew we were having an ASHP fitted and getting rid of the gas cooker. If you are planning your ASHP soonish then a battery now will make sense but otherwise you could retrofit one later. A Solar diverter didn’t make sense for us since it’s more cost effective to get an average DHW COP of 3-4 with our R290 ASHP and get paid for the export instead.

[Ewan]

Yes that's the thinking Doug. ASHP in the future, maybe bump the battery up to 15kWh at that point too. Induction hob going in, but previous to that our annual usage was 4600kWh.

Struggling with the configuration aspect more than anything. Think it boils down to these distinct options:

 

13/15 panels (if they fit) and Tigo on all

13/15 panels and Solar Edge (pricey)

10 panels and just one or two Tigos.

[JohnMo]

Optimisers don't work with all hybrid inverters if you go that route check.

 

You only really need optimises where you are likely to get shade.

 

 

[SteamyTea]

Have you run the different module configurations though PVGIS?

[Ewan]

55 minutes ago, JohnMo said:

Optimisers don't work with all hybrid inverters if you go that route check.

 

You only really need optimises where you are likely to get shade.

 

 

Or if your panels on one string are on different aspects, which is actually shade too I guess!

That would give one string with 3/4 panels on, and one with 10/11 panels over 2 aspects, and 2 or 3 optimisers on the smaller east facing roof. Seems like the simplest configuration..

Not tried PVGIS, will have a look at that.

 

[Dillsue]

Not sure if your drawing is to scale but it looks like you may be able to juggle panels on the south facing pitch and maybe those on the west to get an extra panel on each pitch?? If thats the case then move 2 panels off the east onto the south and west faces and use a dual MPPT inverter with one pitch on each MPPT input. Save the cost of optimisers.

 

Personally I'd go for a solaredge system but I can understand the concerns over the cost..... I would at £16k. Have you priced up the parts as that seems a hell of a price. 

[Conor]

Does look like you could get a few more panels on the south roof. Change that row of 6 portrait panels for two rows of 4 landscape. If you're using the likes of GSE trays, the. You can go right up to the ridge or into the gutter.

 

Can't comment on the main question but we've all solar edge stuff here and it's flawless.