Quote check: 8.1 kWp Trina + 10 kWh Fox battery for £11.5 k – 20 p SEG… sound about right?

Batch_2

Considering solar with battery. I've approached OVO as I like their overnight EV charging and 20 p SEG if I order the panels and battery through them. Can I get your thoughts on this please?

Quick background

• Location: Gloucestershire (two-storey house).

• Roof: Main south-facing pitch ≈ 27 °, 9 ° E of due S; clay tiles, clear of big shade except chimney.

• Annual demand: Smart-meter shows ~9,900 kWh / yr (of which about 50% is EV charging overnight on 7p OVO EV tariff).

• Goals: Max out the roof, keep export flexible, payback not too far in the future.

---

Quote I’m reviewing

Item	Spec
Installer	OVO Solar & Heating – South Wales (MCS-registered franchise of OVO Energy)
PV array	18 × Trina Vertex S+ 450 W (dual-glass, N-type, all-black) → 8.10 kWp
Inverter	Fox ESS KH-7 kW single-phase hybrid (3 MPPT, 10-yr warranty)
Battery	Fox ESS EP11 — 10.4 kWh LFP, DC-coupled, 10-yr / 6,000 cycle warranty
Price	£11,450 all-in (0 % VAT, scaffold included)
Warranty	Panels 25 yr product / 30 yr performance, inverter 10 yr, battery 10 yr; workmanship only 2 yrs (trying to get 5 yrs or IBG)
Export tariff	OVO “Install Exclusive” 20 p/kWh SEG (must take OVO import supply)
Paperwork	G-99 promised for the full 7 kW export; MCS + HIES; deposit 20 % then 80 % on completion

---

Pros I see

• Competitive £/kWp.

• Tier-1 dual-glass Trinas + LFP pack should age well.

• Hybrid inverter leaves DC port free for extra battery stack later.

• 20 p SEG looks attractive - if OVO honour it long-term.

Concerns / open questions

1. Workmanship cover only 2 yrs – I'll try pushing for 5 yrs or independent IBG.

2. Need written proof the G-99 will allow full 7 kW export (no firmware cap).

3. Mounting kit corrosion class (C4?) & structural calcs for 1980s truss roof.

4. Battery settings — DoD %, time-of-use charging, grid-backup capability.

5. What happens if I leave OVO for import – does SEG stay or drop to default?

Screwdriva

Pros I see

• Competitive £/kWp.

• Tier-1 dual-glass Trinas + LFP pack should age well.

• Hybrid inverter leaves DC port free for extra battery stack later.

• 20 p SEG looks attractive - if OVO honour it long-term.

Concerns / open questions

1. Workmanship cover only 2 yrs – I'll try pushing for 5 yrs or independent IBG.

2. Need written proof the G-99 will allow full 7 kW export (no firmware cap).

3. Mounting kit corrosion class (C4?) & structural calcs for 1980s truss roof.

4. Battery settings — DoD %, time-of-use charging, grid-backup capability.

5. What happens if I leave OVO for import – does SEG stay or drop to default?

Sorry to share, I think you've been mis-sold the pros.

1) Trina is nowhere close to "Tier 1", whatever that means. Of all the panel brands on the market, I've heard/ read the most complaints about Trina/ Longhi

2) 20p via OVO is good but Octopus Intelligent Flux pays much more for export in your area. 

~£12.7K will get you:

18 X Eurener 500W Bifacial (dual glass panels) -> 9kWp system size (vs. 8.1)
  1 X Tesla PW3 with Gateway 2 -> 13.5kW battery capacity with 8kW inverter.

10 year workmanship warranty & bird netting included. G99/ HIES included. 

That's 10% more PV generation from a European panel brand, 30% more storage and a 14% larger inverter size to capitalize on it. Then there's the PW3's unmatched safety, performance, whole house backup and software (vs. Fox, which is a budget brand). 

I hope this highlights that you can do much better! 

Reed_Richards

Screwdriva said:

Pros I see

• Competitive £/kWp.

• Tier-1 dual-glass Trinas + LFP pack should age well.

• Hybrid inverter leaves DC port free for extra battery stack later.

• 20 p SEG looks attractive - if OVO honour it long-term.

Concerns / open questions

1. Workmanship cover only 2 yrs – I'll try pushing for 5 yrs or independent IBG.

2. Need written proof the G-99 will allow full 7 kW export (no firmware cap).

3. Mounting kit corrosion class (C4?) & structural calcs for 1980s truss roof.

4. Battery settings — DoD %, time-of-use charging, grid-backup capability.

5. What happens if I leave OVO for import – does SEG stay or drop to default?

 

2) 20p via OVO is good but Octopus Intelligent Flux pays much more in your area. 

I think @Screwdriva must have missed your comment about EV charging, I don't think Octopus Intelligent Flux is suitable for that.  And I think the 20p/kWh import rate requires you to remain as an OVO customer for import; read the T&Cs carefully and you'll probably find that. 

Avallon_2

Screwdriva said:

Pros I see

• Competitive £/kWp.

• Tier-1 dual-glass Trinas + LFP pack should age well.

• Hybrid inverter leaves DC port free for extra battery stack later.

• 20 p SEG looks attractive - if OVO honour it long-term.

Concerns / open questions

1. Workmanship cover only 2 yrs – I'll try pushing for 5 yrs or independent IBG.

2. Need written proof the G-99 will allow full 7 kW export (no firmware cap).

3. Mounting kit corrosion class (C4?) & structural calcs for 1980s truss roof.

4. Battery settings — DoD %, time-of-use charging, grid-backup capability.

5. What happens if I leave OVO for import – does SEG stay or drop to default?

Sorry to share, I think you've been mis-sold the pros.

1) Trina is nowhere close to "Tier 1", whatever that means. Of all the panel brands on the market, I've heard/ read the most complaints about Trina/ Longhi

2) 20p via OVO is good but Octopus Intelligent Flux pays much more for export in your area. 

~£12.7K will get you:

18 X Eurener 500W Bifacial (dual glass panels) -> 9kWp system size (vs. 8.1)
  1 X Tesla PW3 with Gateway 2 -> 13.5kW battery capacity with 8kW inverter.

10 year workmanship warranty & bird netting included. G99/ HIES included. 

That's 10% more PV generation from a European panel brand, 30% more storage and a 14% larger inverter size to capitalize on it. Then there's the PW3's unmatched safety, performance, whole house backup and software (vs. Fox, which is a budget brand). 

I hope this highlights that you can do much better! 

Trina are a Tier 1 supplier. It's a measure by Bloomberg of the company's financial stability and ability to fulfil contracts. It's not a measure of product quality.

Avallon_2

Batch_2 said:

Considering solar with battery. I've approached OVO as I like their overnight EV charging and 20 p SEG if I order the panels and battery through them. Can I get your thoughts on this please?

Quick background

• Location: Gloucestershire (two-storey house).

• Roof: Main south-facing pitch ≈ 27 °, 9 ° E of due S; clay tiles, clear of big shade except chimney.

• Annual demand: Smart-meter shows ~9,900 kWh / yr (of which about 50% is EV charging overnight on 7p OVO EV tariff).

• Goals: Max out the roof, keep export flexible, payback not too far in the future.

---

Quote I’m reviewing

Item	Spec
Installer	OVO Solar & Heating – South Wales (MCS-registered franchise of OVO Energy)
PV array	18 × Trina Vertex S+ 450 W (dual-glass, N-type, all-black) → 8.10 kWp
Inverter	Fox ESS KH-7 kW single-phase hybrid (3 MPPT, 10-yr warranty)
Battery	Fox ESS EP11 — 10.4 kWh LFP, DC-coupled, 10-yr / 6,000 cycle warranty
Price	£11,450 all-in (0 % VAT, scaffold included)
Warranty	Panels 25 yr product / 30 yr performance, inverter 10 yr, battery 10 yr; workmanship only 2 yrs (trying to get 5 yrs or IBG)
Export tariff	OVO “Install Exclusive” 20 p/kWh SEG (must take OVO import supply)
Paperwork	G-99 promised for the full 7 kW export; MCS + HIES; deposit 20 % then 80 % on completion

---

Pros I see

• Competitive £/kWp.

• Tier-1 dual-glass Trinas + LFP pack should age well.

• Hybrid inverter leaves DC port free for extra battery stack later.

• 20 p SEG looks attractive - if OVO honour it long-term.

Concerns / open questions

1. Workmanship cover only 2 yrs – I'll try pushing for 5 yrs or independent IBG.

2. Need written proof the G-99 will allow full 7 kW export (no firmware cap).

3. Mounting kit corrosion class (C4?) & structural calcs for 1980s truss roof.

4. Battery settings — DoD %, time-of-use charging, grid-backup capability.

5. What happens if I leave OVO for import – does SEG stay or drop to default?

Batch_2 said:

Considering solar with battery. I've approached OVO as I like their overnight EV charging and 20 p SEG if I order the panels and battery through them. Can I get your thoughts on this please?

Quick background

• Location: Gloucestershire (two-storey house).

• Roof: Main south-facing pitch ≈ 27 °, 9 ° E of due S; clay tiles, clear of big shade except chimney.

• Annual demand: Smart-meter shows ~9,900 kWh / yr (of which about 50% is EV charging overnight on 7p OVO EV tariff).

• Goals: Max out the roof, keep export flexible, payback not too far in the future.

---

Quote I’m reviewing

Item	Spec
Installer	OVO Solar & Heating – South Wales (MCS-registered franchise of OVO Energy)
PV array	18 × Trina Vertex S+ 450 W (dual-glass, N-type, all-black) → 8.10 kWp
Inverter	Fox ESS KH-7 kW single-phase hybrid (3 MPPT, 10-yr warranty)
Battery	Fox ESS EP11 — 10.4 kWh LFP, DC-coupled, 10-yr / 6,000 cycle warranty
Price	£11,450 all-in (0 % VAT, scaffold included)
Warranty	Panels 25 yr product / 30 yr performance, inverter 10 yr, battery 10 yr; workmanship only 2 yrs (trying to get 5 yrs or IBG)
Export tariff	OVO “Install Exclusive” 20 p/kWh SEG (must take OVO import supply)
Paperwork	G-99 promised for the full 7 kW export; MCS + HIES; deposit 20 % then 80 % on completion

---

Pros I see

• Competitive £/kWp.

• Tier-1 dual-glass Trinas + LFP pack should age well.

• Hybrid inverter leaves DC port free for extra battery stack later.

• 20 p SEG looks attractive - if OVO honour it long-term.

Concerns / open questions

1. Workmanship cover only 2 yrs – I'll try pushing for 5 yrs or independent IBG.

2. Need written proof the G-99 will allow full 7 kW export (no firmware cap).

3. Mounting kit corrosion class (C4?) & structural calcs for 1980s truss roof.

4. Battery settings — DoD %, time-of-use charging, grid-backup capability.

5. What happens if I leave OVO for import – does SEG stay or drop to default?

you would lose the SEG if you leave OVO for import. For a big company the price isn't far out, but it's not great value. You'd be better off with a system as described by Screwdriver or look for alternative suppliers who should be able to supply a similar system more cheaply or with 18ish kWh battery capacity.