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Microinverter

Price

£144.99

The HMS-800W-2T Microinverter is designed for small solar systems, delivering reliable performance with an industrial-grade Wi-Fi module for seamless monitoring. With dual MPPTs, advanced safety features, and up to 800 VA output, it ensures efficient and secure solar power generation.

Quantity

Features

  • Designed for small solar systems such as balcony or garden.

  • Built-in industrial-grade Wi-Fi for reliable connection and monitoring.

  • Easy system management with S-Miles Cloud or Micro Toolkit app.

  • Output power customization for optimal performance.

  • Enhanced safety with rapid shutdown compliance and isolated transformer.

  • High power capacity with up to 1000 VA output (model-specific).

  • Manufacturer’s 12-year warranty

  • Free UK delivery

Compliance

  • IEC 61727, IEC 62116, IEC 61683
  • IEC60068-2-1/-2/-14/-30
  • EC/EN 62109-1/-2
  • IEC/EN 61000-6-1/-2/-3/-4
  • IEC/EN 61000-3-2/-3

Resources

Datasheet

20-Year Financial Projection

Storm 710W Solar Kit With Battery

System Size

0.71 kWp

4 × Storm 178W

Year 1 Generation

525 kWh

London estimate

Year 1 Savings

£298

At 30p/kWh

Payback Period

~5 Years

April '26 prices

20-year financial projection Chart With Battery.png
  • Year
    Elec rate (p/kWh)
    Generation (kWh)
    Self-use (kWh)
    Self-use savings (£)
    Battery arbitrage (£)
    Annual total (£)
    Cumulative (£)
    1
    30.00
    525
    525
    £157
    £140
    £298
    £298
    2
    30.90
    521
    521
    £161
    £144
    £305
    £603
    3
    31.83
    517
    517
    £165
    £149
    £313
    £916
    4
    32.78
    514
    514
    £168
    £153
    £322
    £1,238
    5
    33.77
    510
    510
    £172
    £158
    £330
    £1,568
    6
    34.78
    506
    506
    £176
    £163
    £339
    £1,907
    7
    35.82
    503
    503
    £180
    £167
    £348
    £2,254
    8
    36.90
    499
    499
    £184
    £172
    £357
    £2,611
    9
    38.00
    496
    496
    £188
    £178
    £366
    £2,977
    10
    39.14
    492
    492
    £193
    £183
    £376
    £3,353
    11
    40.32
    489
    489
    £197
    £188
    £386
    £3,738
    12
    41.53
    486
    486
    £202
    £194
    £396
    £4,134
    13
    42.77
    482
    482
    £206
    £200
    £406
    £4,540
    14
    44.06
    479
    479
    £211
    £206
    £417
    £4,957
    15
    45.38
    475
    475
    £216
    £212
    £428
    £5,385
    16
    46.74
    472
    472
    £221
    £218
    £439
    £5,824
    17
    48.14
    469
    469
    £226
    £225
    £451
    £6,275
    18
    49.59
    465
    465
    £231
    £232
    £463
    £6,737
    19
    51.07
    462
    462
    £236
    £239
    £475
    £7,212
    20
    52.61
    459
    459
    £241
    £246
    £487
    £7,699

  • Annual consumption: 2,700 kWh (Ofgem typical medium household). Winter 60% / Summer 40%.

    System: 4 x Storm 178W flexible solar panels (TopCon monocrystalline), total 0.71 kWp. Microinverter: Hoymiles HMS-800W-2T (800 VA, 2 MPPT, 96.7% peak efficiency).

    Orientation: Modelled at 90-degree vertical mounting (typical for fence or balcony railing). This is a conservative estimate. Tilting panels to a more favourable angle will increase generation.

    Year 1 generation: 525 kWh (estimated for London, based on typical balcony/fence mounting).

    Panel degradation: 2% in year 1, 0.7%/year thereafter (conservative estimate for flexible ETFE panels).

    Seasonal generation split: Winter 28% / Summer 72% (Thames region profile).

    Self-consumption rate: 100% year-round. System output is well below household demand, so all generation is consumed on-site.

    Electricity tariff: 30 p/kWh peak (average smart time-of-use daytime rate), 7 p/kWh off-peak (overnight rate), 3% annual inflation.

    Battery: Hoymiles HiBattery 1920 AC (HB-1920-AC-SV), 1.92 kWh usable capacity, LiFePO4 cells, AC-coupled, 87% round-trip efficiency, IP66, 6,000+ cycle life, 10-year warranty.

    Battery arbitrage: Off-peak grid charging at overnight rates, peak discharge during daytime. 365 days per year at full capacity (1.92 kWh). Solar generation is consumed directly by the household and does not charge the battery, leaving full battery capacity available for grid arbitrage year-round. Battery operates at 800W maximum output, sufficient to offset household base load during peak hours.
    87% round-trip efficiency.

Battery arbitrage savings assume the customer is on a smart time-of-use tariff with off-peak overnight rates. Actual returns may be higher or lower than projected
depending on tariff availability and usage patterns. All figures are estimates based on the assumptions above and should not be considered as guaranteed
returns.

20-Year Financial Projection

Storm 710W Solar Kit

System Size

0.71 kWp

4 × Storm 178W

Year 1 Generation

525 kWh

London estimate

Year 1 Savings

£131

At 25p/kWh

Payback Period

~5 Years

April '26 prices

20-year financial projection Chart.png
  • Year
    Elec rate (p/kWh)
    Generation (kWh)
    Self-use (kWh)
    Annual savings (£)
    Cumulative (£)
    1
    25
    525
    525
    £131
    £131
    2
    25.75
    521
    521
    £134
    £265
    3
    26.52
    517
    517
    £137
    £403
    4
    27.32
    514
    514
    £140
    £543
    5
    28.14
    510
    510
    £144
    £686
    6
    28.98
    506
    506
    £147
    £833
    7
    29.85
    503
    503
    £150
    £983
    8
    30.75
    499
    499
    £153
    £1,137
    9
    31.67
    496
    496
    £157
    £1,294
    10
    32.62
    492
    492
    £160
    £1,454
    11
    33.6
    489
    489
    £164
    £1,619
    12
    34.61
    486
    486
    £168
    £1,787
    13
    35.64
    482
    482
    £172
    £1,959
    14
    36.71
    479
    479
    £176
    £2,134
    15
    37.81
    475
    475
    £180
    £2,314
    16
    38.95
    472
    472
    £184
    £2,498
    17
    40.12
    469
    469
    £188
    £2,686
    18
    41.32
    465
    465
    £192
    £2,878
    19
    42.56
    462
    462
    £197
    £3,075
    20
    43.84
    459
    459
    £201
    £3,276

  • Annual consumption: 2,700 kWh (Ofgem typical medium household). Winter 60% / Summer 40%.

    System: 4 x Storm 178W flexible solar panels (TopCon monocrystalline), total 0.71 kWp. Microinverter: Hoymiles HMS-800W-2T (800 VA, 2 MPPT, 96.7% peak efficiency).

    Orientation: Modelled at 90-degree vertical mounting (typical for fence or balcony railing). This is a conservative estimate. Tilting panels to a more favourable angle will increase generation.

    Year 1 generation: 525 kWh (estimated for London, based on typical balcony/fence mounting).

    Panel degradation: 2% in year 1, 0.7%/year thereafter (conservative estimate for flexible ETFE panels).

    Seasonal generation split: Winter 28% / Summer 72% (Thames region profile).

    Self-consumption rate: 100% year-round. System output is well below household demand, so all generation is consumed on-site.

    Electricity tariff: 25 p/kWh (Ofgem price cap, April 2026), 3% annual inflation assumed.

Actual returns may be higher or lower than projected depending on tariff changes and usage patterns. All figures are estimates based on the assumptions above
and should not be considered as guaranteed returns.

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Setup Direction

Typically around £0.25–£0.29 per kWh

Energy production

  

kWh / year

Potential savings

  

£ / year

*Calculations are based on official solar radiation data from the European Commission's PVGIS database.

**Estimated production accounts for a 14% system loss and assumes a vertical panel angle (90° inclination).

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The Thunder Promise

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Free UK Delivery

Fast, tracked shipping at no extra cost.

10-Year Warranty

Microinverter guaranteed for a decade. Every component backed by its own warranty.

Expert Support

Free setup video call with every kit, plus ongoing support before, during, and after your purchase.

14-Day Returns

Not satisfied? Return your kit within 14 days for a full refund.

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