RaviVolt Roof Solar Calculatorv1.3.1

Thailand 5°–20° N · AIKO 650 W bifacial · PVGIS-ERA5 yield · MEA tariffs · live recompute

Inputs on the left → results recompute live. Methodology: /info-hub

Step 0

Where is your roof?

Street address, condo, or building name

We use Google's Solar API to read your actual roof — area, tilt, and orientation. Your address is only sent to Google for the lookup; we never store it without your lead form.

Step 1

Your roof

Roof typeRoof area (usable)

m²

Floor footprint of the roof you'd use for solar — exclude AC units, skylights, antennae.Roof orientation (which way the panels face)

Roof tilt (pitch from horizontal)

0 °5 °45 °

0153045

Bangkok optimum is 15–17° south. Flat slabs default to 5° rear-tilt racks.Shading

Step 2

Your consumption

How do you know your usage?

Average monthly electricity bill

฿/mo

Tariff scheduleDaytime share of load — 40%

10 %40 %90 %

1030507090

Roughly how much of your usage happens between 9am and 6pm. Higher = better direct self-consumption, less battery value.

Step 3

Battery storage

Add battery storageStores midday surplus and discharges during the evening peak window. Boosts savings on TOU tariffs; less useful when load is daytime-heavy.Battery capacity — 10 kWh (recommended 15)

7.5 kWh10 kWh20 kWh

Sized to absorb ~14 kWh of midday PV surplus and discharge into the evening peak window.

Expected cycles

329/yr

Unserved peak

2.4 MWh

Step 4

Financing

How will you pay?

Override CapEx defaults →

System ฿/kWp

฿

Battery ฿/kWh

฿

System size

14.4 kWp

20.4 MWh/yr

Annual savings

฿65k

44% self-consumed

Cash payback

11.3 yr

CapEx ฿754k

25-yr NPV

฿32k

IRR 8.4%

Roof preview

Layout is illustrative — final placement depends on roof geometry and obstruction survey.

Monthly generation

24-hour shape — generation vs load

Generation Load → battery battery → Peak window

25-year cumulative cashflow

Cash

Send me this analysis

We'll email you the full numbers and a sales engineer will follow up within one business day with a no-obligation site visit offer.

How we calculated this →

Solar yield. Specific yield is read from a Bangkok-anchored matrix (8 tilts × 6 azimuths) derived from PVGIS-ERA5 with a Klucher diffuse + Hay isotropic ground-reflection model at 13.9°N. Reference cell: 17° south = 1,456 kWh/kWp/yr after the full 0.845 tropical loss chain. v1.3.0 generalises across 5 Thai latitude bands (5°–20°N) — see thailand_roof_yield_matrix.md.

Modules. AIKO 650 W Bifacial ABC, 24.07 % efficiency, 2.701 m² per panel. Bifacial gain on roof flush-mount limited to 2.5 % (rear face within ~10 cm of roof skin). Switch to monofacial in advanced settings if you're being quoted older silicon.

Tariffs. MEA 2026 schedules — residential 1.1 (flat 4.40 ฿/kWh blended) and 1.2 (TOU 5.79 / 2.63), commercial type 3 TOU (4.18 / 2.63). Buy-back 2.20 ฿/kWh under VSPP self-consumption. Annual tariff escalation 3 %.

Battery dispatch. Greedy hourly simulator — PV → load first; surplus charges battery up to 0.5C; deficit discharges battery (peak hours preferred), grid covers the rest. Round-trip 0.92, depth-of-discharge 0.90.

CapEx. Anchored on the Phoem Sin 8-rai ground-mount memo (22 ฿/Wp turnkey), with a roof-racking premium — house 35,000 ฿/kWp, townhouse / villa 38,000 ฿/kWp, commercial 30,000 ฿/kWp, large commercial (>100 kWp) 25,000 ฿/kWp. LiFePO4 batteries 25,000 ฿/kWh residential, 22,000 ฿/kWh commercial. All overridable.

Financing. Defaults — house GSB Solar Secured 3.25 % / 7 yr / 80 % LTV; townhouse GSB Unsecured 3.50 % / 7 yr; commercial SCB Sustainable Business 3.25 % / 10 yr / 50 % LTV. Source: thai-bank-loan-options.md.

25-year economics. 0.5 % / yr panel degradation, 1.5 % of system CapEx / yr O&M, 8 % discount rate for NPV.

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