SOLAR + BATTERY — LIVE CALCULATOR

Edit the numbers as your quotes come in

Same model as before — your real half-hourly usage plus a modelled dispatch simulation — but every input below is editable, and it recalculates instantly. Switch between a full solar+battery system and a battery-only option.

Modelled generation
3,709 kWh/yr
≈48% of annual use
Bill after system
£584 /yr
was £1,811/yr
Gross annual saving
£1,227 /yr
bill cut + export income
Cash payback
6.5 years
if bought outright
Step 1 — your usage

Upload your own half-hourly usage

Works with a half-hourly (or hourly) usage export from any supplier or smart-meter app — see the format guide below for what's needed. Everything below then recalculates against your real usage pattern instead of the example.

EXAMPLE DATA Using example usage data (7,715 kWh/yr, one year, half-hourly)
Off-peak tariff

Have a cheaper overnight rate (EV tariff, Economy 7, etc.)? If not — e.g. no EV and a standard single-rate tariff — turn this off.

Off-peak window switched off — every kWh is now costed at your single (peak) rate, matching a standard flat tariff with no cheap overnight window.
Step 2 — your quote

Plug in each quote as you get it

Everything below recalculates live. Panel count, wattage and yield only apply in Solar + Battery mode.

System — panels

W
kWh/kWp/yr
Array size: 3.84 kWp

Battery

kWh
% each way

Cost & financing

£
£
%
mo mo

Tariff & rates

p/kWh
p/kWh
p/day
p/kWh
Where the energy actually goes

A year of your electricity, rebalanced

Modelled from your real half-hourly usage pattern and the inputs above.

Your solar generation is used for…100%
Your annual demand is met by…100%
Monthly breakdown

Generation, usage and cost across the year

Consumption vs. solar generation

kWh per month

Monthly bill: before vs. after

£ per month, before export income is applied to the loan
Before
After (net)
Year one, in full

Annual cost breakdown

Off-peak import
£567
5,968 kWh
Peak import
£50
150 kWh
Standing charge
£193
unaffected by system size
Export income
£226
1,886 kWh
Line itemBeforeAfterChange
The loan — both terms compared

Financing

£7,950 cash price, £100 deposit, £7,850 financed at 9.9% APR.

60-month term
£164.78 /month
120-month term
£101.48 /month
The long view

Cumulative cost vs. doing nothing

Deposit + loan + electricity bills − export income (if any), against carrying on paying today's rates with no system. Assumes flat tariffs for 20 years.

No system (baseline)
Term A
Term B
Term A breaks even
Year 8
Term B breaks even
Year 10
Full detail

Month-by-month numbers

MonthUsageSolarExported Off-peak costPeak costStanding Bill (pre-export)Export creditNet costWould've been