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Tesla Powerwall 3 for a small terrace in Southampton
Updated
A small terrace in Southampton needs a cupboard that meets the Tesla Powerwall 3 datasheet. Do not import a detached-house cabinet into Southampton just because the brand is familiar.
Tesla Powerwall 3 on a small terrace in Southampton
Southern yield helps the annual figure. It does not retire the winter tariff, which is the constraint I would write next to Tesla Powerwall 3 for this small terrace.
SSEN covers this Southampton example. A 4 kWp-class roof at 1040 kWh per kilowatt is about 6,240 kWh a year before shade, and Tesla Powerwall 3 does not change that weather.
Money for Tesla Powerwall 3 for a small terrace in Southampton
Take a 13.5 kWh pack, cycled about 340 times, at 90% round trip. Charge at 13.0p, and value what comes back at 30.8p. Export given up is priced at 12.0p. About 3213 kWh a year of the charge is treated as spare solar from 6 kWp that might otherwise have been exported. Delivered energy is about 4131 kWh. After charging cost and lost export, the sketch saves about £785 a year. Set that against £9,069 fitted, which is a September 2026 illustration at the temporary 0% residential rate, not a quote. That is a simple payback of about 11.6 years on these assumptions. Nudge the night rate up by 4p and see if you still like it.
Where the job is a qualifying install in a home, the 0% rate runs to 31 March 2027 and is due to become 5% after that. This sketch prices the work at £9,069 on that basis. It does not apply to a shop, and it does not apply to a battery you buy and fit yourself.
Connection for Tesla Powerwall 3 for a small terrace in Southampton
In Southampton, on SSEN, 5 kW sits above the 3.68 kW G98 line, so this wants a G99 application before anyone energises it. Export can still be capped. Agree that before the inverter is ordered. The sketch uses 13.5 kWh and 6 kWp, which is enough to tell two quotes apart if they assumed something else.
In Southampton, the weak case for Tesla Powerwall 3 is simple: Small evening loads, leasehold flats with nowhere legal to put a heavy cabinet, and budgets that only work if the pack is half this size.
Would I proceed with Tesla Powerwall 3 for a small terrace in Southampton?
I would not treat backup as included on a 13.5 kWh quote unless the circuits are listed.
I would proceed on Tesla Powerwall 3 for a small terrace in Southampton only after the cupboard, the 5 kW connection route and the tariff gap are written down.
Common questions
Is the price on this page a quote?
No. £9,069 is a September 2026 illustration for a 13.5 kWh example at the temporary 0% residential rate. Your survey replaces it.
Will it stay on in a power cut?
Only if a gateway or essential-load board was designed and paid for. A standard grid-tied battery turns off with the grid. On this 13.5 kWh sketch the inverter is 5 kW, and backup is still a separate line.
What paperwork should I keep?
Keep the MCS certificate where the job is certified, the electrical certificate, the DNO record, the schematic, the warranty registration and a photo of the schedule. For an illustrated £9,069 job, that folder is part of what you bought.
What if the cheap rate is not 7p?
Then the sketch changes. This page used 13.0p as a charge rate and 30.8p as the rate avoided. A smaller gap means a worse payback. Read the live tariff.
Sources
Want a price for your house?
The figures above are a rough guide. An installer still needs to see your fuse board, where the battery will go, and whether you want power during a blackout.