SolarpunkHomes
Sign inCall us · +44 7510 081687
Batteries
Batteries · Advice

Battery advice

Worth it or not, battery before solar, backup reserve, exporting from the battery, what happens in a long power cut — dated answers with their sources, generated from the research knowledge base.

Size your battery →14 answers · checked 24 September 2026
01

Is a home battery worth it in 2026?

Often, but not always. A battery pays when you have regular surplus solar, can charge cheaply overnight on a time-of-use tariff, or want backup.…

Read the answer →
02

Do I need solar panels to have a battery?

It can be, if you have a big gap between cheap and peak electricity prices and enough use in peak hours. The battery charges overnight and runs…

Read the answer →
03

What size home battery do I need?

Start from how much electricity you use outside your cheapest hours, not a single rule. EST says a typical home battery is about 10 kWh, and…

Read the answer →
04

How does a battery save money in winter?

Fill it on the cheapest overnight rate and let it carry the house through the day and the 4-7pm peak. With a 6-hour window at 7-9p and a battery…

Read the answer →
05

Which tariffs work with a home battery?

For most EV tariffs, yes. Octopus Go, Intelligent Octopus Go, EDF GoElectric, E.ON Next Drive and British Gas EV Power need an EV; Octopus's terms…

Read the answer →
06

Can I make money selling battery power to the grid?

Only on wide spreads. Buying at 8p and selling at 12p with a 90% round trip earns 3.1p per kWh, less than the battery wear of about 16–25p per…

Read the answer →
07

Will my battery work in a power cut?

Only if it was installed for backup. Grid-tied batteries must shut down when the grid fails unless an EPS or a backup gateway isolates the house.…

Read the answer →
08

Which battery chemistry is best?

For most homes, LFP (lithium iron phosphate). It dominates new UK home batteries, tolerates heat better, releases little oxygen in failure and is…

Read the answer →
09

Are cheap home batteries worth it?

Often, but for the software and support more than the cells. Most home batteries now use similar LFP cells; the differences are the battery…

Read the answer →
10

Should I charge my EV from my home battery?

Rarely. A 7 kW car charger can empty a 13.5 kWh battery in under two hours, and moving grid electricity through the battery into the car only adds…

Read the answer →
11

Batteries with a heat pump

It can be one of the better pairings. EST's July 2026 modelling found batteries save more alongside a heat pump than alongside solar, because the…

Read the answer →
12

Should I wait for battery prices to fall?

Cell prices have already fallen sharply - BloombergNEF found stationary storage packs dropped about 45% in 2025 to around $70/kWh - but…

Read the answer →
13

Home battery myths, checked against the evidence

It's a quick first guess for time-of-use tariffs, but it assumes you use the same power every hour. Real UK homes use more in the evening, so…

Read the answer →
14

Tesla Powerwall 3 vs SigenStor vs Fox Evo compared

All three are LFP-based hybrid systems with solar inputs. Powerwall 3 gives 13.5 kWh and up to 11.04 kW single-phase. SigenStor stacks 5.84 or…

Read the answer →