Battery storage
Battery storage is a control problem before it is a capacity number.
Battery capacity should be matched to how energy is generated, imported and consumed — whether the goal is self-consumption, tariff optimisation, peak management or resilience.
DEFINE THE JOB BEFORE THE CAPACITY
The right battery depends on what you want it to do at 18:00, 02:00 and during a peak.
Capacity alone does not tell you whether a battery suits the site. Usable energy, power, controls and operating strategy all matter.
01Capture solar surplus
If the objective is self-consumption, the design should start with likely surplus generation and evening demand rather than choosing kWh in isolation.
02Shift tariff periods
Cheap import windows can change how the battery is charged and discharged. The control strategy matters as much as the nominal capacity.
03Support peaks or resilience
High short-duration loads and backup expectations bring power limits, essential-load design and system architecture into the decision.
BATTERY DESIGN STACK
Capacity and power solve different problems.
A battery proposal should define the use case first, then size usable energy, charge/discharge power and control strategy around that objective.
Technical references: current MCS battery-storage guidance and Energy Networks Association connection standards.
BATTERY OBJECTIVE
Before choosing kWh, decide what the battery is meant to do.
The same nominal battery capacity can behave very differently depending on usable energy, charge and discharge power, controls, tariff strategy and how it integrates with solar or other site loads.
Capacity is not the whole specification. Ask what usable kWh is available, what continuous and peak power is supported, how the battery is controlled and what happens when the operating mode changes.
COMMON QUESTIONS
Questions worth answering before the equipment is fixed.
What is the difference between battery kW and kWh?
kWh describes how much energy can be stored or delivered over time. kW describes the rate at which the battery can charge or discharge at a given moment.
Does every battery provide whole-home backup?
No. Backup capability depends on the equipment, circuit design, changeover arrangement and configuration. It should be specified explicitly rather than assumed from battery capacity.
Can a battery charge from the grid as well as solar?
Many systems can, but the useful strategy depends on the equipment, controls, tariff and customer objective. The operating mode should be part of the design conversation.
STORAGE IN CONTEXT
Battery performance depends on the wider electrical system.
Match storage to the job it needs to do.
A useful battery proposal explains energy capacity, charging power, operating strategy and compatibility with the existing system.
How many usable kWh?
Battery capacity determines how much energy can be held; demand and usable operating limits determine how long it may last.
How many kW can it deliver?
Charge and discharge power, tariff scheduling and system controls affect when and how stored energy can be used.
New build or retrofit?
Check the existing inverter, metering, protection, monitoring and backup requirements before selecting a storage product.
CONNECTED ENERGY SYSTEM
Move between the parts of the system without starting over.
Solar generation, storage, EV charging and grid constraints affect each other. Use these routes to keep the project connected.
Get a home battery quote
Considering solar and storage together? Compare the EP6 and EP12 example home setups. For battery-only or retrofit work, tell us about your existing equipment so compatibility can be checked.