Home batteries are designed to fit domestic spaces, but some are larger and heavier than people expect.
Typical sizes:
- All-in-one units — Tesla Powerwall 3, for example, is 1105 × 609 × 193 mm and weighs 130 kg, and can be wall or floor mounted
- Modular units — some batteries are built from stackable modules, so the footprint depends on how much storage you choose
- Weight — wall mounting needs a wall that can take the load; heavier units are often floor mounted
Where a battery can go:
PAS 63100:2024, the fire-safety standard for batteries in homes, sets out where they can be installed (section 6.5):
- Outdoors where practicable — including an outbuilding not used for living in that meets the standard's separation requirement. Outdoor units must not be within 1 m of escape routes, doors, windows or ventilation openings, and a battery on an external wall must not compromise the wall's fire performance. Some models are rated for outdoor use, including Tesla Powerwall 3
- Indoors when outdoors isn't practicable — the location needs fresh-air ventilation to outdoors, and fire-resisting separation (at least 30 minutes) from the locations listed below
- Not allowed — rooms where people sleep; landings, staircases, corridors and other escape routes; cupboards or spaces that open into a bedroom; voids, roof spaces and lofts; within 2 m of stored flammable materials or fuel; and cellars or basements with no access to outside
- Smoke detection — a battery in a rarely visited place, such as a store cupboard, needs a smoke or multi-sensor alarm there, interlinked with the home's other alarms
So whether a garage, utility room or cupboard is suitable depends on that particular space: its ventilation, its separation from bedrooms and escape routes, and what it opens onto.
At the survey:
The proposed location is assessed against these requirements and the manufacturer's installation instructions, along with access and the weight of the unit.
