Tiny home batteries: LiFePO4, sizing and home battery vs power station
Updated 4 Nov 2026. The battery stores your solar power for night-time and cloudy days. Here's how to pick the chemistry and size.
1. Chemistry
- LiFePO4 (LFP): the usual choice today. Often rated for thousands of cycles, it's more thermally stable than other lithium types and can be used deeply (about 80 to 100%). Most can't charge below about 0 °C unless they have built-in heating.
- NMC lithium: lighter, but usually fewer cycles. It's common in older power stations.
- Lead-acid (AGM or flooded): cheapest up front, but heavy, and you should only use about 50% of it regularly.
2. Sizing in kWh
Battery kWh ≈ daily kWh × days of autonomy ÷ usable depth (about 0.9 for LFP).
| Daily use | 1 day | 2 days | 3 days |
|---|---|---|---|
| 2 kWh | ~2.2 kWh | ~4.4 kWh | ~6.7 kWh |
| 4 kWh | ~4.4 kWh | ~8.9 kWh | ~13.3 kWh |
| 6 kWh | ~6.7 kWh | ~13.3 kWh | ~20 kWh |
All figures on this page are estimates for planning. Real use depends on climate, appliances and habits.
On-grid or with a generator, about 1 day is often enough. Fully off-grid in cloudy climates, plan for 2 to 3 days.
3. Home battery vs power station
| Portable power station | Fixed home battery system | |
|---|---|---|
| Setup | Plug and play, with a built-in inverter and solar input | Separate inverter or charger; installed by an electrician |
| Typical size | ~1 to 5 kWh, and some can be expanded | ~5 to 30+ kWh |
| Best for | Small or mobile tiny homes, backup, renters | Permanent all-electric tiny homes |
| Wiring into the house | Through an inlet or transfer switch (needs an electrician) | Hard-wired |
Compare models: Compare & filter · 1 kWh comparison · What size?
4. Safety
- Use the original charger, or a certified replacement. Avoid unbranded batteries and chargers.
- Charge on a hard surface away from exits and anything flammable, and don't leave it charging unattended overnight.
- Stop using any battery that is swollen, damaged, overheating or has been soaked, and recycle it properly.
- Store at around 40 to 70% charge somewhere cool and dry, and charge above about 0 °C.
- Don't modify a vehicle to go faster or put out more power than local limits. It can make it illegal and uninsured.
- Install batteries following the manufacturer's spacing and ventilation rules, away from sleeping areas where advised, and with proper fusing.
Tiny home rules by country (summary)
General information only, checked against official sources on 4 Nov 2026. Rules change and vary by state, province and council, so always confirm locally.
| Country / region | Key rule | Official source |
|---|---|---|
| New Zealand | A tiny house that is immovable and lived in long term is generally a building needing consent. Since 15 Jan 2026, a new single-storey standalone dwelling up to 70 m² can be built without building consent if it meets the exemption conditions, uses licensed professionals, and you get a PIM first and notify council at the end. | MBIE tiny houses · MBIE granny flat exemption |
| Australia (NSW) | A tiny house on wheels is usually a moveable dwelling/caravan. Approval exemptions are limited (for example short stays of up to 2 days in a row and 60 days a year). Otherwise expect a development application and Local Government Act s68 approval. | NSW Moveable Dwellings Regulation 2021 |
| Australia (Victoria) | A fixed "small second dwelling" up to 60 m² on a lot with an existing home often needs no planning permit, but a building permit is always required. | Victorian Building Authority |
| United States | Permanently occupied tiny houses fall under the International Residential Code (Appendix AQ, 400 sq ft or less, where adopted locally). Wheeled units built as Park Model RVs (ANSI A119.5, up to 400 sq ft) are for recreational or seasonal use, and local zoning decides where they can stay. | ICC tiny house white paper · RVIA |
| Canada | Year-round tiny homes must meet the local building code and zoning. RV-certified units (CSA Z240 RV) are not for permanent residence. | City of Calgary example |
| United Kingdom | A unit can legally be a "caravan" if movable and within 20 m × 6.8 m (3.05 m internal height). Living in one as a separate home usually needs planning permission. Ancillary use by the same household in a house's garden may not. | Caravan Sites Act 1968 s13 · GOV.UK caravan definition |
| France | A tiny house without foundations, quickly removable and used as a main home at least 8 months a year can count as a "résidence démontable", which still needs a planning declaration or permit. | Ordre des architectes (cites Code de l'urbanisme R111-51) |
| Germany | A permanently lived-in tiny house, even on wheels, is generally treated as a building that needs a permit under the state building code. | City of Munich guide (PDF) |
| Japan | A trailer house counts as a vehicle rather than a building only if it can be moved at any time and is legal on public roads, with no fixed stairs and only quick-disconnect utilities. Otherwise it needs building approval. | Hamamatsu City (Japanese) |
Electrical work: in most countries, mains wiring and grid-connected solar or batteries must be installed and certified by a licensed electrician. NZ example: WorkSafe DIY solar.
FAQ
What battery size does a tiny home need?
Multiply daily kWh by days of autonomy and divide by about 0.9 for LiFePO4. A 4 kWh/day home wanting 2 days needs about 9 kWh.
Is LiFePO4 best for tiny homes?
It is the usual choice: long cycle life, deep usable capacity and better thermal stability than other lithium types. Most can't charge below about 0 °C without heating.
Power station or home battery?
Power stations suit small, mobile or rented setups. Fixed home batteries suit permanent all-electric homes.
Where to buy
Portable power and solar kits: Power stations at ALLPOWERS (US & CA) (affiliate link).
Home batteries, inverters and solar panels: we're still waiting on approval from more brands. Until then, use a reputable local installer.
Tiny home power guides: Overview · Solar · Batteries · Power supply · EV & e-bike charging