A LiFePO4 home battery can usually discharge in freezing weather, but charging it below 0 °C is a different question: charging below freezing can plate metallic lithium onto the anode, which permanently reduces capacity and, in the worst case, creates a safety risk. For an installer planning a winter commissioning, the decision is not whether the chemistry "works" in the cold — it is where the pack is sited and whether its battery management system is allowed to charge at the temperatures that site actually reaches.
Why the 0 °C line matters
Below roughly 0 °C, lithium ions arriving at the anode during charging cannot move into the graphite fast enough, so some deposit as metallic lithium on the surface instead of intercalating. That is lithium plating. It is a charging problem, it accumulates, and each cold charge can shave usable capacity while slowly raising the risk of an internal short. The mechanism and its effect on cell aging are documented in the peer-reviewed literature — see the low-temperature aging study in the Journal of Power Sources (ScienceDirect) and the sub-zero temperature cycling safety study from the Electrochemical Innovation Lab (UCL Discovery, open access).
The practical takeaway: it is the temperature of the cells, not the air temperature on the day of your site visit, that decides whether charging is safe.
Charging and discharging do not share the same cold limit
The two directions behave differently in the cold, and conflating them is the most common winter mistake:
| Behaviour | Above the charge cut-off | At or below it |
|---|---|---|
| Charging | Permitted within the rated current | Blocked or restricted by the BMS to avoid plating |
| Discharging | Normal | Often still allowed, at reduced usable capacity and power |
| Usable energy | Close to nameplate | Lower than nameplate while the pack is cold |
| Risk if pushed | Low | Plating and permanent capacity loss (charging in the cold) |
As a general industry reference, most LiFePO4 datasheets state a minimum charging temperature at or near 0 °C, while the discharge window extends well below that — see RELiON's cold-temperature guidance as one example of how that line is stated. A battery that is simply sitting cold, not being charged, is not the problem.
What "IP65" does not tell you about temperature
An IP rating describes protection against dust and water — IP65 means dust-tight and resistant to water jets. It says nothing about the temperature window the cells or the BMS are rated for. An outdoor-rated pack mounted on a north-facing wall and an indoor pack in an unheated garage can both fall below the charge cut-off on the same February night, even though only one of them is "outdoor". Treat the IP rating and the temperature window as two separate questions, and ask for both. Our guide to IP65 outdoor batteries covers the enclosure side of that decision.
How a BMS protects a pack that is too cold to charge
A well-designed pack does not rely on the installer to remember the temperature — the battery management system reads cell temperature and refuses to charge when it is unsafe. What to confirm in the documentation:
- Low-temperature charge cut-off — the threshold at which the BMS blocks charge current, and whether it is configurable.
- Temperature sensing — where the sensors sit, so the reading reflects cell temperature rather than ambient air.
- Charge resume behaviour — whether charging re-enables automatically once cells warm, or needs a setting.
- Discharge protection — the low-temperature discharge limit, which is separate from the charge limit.
- Heating (if any) — some cold-climate designs include a heater or a low-temperature charge-window; if it is present, it should be stated in the spec, and if it is absent, the siting plan has to carry the load.
Do not assume a heater is present. If the spec sheet does not state one, plan the site as if it does not exist.
A winter planning checklist for installers
| Check | Why it matters in winter |
|---|---|
| Measure the ambient at the install position, in the coldest month | Air temperature at the wall, not the weather forecast, sets the risk |
| Read the charge cut-off from the datasheet and settings | It is SKU-specific and must be a known number, not an assumption |
| Decide whether the space can drop below the cut-off | If it can, the pack needs a warmer position or a charge strategy |
| Confirm ventilation and clearances per the manual | Insulating a pack to keep it warm can conflict with the manual's airflow rules |
| Check inverter pairing before relying on any figure | Cold performance still depends on the verified pairing — see our inverter compatibility guidance |
| Record the commissioning conditions | A warranty claim turns on what was documented — see warranty terms explained |
Where to site a home battery when the space gets cold
Siting does most of the work in a cold climate:
- Prefer a space that stays within the pack's charge window — a utility room or heated garage over an unheated outbuilding or a fully exposed outdoor wall.
- If the only option is an unheated space, check whether it stays above the charge cut-off in the coldest week, not the average week.
- Keep the manual's clearances even when you are trying to shelter the pack — do not box it in.
- Plan the electrical and mounting work as usual; our installation and site-prep guide covers the general sequence.
The Storage Wall series is a wall-mounted LiFePO4 line from 2.56 to 14.34 kWh, with an IP65 outdoor variant (SEN-051200 IP65) for sheltered outdoor installs where the local code and site conditions allow it. Enclosure protection and the temperature window are separate — ask for both figures for the exact SKU.
The cycle-life number assumes a temperature
A published cycle rating such as 6,000 cycles at 80% depth of discharge is quoted at a stated temperature — commonly 25 °C. That condition is part of the number, so a pack that spends a heating season cold will not necessarily follow the same curve. This is not a reason to avoid storage; it is a reason to publish, and to read, the test condition alongside the figure. Our explainer on what 6000 cycles actually means walks through how to translate the condition into years of service, and the datasheet-reading guide covers which conditions to look for.
Questions to send a supplier before winter commissioning
- What are the charge and discharge temperature windows for this exact SKU?
- At what cell temperature does the BMS block charging, and is it configurable?
- Does the pack include low-temperature charge protection, and is any heating specified?
- What ambient conditions void the warranty, and what must be recorded at commissioning?
- What is the verified inverter compatibility list for this SKU?
What we publish, and what to ask us
We publish specifications with their test conditions rather than a headline alone, and we keep certification and performance claims inside what we can evidence for the exact SKU. Where a figure is SKU-specific — the charge and discharge temperature windows are a good example — we return it in writing rather than approximate it in a brochure. Send us the SKU, the destination market and the site conditions, and we will return the datasheet with the temperature windows and the low-temperature charge behaviour marked, plus a note on what to record at commissioning.
Tell us about the project, or browse the full storage range and the Storage Wall series.