FAQ · SWITZERLAND
Frequently asked questions about sodium-ion home batteries
Updated October 24, 2026
Short answers on technology, prices, installation in Switzerland and ordering. Prices follow the current catalogue.
Sodium-ion batteries: the basics
What is a sodium-ion battery?
A sodium-ion battery stores electricity on the same principle as a lithium-ion battery, but the charge is carried by sodium ions. Sodium can be obtained from common salt, for example, and is abundant worldwide. The Heiwit HEIWIT-NA-48V210Ah battery stores 10 kWh at 48 V and contains no lithium or cobalt. More in the guide Sodium or lithium?
Is a sodium-ion battery a salt battery or a salt-water battery?
No, even though "salt battery" is often used for all sodium-based storage. There are three different technologies: sodium-ion batteries (like the Heiwit battery) with an organic electrolyte that work at room temperature; salt-water batteries with an aqueous electrolyte, very safe but bulky and rare; and high-temperature sodium-nickel-chloride batteries (ZEBRA), made for example in Ticino, which operate at over 250 °C. Swiss battery recycling also treats them as separate categories.
How does it differ from a lithium iron phosphate (LFP) battery?
LFP is the most common technology for home batteries today. Sodium-ion cells have a somewhat lower energy density (up to about 175 Wh/kg according to the IEA, against up to about 205 Wh/kg for LFP), so they are a little larger and heavier for the same capacity; in a basement this rarely matters. In return they need neither lithium nor graphite and perform much better in the cold.
Does the battery work in the cold, for example in a garage?
The HEIWIT-NA-48V210Ah discharges from −25 °C to +60 °C and charges from 0 °C to +60 °C, so below 0 °C it delivers power but does not charge. It is built for indoor use (IP20): a dry basement, plant room or dry garage is suitable, outdoor installation is not.
How safe are sodium-ion batteries?
Sodium-ion chemistry is considered more thermally stable than many lithium chemistries. In Heiwit's abuse tests (mechanical damage, short circuit) the cells did not go into thermal runaway. The risk is lower, not zero: safety depends on the whole system, i.e. cells, BMS, inverter and professional installation.
How long does the battery last?
In the laboratory endurance test the HEIWIT-NA-48V210Ah reached more than 6,500 cycles at 90% depth of discharge while keeping over 70% of its capacity. At one full cycle a day that would be about 17 years; it is a test result, not a guarantee. Heiwit gives a 10-year warranty or a returned-energy amount, whichever is reached first.
Prices, sizing and system
How much does a sodium-ion battery cost at SodiumStorage.ch?
One HEIWIT-NA-48V210Ah module with 10 kWh costs CHF 3’896.– including 8.1% Swiss VAT, about CHF 390.– per kWh of nominal capacity or CHF 433.– per usable kWh (9 kWh at 90% depth of discharge). Three modules with 30 kWh cost CHF 11’688.–. A hybrid inverter (VIRGO from CHF 1’055.–, LYBRA from CHF 1’988.–), accessories, shipping and installation come on top. For comparison: according to Swissolar, an installed 15 kWh home battery cost about CHF 8’850.– on average in Switzerland in 2025.
How much storage do I need?
Swissolar recommends two rules of thumb and taking the smaller value: one thousandth of the annual PV production or one thousandth of the annual consumption, with at most about 1.5 kWh of usable capacity per kW of PV power. A house with a heat pump, 9,000 kWh consumption and 12 kWp of PV thus needs about 9 kWh: one 10 kWh module (9 kWh usable). Worked examples in the guide Battery sizing.
Which inverters work with the battery?
We sell the battery with Heiwit hybrid inverters VIRGO (single-phase, 3 to 6 kW) and LYBRA (three-phase, 6 to 12 kW) for 48 V batteries; the manufacturer documentation covers these combinations. If you plan to use another inverter, ask us before ordering.
Single-phase or three-phase: VIRGO or LYBRA?
The Swiss connection rules WV-CH 2025 allow generating and storage units of at most 3.7 kVA on one phase; larger units are connected symmetrically on three phases. The single-phase VIRGO 3K therefore fits without restriction, the VIRGO 4.6K and 6K only with power limited to 3.7 kVA or an exception from the grid operator. For most detached houses, which have a three-phase connection (3 × 400 V), the three-phase LYBRA (6 to 12 kW) is the right choice.
Can I add the battery to an existing PV system?
In many cases yes, with a VIRGO or LYBRA hybrid inverter to which the battery and the PV modules are connected. Whether the existing inverter is replaced or kept is decided by the installer after checking your system (strings, connection capacity, meter board).
Do I get backup power during a blackout?
With a backup panel (single-phase or three-phase) the system switches automatically to the backup output (EPS) when the grid fails. Battery and PV then keep supplying the circuits connected to it. The installer decides which loads go on the backup output.
Installation and rules in Switzerland
Can I install the battery myself?
No. Under the Low-Voltage Installation Ordinance (NIV), only holders of an installation permit may carry out electrical installations; the restricted permit for photovoltaics only covers the system up to the inverter output. The electrician files the installation notice with the grid operator and completes the work with a safety certificate (SiNa) and test report. The manufacturer's warranty also requires a professional installation.
What applies to the grid connection?
Your distribution system operator must approve the connection. Its technical connection conditions apply, based on the WV-CH rules and the VSE industry recommendation NA/EEA-NE7-CH with the Swiss country setting. The Italian CEI 0-21 certificates of the Heiwit devices do not replace Swiss requirements: have the suitability checked before ordering; the datasheets are on the product pages.
Are there subsidies for home batteries?
There is no federal subsidy for batteries in residential buildings; Pronovo's one-off remuneration covers the PV system, not the battery. Some cantons support storage, such as Schaffhausen and Thurgau since January 2026 with a one-off CHF 1’000.– for batteries of 10 kWh or more (at most a quarter of the investment), plus Neuchâtel. Municipalities pay grants too, for example the City of Zurich since August 2026: CHF 1’000.– plus CHF 100.– per kWh (with a PV system and energy management). All programmes by postcode are listed on energiefranken.ch.
What has changed for home batteries since 2026?
Since 1 January 2026, storage systems with end consumption can claim a refund of the grid usage fee for electricity taken from the grid, stored and fed back (with a suitable metering system). Local electricity communities (LEG) are also possible, and without an agreement with the grid operator the feed-in remuneration follows the quarterly average market price. This makes storing solar power more valuable. More in the guide Home batteries in Switzerland.
How is the battery disposed of at the end of its life?
In Switzerland batteries must not go in the household waste. INOBAT organises take-back and recycling on behalf of the Federal Office for the Environment (FOEN), financed by the advance recycling fee that manufacturers and importers pay for every battery placed on the market. At the end of its life you hand the battery in at a collection point; on request we tell you the take-back options.
Ordering, delivery and warranty
How do I order and pay?
Add the items to the cart and send the order. We check availability and delivery date and send you a pro-forma invoice with the bank details; payment is by bank transfer within 10 days. There is no online payment, and nothing is paid before our confirmation.
Do you deliver throughout Switzerland? What does shipping cost?
We deliver to addresses throughout Switzerland, not abroad. Batteries are dangerous goods (ADR class 9) and are delivered by a freight carrier, at ground level to the kerb. The shipping costs are shown on the pro-forma invoice.
Can I cancel or return an order?
Swiss law has no general right of withdrawal for online purchases. Returns are only possible with our prior written consent, for new, uninstalled goods in their original packaging and against a 20% handling fee. Details are in the terms of sale.
Who is behind SodiumStorage.ch and who gives the warranty?
SodiumStorage.ch is the online shop of JAN Suisse SA in Lugano, independent importer of Heiwit products for Switzerland. The manufacturer is Heiwit S.p.A. in Varese (Italy). Heiwit's warranty conditions apply; we forward warranty claims to the manufacturer and coordinate repair or replacement. More under About us.
How do I monitor the battery and inverter?
With the Heiwit Solar app for Android and iOS and with AI-Care Smart Energy Manager. The inverters come with an antenna and remote monitoring software.
Your question is not here? Write to us using the contact form