Are solar battery storage systems dangerous? What you really need to know

The facts: how high is the fire risk really?

The answer comes from a study by the renowned RWTH Aachen University from December 2024 — one of the largest investigations ever conducted into the safety of home storage systems.

For home storage systems, LFP technology and professional installation are essential.

The system must be installed and operated according to the manufacturer’s instructions.

A modern LFP battery storage system is therefore 50 times safer than the general house fire risk — and safer than your washing machine.

Why do some batteries have a bad reputation?

Reports of burning batteries almost exclusively concern NMC batteries (nickel-manganese-cobalt) — an older technology used in early home storage systems and especially in electric cars and smartphones.

NMC batteries are chemically less stable when overheated, can catch fire due to overcharging or mechanical damage, and release oxygen during thermal runaway — which fans the flames. They are barely used in new home storage systems.

LFP batteries (lithium iron phosphate) are chemically very stable, even when overheated. Under normal conditions, the risk of thermal runaway is low. LFP is now widely used in new home storage systems.

Conclusion: if you buy a new battery storage system today, you will in all likelihood get an LFP battery — the safest technology available for home storage systems.

What is LFP and why is it so safe?

LFP stands for Lithium Iron Phosphate (LiFePO₄). This cell chemistry has decisive advantages over older lithium technologies.

Thermal stability: LFP cells only begin to decompose at over 270°C — NMC cells already from 150°C. Even in the event of a house fire, thermal runaway would not be expected.

No oxygen when overheated: Other lithium technologies can release oxygen when overheated, intensifying the fire. LFP does not do this — the fire cannot fuel itself.

Mechanical robustness: LFP cells withstand even strong mechanical loads. The famous "nail test" — a nail driven into the battery — causes no fire reaction in LFP batteries.

They thus significantly outperform NMC batteries.

Well-known manufacturers using LFP technology: BYD (HVM/HVS), Huawei (Luna), Fronius (Reserva), Fenecon (Home) — all market leaders now rely on LFP.

Where may I install a battery storage system?

Installation location is crucial for safety. In Switzerland, the following applies:

Ideal ambient temperature: 5–35°C (LFP loses a little performance in cold, but remains safe). No direct sunlight. Sufficient ventilation. Minimum distance from flammable materials according to manufacturer instructions. Do not install in escape routes.

• Basement (dry, ventilated) ✅
• Utility room ✅
• Garage (with a suitable system) ✅
• Technical room ✅
• Escape routes — prohibited ❌
• Direct sunlight — avoid ❌

What safety standards should a storage system have?

When purchasing a battery storage system, look for the following certifications:

IEC 62619 — International safety requirements for stationary lithium batteries.

VDE-AR-E 2510-50 — German standard for home storage systems — recognised in Switzerland.

CE marking — Compliance with European safety standards.

A reputable installer in Switzerland only installs systems with these certifications. Ask explicitly for them before signing.

What is the battery management system (BMS) and why is it important?

Every modern battery storage system has a battery management system (BMS) — the electronic protection layer that prevents the battery from reaching dangerous states.

The BMS monitors in real time: the temperature of each individual cell, the state of charge and depth of discharge, the current flow and voltage, and cell balancing (charging/discharging all cells evenly).

If deviations occur, the BMS immediately intervenes and interrupts the current flow. It is the most important safety component — and a quality feature that cheap no-name products often do not implement correctly.

What about Chinese batteries — are they safe?

Many Swiss homeowners ask this question, as Chinese manufacturers such as BYD and Huawei are widely represented in the Swiss market.

The honest answer: Yes, the leading Chinese manufacturers are safe — if you choose the right ones. BYD and Huawei are global leaders in LFP technology and meet all relevant international safety standards (IEC 62619, CE, UN 38.3). Their products are regularly tested by independent institutes.

The difference lies with no-name products from the low-price segment — there, quality control can be deficient. These should be avoided.

Our recommendation: Buy branded products from well-known manufacturers — whether Chinese or European matters less. More important are the certification and the guarantee.

Checklist: what to look out for when buying

Before buying a battery storage system, check these points:

• ✅ LFP technology — ask explicitly about the cell chemistry
• ✅ IEC 62619 certification — international safety standard
• ✅ CE marking — European standard
• ✅ Proven BMS — from a brand manufacturer
• ✅ Certified installer — electrical installation only by a specialist
• ✅ Correct installation location — according to manufacturer instructions and VKF guidelines
• ✅ Check fire insurance — whether your building insurance covers storage systems

What does Swiss insurance say about this?

An important practical point: is your battery storage system covered by building insurance?

In most Swiss cantons, the battery storage system is automatically covered by building insurance as a permanent part of the property — just like a heating system or an inverter.

Nevertheless, check the following: Inform your building insurance about the installation. Clarify whether damage caused by short circuits or malfunctions is covered. For rental properties: check the landlord's policy.

A reputable local installer will answer these questions — they know the practices in your canton.