Battery overheating — diagnostics and safe repair in Riga
If your device's battery becomes unusually hot during charging or use — the surface is too hot to hold, you notice a chemical smell, or the battery has started to deform — stop using the device immediately and disconnect the charger. Battery overheating is a serious safety hazard that can lead to thermal runaway, fire, or explosion.
At the SATER service centre on Silmacu iela 6, we have been diagnosing and repairing overheating batteries for over 30 years, following strict safety protocols. Battery overheating is not a problem that can be solved at home — it requires professional diagnostics with a thermal camera and laboratory equipment. Our technicians first assess the battery's safety status: we check for cell deformation, measure each cell's voltage and internal resistance to identify potentially dangerous cells with internal short circuits. If the battery is safe for further diagnostics, we verify BMS temperature sensor calibration, charger output voltage, and cell balance status. An overheating battery often points to one or more cells with elevated internal resistance generating excessive heat. Such cells must be replaced immediately. We use premium SONY, MOLICEL, SAMSUNG, LG, and PANASONIC cells with the lowest possible internal resistance, ensuring minimal heat generation during normal operation. After the repair we run an extended load test with temperature monitoring to confirm the battery operates within a safe temperature range. All battery work comes with a 6-month warranty. If your battery is overheating — stop using it immediately and bring the device to Silmacu iela 6.
Likely causes
- Internal cell short circuit — dangerous, stop using immediately — An internal cell short circuit is the most dangerous type of battery damage. Inside the cell, the separator between the anode and cathode can degrade or sustain mechanical damage, creating direct contact between the electrodes. This generates uncontrolled heat that can trigger thermal runaway — a chain reaction where heat accelerates chemical reactions that in turn generate even more heat. If the battery is very hot and/or deforming, immediately place the device on a non-combustible surface and disconnect the charger.
- BMS temperature sensor failure — does not react to overheating — The BMS temperature sensor (NTC thermistor) is designed to shut down the battery when it reaches a dangerous temperature (typically 60-70 C). If this sensor is faulty or disconnected, the BMS receives no accurate temperature data and cannot activate protection. The battery continues operating even when its temperature is already in the danger zone. We replace the faulty sensor and calibrate the BMS temperature thresholds.
- Charger voltage too high — charging with incorrect parameters — If the charger is faulty or an incompatible charger is used, the output voltage can exceed the battery's rated level. For example, instead of 4.35 V, the charger delivers 4.5 V per cell — this difference causes overcharging, which generates excessive heat and can irreversibly damage the cell's internal structure. We measure charger output voltage and current with an oscilloscope throughout the entire charging cycle.
- Cell imbalance — one cell overworked — In a battery pack, cells are connected in series and each group should charge to the same voltage. If one cell has degraded and its capacity is lower, it reaches full charge before the others, but charging continues because the BMS looks at total voltage. As a result, the weak cell is overcharged and overheats. The BMS balancing circuit may not be fast enough to compensate for a large imbalance.
- Poor ventilation in device — heat cannot dissipate — Some batteries are installed in enclosed compartments without adequate ventilation. If the device's ventilation openings are clogged with dust or the compartment is inherently poorly ventilated, normal operating heat cannot dissipate and battery temperature gradually rises. Over time this accelerates cell degradation and increases the risk of overheating.
What you can check yourself
- IMMEDIATELY stop using the device and disconnect the charger — an overheating battery is a safety hazard.
- Place the device on a non-combustible surface (ceramic, metal, concrete) away from flammable materials and do not leave it unattended.
- Check that you are using the original charger or one with the correct specifications — an incompatible charger is a common cause of overheating.
- Check whether the device ventilation openings are clogged with dust — clean them with a soft brush or compressed air.
- Do not continue using the device if the battery is visibly deformed or swollen — this indicates internal cell damage.
When to bring it in
An overheating battery requires immediate professional diagnostics. Bring the device to the SATER service centre at Silmacu iela 6 as soon as possible, especially if the battery is deformed, emits a chemical smell, or its temperature exceeds 50 C. We will diagnose with a thermal camera and laboratory equipment to determine the cause and assess safety. We agree on a cost estimate before starting work, and all battery repairs come with a 6-month warranty. Call +371 67377002.
Battery replacement warranty: 6 months.
Affected brands
Frequently asked questions
Why customers choose SATER
- Custom-built battery assemblies. We design and assemble packs for the exact device — no 'close enough' substitutes.
- Sony, Samsung, LG, Panasonic, Molicel cells. Only top-tier cells — each one capacity-tested before assembly.
- Batteries for robots, power tools, laptops. We build packs for any device that runs on lithium batteries.
- 30+ years of experience. The service centre has been operating since 1993.
- We serve all of Latvia. Our service centre is in Riga and we accept devices from anywhere in the country.