Garden tool battery repair in Riga — SATER

Garden tool battery rebuilding begins with detailed diagnostics — we measure the voltage and internal resistance of every cell group, check BMS board communication with the charger and analyse the symptoms described by the customer. A typical Husqvarna BLi200 battery contains 10 series groups (10s configuration) with a nominal voltage of 36V, while a Makita 18V LXT is a 5s configuration with 5 series groups. Each group may have 1–3 parallel cells depending on pack capacity — for example, a Ryobi ONE+ 4.0Ah is 5s2p (10 cells) and the 6.0Ah is 5s3p (15 cells).

After diagnostics the customer receives a report showing the condition of every group along with a recommendation. During a full rebuild we replace every cell with new SONY, Samsung 30Q/40T or MOLICEL P42A — chosen according to the required current profile. Garden tools often demand cells with high pulse current (20–30A), so we select cells with low internal resistance. BMS reset is performed with a dedicated diagnostic tool — we connect to the BMS board test points, clear error codes, calibrate the capacity counter and verify the balancing function. Certain manufacturers (e.g. Husqvarna and Stihl) require a proprietary communication protocol for BMS reset, which we have mastered over years of experience.

In Latvia the gardening season typically runs from April to October, which means garden tool batteries spend five to six months in storage. This extended idle period is the main reason garden tool batteries degrade faster than comparable batteries that are used regularly. Lithium-ion cell self-discharge rate is roughly 2–3% per month at room temperature, and at low temperatures (below 0°C) there is an additional risk of lithium plating on the anode, which irreversibly reduces capacity.

The ideal storage strategy is as follows: before putting the battery away, charge it to 40–60%, place it in a dry space at 10–20°C and top it up once every two to three months. Never store a battery fully discharged — if cell voltage drops below 2.5V the BMS will lock out, and the battery often can no longer be charged with the standard charger. Also avoid storing at 100% charge — this accelerates cathode material degradation. If your battery has already suffered from winter storage — BMS locked, charger does not recognise the battery, or runtime has dropped sharply — visit our service centre at Silmaču iela 6. We will diagnose the battery and, if needed, perform a BMS reset or full cell replacement with a 6-month warranty.