Power tool battery rebuild
Battery rebuilds for Makita, DeWalt, Bosch, Milwaukee, Hilti and Festool packs with high-drain Li-ion cells and a fresh BMS board.
A professional impact driver or angle grinder draws 30–50 A at peak — a load that wears a power tool battery out in 500–800 cycles. Typical failure modes: one cell group drops below the BMS threshold and the pack locks out, the battery refuses to charge after a cold pull, the charge contacts pick up oxide, or the T-shape or slide-fit connector loses its contact blades. We service every common professional platform: Makita 18V LXT and 40V Max XGT (BL1850B, BL1860B), DeWalt 20V Max and 60V FlexVolt (DCB205, DCB206), Bosch 18V Professional FlexiPower (GBA 18V), Metabo 18V LiHD, Milwaukee M12 and M18 RedLithium, Hilti 22V (B22), Festool 18V (BP 18 Li), Hitachi/HiKOKI and Ryobi ONE+. We also rebuild older NiCd and NiMH packs that still earn their keep in professional tools. The rebuild starts with individual cell diagnostics — voltage, internal resistance and actual capacity. We then strip the pack, replace every cell with new high-drain Li-ion cells (mixing old and new triggers immediate imbalance), fit a fresh BMS board and spot-weld the interconnects. A full charge-discharge test under real load closes the job, with measured capacity and peak current logged. The result often beats the original factory rating, and a rebuild costs significantly less than a new OEM pack. All battery work carries a 6-month warranty. In-person drop-off only — we do not accept postal shipments.
Popular models we repair
- Makita 18V LXT (BL1850B, BL1860B)
- Makita 40V Max XGT
- DeWalt 20V MAX (DCB205, DCB206)
- DeWalt 60V FlexVolt
- Bosch 18V Professional (GBA 18V)
- Metabo 18V LiHD (625369)
- Milwaukee M18 RedLithium (48-11-1850)
- Milwaukee M12 RedLithium
- Hilti 22V (B22)
- Festool 18V (BP 18 Li)
- Hitachi/HiKOKI 18V
- Ryobi ONE+ 18V
Common problems we fix
- One cell group dead — tool dies under load
- BMS lockout after a cold pull — battery will not charge at all
- Cells have lost capacity after 500+ cycles — run time has dropped
- Battery overheats during heavy use — unstable cell
- Charge indicator reads inaccurately — BMS fault
- Corrosion on charge contacts — weak connection
- Worn contact blades on the T-shape or slide-fit connector
- Battery does not register in the charger — communication error
- Swollen cells causing the case to crack — dangerous
Detailed problem guides
Pick a symptom — we walk through the causes, what you can check yourself, and when to bring it in.
Why power tool batteries fail and when to rebuild vs replace
Power tool batteries operate under extremely harsh conditions — peak discharge currents of 30–50 A, vibration, dust and temperature swings. These factors combine to cause accelerated cell degradation. After 500–800 full cycles — which for a professional user may be as little as 1–2 years — battery capacity drops by 30–50% and the tool can no longer deliver full power.
The most common failure mode is one cell group dying while the rest are still relatively healthy. In this scenario the BMS detects a voltage imbalance and locks out the entire pack — the tool simply will not work even though most of the cells are still functional. Another common pattern is a cold-weather lockout: a user pulls the pack from a cold garage, the BMS sees a sagging cell and shuts the pack down until a workshop reset. Corrosion on the charge contacts and worn contact blades on the T-shape or slide-fit connector show up just as often. In all of these cases a rebuild is far more cost-effective than buying a new OEM battery — especially for professional brands where a new battery can cost EUR 100–200 or more.
The rebuild process: diagnostics, cell replacement, BMS, load test
In our rebuild process we use only high-drain Li-ion cells specifically designed for power tool loads (45 A continuous discharge and above). The exact cell choice is matched to the pack form factor, platform voltage and BMS requirements — see the FAQ for the cells we run.
The rebuild starts with individual cell diagnostics — we measure voltage, internal resistance and capacity to pinpoint the exact degree of degradation. We then fully disassemble the pack, replace all cells (even those that still work — mixing cell generations creates imbalance), fit a fresh BMS board and spot-weld the interconnects. Finally, we run a full charge-discharge test under real load, measuring actual capacity and peak current. This meticulous process ensures the rebuilt battery operates safely and reliably under professional working conditions. Battery work carries a 6-month warranty.
Pricing & warranty
Battery replacement warranty: 6 months.
If the repair cost changes during the process, the technician will call to agree on the new price. No work is done without your consent.
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. Electronics service centre in Riga — we accept devices from anywhere in the country.