Bosch power tool battery rebuilding
Bosch 18V Professional and 36V FlexiPower (GBA, ProCORE) battery rebuilding with high-current Li-ion cells and a new BMS board. 6-month warranty.
Bosch 18V Professional FlexiPower packs (GBA 18V 4.0 / 6.0 / 8.0 Ah and ProCORE 18V 4.0 / 8.0 / 12.0 Ah) are designed to be rebuilt — the housing opens, the BMS board can be replaced, and the interconnects can be spot-welded again. After 500–800 cycles, capacity drops 30–50 %, a single cell group can fall below the BMS threshold and lock out the whole pack, or the slide-on connector contacts can oxidise. We service the full Bosch professional (blue) range — GBA 18V and ProCORE 18V — as well as the Bosch 36V (BAT836, BAT838) high-voltage packs and the Bosch green DIY PBA 18V line. We also work on older Bosch 14.4 V Li-ion packs and selected NiMH/NiCd models that still see day-to-day workshop use. The process starts with a per-cell measurement of voltage, internal resistance and capacity. All cells are replaced with new high-current Li-ion cells (the specific cell model is matched to each pack’s discharge-current requirements), a fresh BMS board is fitted with proper overcharge, deep-discharge and thermal protection, and connections are spot-welded. Finally, a full charge/discharge cycle under load measures actual capacity. A rebuild costs 40–60 % less than a new original Bosch battery, and all work carries a 6-month warranty. Batteries are accepted and returned in person only.
Popular models we repair
- Bosch GBA 18V 2.0 Ah
- Bosch GBA 18V 4.0 Ah
- Bosch GBA 18V 6.0 Ah
- Bosch GBA 18V 8.0 Ah
- Bosch ProCORE 18V 4.0 Ah
- Bosch ProCORE 18V 8.0 Ah
- Bosch ProCORE 18V 12.0 Ah
- Bosch BAT836 36V
- Bosch BAT838 36V
- Bosch PBA 18V (DIY)
Common problems we fix
- Bosch GBA pack will not charge — one cell group dropped below the BMS threshold
- ProCORE 18V runtime reduced — cell wear after 500+ cycles
- Pack locked out after deep discharge or cold storage — BMS protection
- Bosch 36V BAT836/BAT838 does not respond on the charger — communication error
- Corrosion on Bosch slide-on connector contacts
- ProCORE temperature sensor fault — charging stops before completion
- Swollen cells deforming the housing — move to a rebuild immediately
- Older Bosch 14.4 V Li-ion packs worn out — still rebuildable
Detailed problem guides
Pick a symptom — we walk through the causes, what you can check yourself, and when to bring it in.
Bosch 18V Professional and ProCORE platform
The Bosch 18V Professional blue line is an open system — every 18V tool (drivers, hammer drills, angle grinders, band saws, dust extractors) uses the same pack format. Standard GBA 18V packs use 18650 cells in a 5S2P configuration (4.0 Ah) or 5S3P (6.0 Ah, 8.0 Ah). ProCORE 18V is built for high-current loads and uses newer 21700 cells: 5S1P (4.0 Ah), 5S2P (8.0 Ah) and 5S3P (12.0 Ah).
Common GBA and ProCORE issues are unbalanced cell degradation (one 5S group drops below 2.5 V and the BMS locks out charging), wear on the pack slide-connector contact blades, and BMS board failures after years of vibration and thermal stress. We start a rebuild with a full pack diagnostic — often the issue is in just one cell group or the BMS — but during the rebuild we replace every cell, because mixing cell generations creates a new imbalance immediately.
Bosch 36V and older platforms — what is still rebuildable
Bosch 36V (BAT836, BAT838) high-voltage packs power large circular saws, garden tools and heavier hammer drills. They use a 10S configuration and require precise BMS management — we only rebuild with cells matching the original specification and a quality BMS board. We also handle Bosch green DIY PBA 18V packs, although a rebuild is not always economic here (a new original PBA pack is relatively cheap).
Older Bosch 14.4 V and 12 V Li-ion packs still turn up in workshops — if the original tool is worth keeping we rebuild it with fresh 18650 cells in a 4S or 3S configuration. NiMH and NiCd Bosch rebuilds (still seen in a few specialist niches) are done on request, but we usually recommend switching to a Li-ion version if the tool supports it — higher capacity, lower weight, no memory effect.
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.