Robot vacuum battery rebuild in Riga — SATER

The lithium-ion cells inside robot vacuum battery packs gradually degrade with every charge and discharge cycle. After approximately 500–800 full cycles — roughly 1.5 to 3 years of daily use — the cell chemistry changes irreversibly. The cathode material loses its ability to hold lithium ions efficiently, and battery capacity begins to drop rapidly.

Robots that originally ran for 90–120 minutes on a single charge now die after just 15–25 minutes. Moreover, degraded cells often lose capacity unevenly — one cell group may be nearly healthy while another is completely worn out. This creates a voltage imbalance that the BMS board interprets as a fault and may lock out the entire pack as a safety precaution. An even more dangerous condition occurs when degraded cells start generating gas and physically swell — this can deform the battery housing and create a safety hazard. A robot running on a swollen battery should be shut down immediately. All of these scenarios are resolved by a complete cell replacement — something we have been doing at SATER service centre in Riga for over 30 years.

The SATER battery rebuild process begins with measuring each cell's voltage individually, which lets us pinpoint exactly how many cells have degraded and whether the BMS board is functioning correctly. After diagnostics we fully disassemble the battery pack — detach the cells from their spot-weld points, remove the old BMS board and prepare the housing for new components.

We then install new SONY, SAMSUNG, MOLICEL or PANASONIC lithium-ion cells, following the original series-parallel configuration (for example, 4S1P for iRobot Roomba 14.4 V or 4S2P for Roborock 14.4 V 5200 mAh packs). Every cell is tested before installation to ensure uniform capacity and internal resistance across the entire pack. After spot-welding new interconnects we fit a fresh BMS board calibrated to the specific configuration. Finally, we run a full charge-discharge test, measuring actual capacity and verifying that the BMS correctly manages all protection parameters — overcharge, deep discharge, short circuit and thermal protection. The result is a battery that performs as well as or better than the original, backed by a 6-month warranty.