| Cell chemistry | Rechargeable lithium-ion | Electrochemical reactions move lithium ions between the anode and cathode while electrons flow through the external circuit. |
| Nominal cell voltage | Approximately 3.6–3.7 V | This is the average operating voltage used for capacity and energy calculations; it is not the voltage at every moment of use. |
| Fully charged cell voltage | Usually about 4.2 V | The battery-management system and charger regulate charging to prevent overvoltage. |
| Low-voltage protection | Approximately 2.5–3.0 V per cell, depending on cell design | The protection circuit disconnects the load before excessive discharge can damage the cells. The exact threshold is model-dependent. |
| Common cylindrical cell format | 18 mm diameter × 65 mm length for an 18650-type cell | Compact cylindrical cells can be arranged in series and parallel to create a larger vacuum-cleaner battery pack. |
| Typical cell capacity | About 2.0–3.5 Ah for many 18650-type cells | Higher capacity generally increases runtime, while high-current designs may prioritize power delivery and thermal performance. |
| Series connection | Voltages add; capacity in Ah remains approximately the same | A 6-cell series group has approximately 21.6–22.2 V nominal, calculated as 6 × 3.6–3.7 V. |
| Parallel connection | Capacity in Ah and available current add; voltage remains approximately the same | Two equal cells in parallel provide about twice the Ah capacity of one cell at the same nominal voltage. |
| Battery energy calculation | Energy in watt-hours ≈ nominal voltage × ampere-hours | For example, a 21.6 V, 2.5 Ah pack stores approximately 54 Wh before conversion losses and reserve limits. |
| Motor power conversion | Battery electricity is converted into mechanical airflow and suction | A motor controller regulates current to the brushless motor, which spins an impeller to create airflow and pressure difference. |
| Estimated runtime formula | Runtime in hours ≈ usable Wh ÷ average electrical power in W | A 54 Wh pack supplying an average 180 W load could theoretically run for about 0.30 hours, or 18 minutes, before practical losses and reserve capacity. |
| Power-mode effect | Higher suction requires higher electrical power | Boost mode normally shortens runtime because the motor draws more current; actual runtime also changes with floor type, airflow restriction, and attachments. |
| Battery-management system | Monitors voltage, current, temperature, and cell balance | The system helps prevent overcharging, over-discharging, excessive current, and unsafe temperature conditions. |
| Charging method | Constant-current followed by constant-voltage charging | The charger first supplies controlled current, then holds the pack at its target voltage while current gradually decreases. |
| Charging temperature | Commonly about 0–45 °C, subject to the battery design | Charging outside the permitted temperature range can reduce battery life or create a safety risk, so the control system may pause charging. |
| Factors that reduce runtime | Dirty filters, blocked airflow, dense carpet, high power mode, and battery aging | Greater resistance and higher motor demand increase energy consumption during each cleaning session. |
| Battery aging | Capacity gradually declines with cycles, time, heat, and high current | An older pack may provide shorter runtime and greater voltage sag under heavy suction, even when it still charges normally. |
| Important safety principle | Use only the specified charger and an undamaged battery pack | Lithium-ion packs should not be short-circuited, crushed, exposed to excessive heat, or disassembled without appropriate technical controls. |