Divide the capacity of the external battery by the power consumption of the central panel.
Power consumption of the central panel depends mostly on active communication modules — the average values are indicated in the table:
| Central panel | Active communication modules | Average input current |
| Hub | GSM | 42 mA |
| Ethernet | 80 mA | |
| GSM+Ethernet | 90 mA | |
| Hub Plus | GSM | 35 mA |
| Ethernet | 72 mA | |
| GSM+Ethernet | 93 mA | |
| Wi-Fi | 20 mA | |
| Wi-Fi+GSM | 42 mA | |
| Wi-Fi+Ethernet | 80 mA | |
| Wi-Fi+GSM+Ethernet | 96 mA | |
| Hub 2 | GSM | 33 mA |
| Ethernet | 80 mA | |
| GSM+Ethernet | 86 mA | |
| Hub 2 Plus | GSM | 146 mA |
| Ethernet | 200 mA | |
| GSM+Ethernet | 248 mA | |
| Wi-Fi | 98 mA | |
| Wi-Fi+GSM | 147 mA | |
| Wi-Fi+Ethernet | 213 mA | |
| Wi-Fi+GSM+Ethernet | 285 mA | |
| ReX | — | 20 mA |
For instance, when connected to a 40A·h battery, Hub 2 — with active GSM module only — will operate approximately 1200 hours (40A·h / 0.033A).
