How to calculate the run time for an external battery connected via 6V PSU (type A)


The run time of an external battery connected to Ajax hubs or range extenders via 6V PSU (type A) depends on the following parameters:

  • Number of active communication channels: Ethernet, Wi-Fi, cellular network.
  • Stability of connection via communication channels.
  • Battery voltage and capacity.
  • Battery self-discharge current.
  • Ambient temperature (depends on the type and model of a battery).
  • Hub–server polling interval.

Also, the battery life is slightly affected by the number of devices paired with the hub or range extender and Jeweller settings.

All these factors may affect the battery run time, making the calculations approximate.

External battery life calculator

Estimate run time for external batteries connected to Ajax hubs or range extenders via 6V PSU or 12-24V PSU


Do not connect batteries with an output voltage of 12 V⎓ or higher to hubs or range extenders via 6V PSU (type A). Such batteries can damage the device.

Note that 6V PSU (type A) is incompatible with Hub Hybrid (2G) and Hub Hybrid (4G). Check this chart to find out which PSU is compatible with your hub.

Battery operation basics and recommendations

A battery is a chemical power cell affected by the ambient temperature. The lower the temperature, the slower the chemical processes, and the lower the battery capacity. If possible, install batteries in locations with the ambient temperature above 0 °C.

Actual battery specifications may differ from those stated by the manufacturer. Batteries from the same batch may have different capacities and output voltages or even may be defective.

Use only qualitative batteries from known manufacturers. These batteries are more expensive and have longer life. If possible, connect batteries only from the recommended list.

We recommend using zinc-air alkaline batteries for extended battery life. Before connecting this battery type, make sure to remove the stickers from it or open the air shutoff valves. If possible, leave the battery with access to the air for 2 hours. Air is needed to start a chemical reaction inside the battery and ensure its proper operation.

Hub and range extender power consumption optimization

When using external batteries, do not activate settings that unnecessarily utilize the hub or range extender radio module. In particular, such settings include the Always Active mode and the reduction of the detector ping interval.

Disable unused communication channels to ensure longer hub or range extender battery life. For example, disable Wi-Fi in the hub settings or Ethernet in the range extender settings if you are not going to connect this communication channel.

It’s not recommended to install the hub in places with unstable cellular communication. The unstable connection with the server most affects the time of hub operation from the external battery.

Keep in mind that the hub or range extender stops operating on the external battery connected via 6V PSU (type A) if the battery voltage drops below 3.5 V⎓. Even if the external battery still has the capacity, the hub or range extender will not be able to operate on it.

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