Battery Sleep Management

This feature is for trackers on boards without an AXP/PMU chip (for example the Heltec Wireless Tracker). These boards have no hardware battery protection, so the firmware takes care of low-battery sleep on its own. It works well in practice and lets you just leave the tracker running — in a car, a backpack, on a bike — without ever having to touch or restart it by hand.

To learn the difference between hardware power-off (AXP) and software deep sleep, see Power Off Modes.

What it does

When the battery gets low, the tracker reports once that it is going to sleep, and then sleeps quietly:

• It does not transmit, does not turn on the radio or WiFi, and does not waste power.
• It does not clutter the APRS network with repeated low-battery messages.
• Every now and then it wakes for a moment just to check the voltage.
• When you connect charging, it notices the voltage rising and brings itself back to full operation on its own once it is safe.

The tracker quietly learns its own battery over time, so it can tell the difference between a brief voltage dip (which happens normally while transmitting) and a battery that is really running out. This avoids the annoying loops some devices fall into, where they keep resetting or repeatedly sleeping and waking on a weak cell.

Why it’s nice to use

The whole point is that you don’t have to think about it. The tracker manages its own battery sensibly:

• No manual restarts — it returns on its own after charging.
• No constant resets on a low battery.
• No spam on the APRS network.

You can simply install it and forget about it until it’s time to charge.