Is there a way to suppress the Low Battery warning on Android devices or dismiss the alert pop-up?

Question

We are developing an Android application that will be running on devices fitted with large batteries, so as to provide a longer running time between charges.

The problem is that the operating system does not read the power levels of the battery correctly and displays the low battery alert when there is a lot of charge left.

We have used a device for an extended period of time on a single battery charge and have been presented with the low battery alert approximately every 4 hours.

Is there any way of preventing this alert from appearing without having to root the device? Should it be possible to intercept the broadcast of the battery status and prevent the system from responding to it? Or is there anything that we can do to dismiss the battery warning as soon as it is displayed?

Our research so far has turned up nothing, as we suspect that this is not possible for security reasons. Hopefully one of you Android experts can confirm/deny our suspicions.

Answer 1

Let's dig into android source code:

---

BatteryService

There is a BatteryService which is responsible for detecting when battery is low and if this happens it sends appropriate broadcast. The exact place that detects whether battery is low can be found here.

/* The ACTION_BATTERY_LOW broadcast is sent in these situations:
 * - is just un-plugged (previously was plugged) and battery level is
 *   less than or equal to WARNING, or
 * - is not plugged and battery level falls to WARNING boundary
 *   (becomes <= mLowBatteryWarningLevel).
 */
final boolean sendBatteryLow = !plugged
    && mBatteryStatus != BatteryManager.BATTERY_STATUS_UNKNOWN
    && mBatteryLevel <= mLowBatteryWarningLevel
    && (oldPlugged || mLastBatteryLevel > mLowBatteryWarningLevel);

...
if (sendBatteryLow) {
        mSentLowBatteryBroadcast = true;
        statusIntent.setAction(Intent.ACTION_BATTERY_LOW);
        mContext.sendBroadcast(statusIntent);
}

You won't be able to modify this behavior without rebuilding the Android OS. You could probably change mLowBatteryWarningLevel value because its taken from com.android.internal.R.integer.config_lowBatteryWarningLevel resource. But this requires root and will invalidate the signature of package where this resources is located.

---

StatusBarPolicy

So we now know that BatteryService sends broadcast when batter gets low. But its clear from the source code that it does not show the warning. So next step was to find who actually shows that "low battery" warning. The class responsible for this is StatusBarPolicy. Its not documented. Two pieces of code that can be interesting to you are onBatteryLow() and showLowBatteryWarning() functions.

But these two functions have no reasonable influence points from outter world. So no hacks will help you here also.

---

So it looks like this will be impossible without root. And even if you had root this would be challenging as you need to modify either resources or code (and then re-sign them).