Getting the battery current values for the Android Phone

Question

I am trying to collect power usage statistics for the Android G1 Phone. I am interested in knowing the values of Voltage and Current, and then able to collect statistics as reported in this PDF.

I am able to get the value of Battery voltage through registering for an intent receiver to receive the Broadcast for ACTION_BATTERY_CHANGED. But the problem is that Android does not expose the value of current through this SDK interface.

One way I tried is via sysfs interface, where I can view the battery current value from adb shell, using the following command

$cat /sys/class/power_supply/battery/batt_current
449 

But that too works only if the phone is connected via USB interface. If I disconnect the phone, I see the value of batt_current as '0'. I am not sure why the value of current reported is zero. It should be more than zero, right?

Any suggestion / pointers for getting battery current value? Also please correct me if I am wrong.

Solution 1

After several experiments and help from various other groups, I found out that there is no way of getting Battery Current value through software only (as its not supported in h/w). Only way I found was to measure current flowing through battery by means of multimeter.

Solution 2

You could just look at the source code for the Current Widget. It has hard coded path's to where certain platforms store the current values.

/*
 *  Copyright (c) 2010-2011 Ran Manor
 *  
 *  This file is part of CurrentWidget.
 *    
 *  CurrentWidget is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  CurrentWidget is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with CurrentWidget.  If not, see <http://www.gnu.org/licenses/>.
*/

package com.manor.currentwidget.library;

import java.io.File;

import android.os.Build;
import android.util.Log;

public class CurrentReaderFactory {

    static public Long getValue() {

        File f = null;      

        // htc desire hd / desire z / inspire?
        if (Build.MODEL.toLowerCase().contains("desire hd") ||
                Build.MODEL.toLowerCase().contains("desire z") ||
                Build.MODEL.toLowerCase().contains("inspire")) {

            f = new File("/sys/class/power_supply/battery/batt_current");
            if (f.exists()) {
                return OneLineReader.getValue(f, false);
            }
        }

        // nexus one cyangoenmod
        f = new File("/sys/devices/platform/ds2784-battery/getcurrent");
        if (f.exists()) {
            return OneLineReader.getValue(f, true);
        }

        // sony ericsson xperia x1
        f = new File("/sys/devices/platform/i2c-adapter/i2c-0/0-0036/power_supply/ds2746-battery/current_now");
        if (f.exists()) {
            return OneLineReader.getValue(f, false);
        }

        // xdandroid
        /*if (Build.MODEL.equalsIgnoreCase("MSM")) {*/
            f = new File("/sys/devices/platform/i2c-adapter/i2c-0/0-0036/power_supply/battery/current_now");
            if (f.exists()) {
                return OneLineReader.getValue(f, false);
            }
        /*}*/

        // droid eris
        f = new File("/sys/class/power_supply/battery/smem_text");      
        if (f.exists()) {
            Long value = SMemTextReader.getValue();
            if (value != null)
                return value;
        }

        // htc sensation / evo 3d
        f = new File("/sys/class/power_supply/battery/batt_attr_text");
        if (f.exists())
        {
            Long value = BattAttrTextReader.getValue();
            if (value != null)
                return value;
        }

        // some htc devices
        f = new File("/sys/class/power_supply/battery/batt_current");
        if (f.exists())
            return OneLineReader.getValue(f, false);

        // nexus one
        f = new File("/sys/class/power_supply/battery/current_now");
        if (f.exists())
            return OneLineReader.getValue(f, true);

        // samsung galaxy vibrant       
        f = new File("/sys/class/power_supply/battery/batt_chg_current");
        if (f.exists())
            return OneLineReader.getValue(f, false);

        // sony ericsson x10
        f = new File("/sys/class/power_supply/battery/charger_current");
        if (f.exists())
            return OneLineReader.getValue(f, false);

        // Nook Color
        f = new File("/sys/class/power_supply/max17042-0/current_now");
        if (f.exists())
            return OneLineReader.getValue(f, false);

        return null;
    }
}

Solution 3

API 21 onwards we can get the instantaneous battery current in microamperes, as an integer. Developer docs

BatteryManager mBatteryManager = (BatteryManager) getSystemService(Context.BATTERY_SERVICE);
    Long avgCurrent = null, currentNow = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
        avgCurrent = mBatteryManager.getLongProperty(BatteryManager.BATTERY_PROPERTY_CURRENT_AVERAGE);
        currentNow = mBatteryManager.getLongProperty(BatteryManager.BATTERY_PROPERTY_CURRENT_NOW);
    }
    Log.d(TAG, "BATTERY_PROPERTY_CURRENT_AVERAGE = " + avgCurrent + "mAh");
    Log.d(TAG, "BATTERY_PROPERTY_CURRENT_NOW =  " + currentNow + "mAh");

Using mBatteryManager you can get the instantaneous current reading.

Measuring Device Power and reading power consumption and the available properties on NEXUS devices. Android open source docs

Solution 4

using this function get Voltage Temperature Current in all devices.

in OnCreate to register broadcast reciever

    this.registerReceiver(this.BatteryInfo, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

and create Broadcast Receiver

    private BroadcastReceiver BatteryInfo = new BroadcastReceiver() {
    @Override
    public void onReceive(Context ctxt, Intent intent) {
        int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
        int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 100);

        boolean isPresent = intent.getBooleanExtra("present", false);

        Bundle bundle = intent.getExtras();
        String str = bundle.toString();
        Log.i("Battery Info", str);

        if (isPresent) {
            int percent = (level * 100) / scale;

            technology.setText("Technology: "+bundle.getString("technology"));
            voltage.setText("Voltage: "+bundle.getInt("voltage")+"mV");
            temp.setText("Temperature: "+bundle.getInt("temperature"));
            curent.setText("Current: "+bundle.getInt("current_avg"));
            health.setText("Health: "+getHealthString(health_));
            charging.setText("Charging: "+getStatusString(status) + "(" +getPlugTypeString(pluggedType)+")");
            battery_percentage.setText("" + percent + "%");


        } else {
            battery_percentage.setText("Battery not present!!!");
        }
    }   
};


 private String getPlugTypeString(int plugged) {
    String plugType = "Unknown";

    switch (plugged) {
    case BatteryManager.BATTERY_PLUGGED_AC:
        plugType = "AC";
        break;
    case BatteryManager.BATTERY_PLUGGED_USB:
        plugType = "USB";
        break;
    }
    return plugType;
}

private String getHealthString(int health) {
    String healthString = "Unknown";
    switch (health) {
    case BatteryManager.BATTERY_HEALTH_DEAD:
        healthString = "Dead";
        break;
    case BatteryManager.BATTERY_HEALTH_GOOD:
        healthString = "Good Condition";
        break;
    case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE:
        healthString = "Over Voltage";
        break;
    case BatteryManager.BATTERY_HEALTH_OVERHEAT:
        healthString = "Over Heat";
        break;
    case BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE:
        healthString = "Failure";
        break;
    }
    return healthString;
}
private String getStatusString(int status) {
    String statusString = "Unknown";

    switch (status) {
    case BatteryManager.BATTERY_STATUS_CHARGING:
        statusString = "Charging";
        break;
    case BatteryManager.BATTERY_STATUS_DISCHARGING:
        statusString = "Discharging";
        break;
    case BatteryManager.BATTERY_STATUS_FULL:
        statusString = "Full";
        break;
    case BatteryManager.BATTERY_STATUS_NOT_CHARGING:
        statusString = "Not Charging";
        break;
    }
    return statusString;
}

Solution 5

i found this code on Intel android developer site

public class BatteryActivity extends Activity {

    private final String TAG = "SDP_BATTERY";
    private final String DEGREE_UNICODE = "\u00B0";

    private StringBuffer textBuffer = new StringBuffer();

    // a text view to show the status of the battery
    private TextView mStatusTextView;
    // a text view to display the battery status icon
    private TextView mBatteryStatusIcon;

    /** Called when the activity is first created. */
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.battery);

        mBatteryStatusIcon = (TextView) this.findViewById(R.id.statusBattIcon);
        mStatusTextView = (TextView) this.findViewById(R.id.statusEditText);
    }

    /**
     * Once onResume is called, the activity has become visible (it is now "resumed"). Comes after onCreate
     */
    protected void onResume() {
        super.onResume();

        IntentFilter filter = new IntentFilter();

        filter.addAction(Intent.ACTION_BATTERY_CHANGED);
        Log.d(TAG, "Register battery status receiver.");
        registerReceiver(mBroadcastReceiver, filter);
    }

    /**
     * Another activity takes focus, so this activity goes to "paused" state
     */
    protected void onPause() {
        super.onPause();
        Log.d(TAG, "Unegister battery status receiver.");
        unregisterReceiver(mBroadcastReceiver);
    }

    /**
     * BroadcastReceiver is used for receiving intents (broadcasted messages) from the BatteryManager
     */
    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {

        private boolean isHealth = false;

        public void onReceive(Context context, Intent intent) {
            DecimalFormat formatter = new DecimalFormat();

            String action = intent.getAction();

            // store battery information received from BatteryManager
            if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
                Log.d(TAG, "Received battery status information.");
                int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, 0);
                int health = intent.getIntExtra(BatteryManager.EXTRA_HEALTH, 0);
                boolean present = intent.getBooleanExtra(
                        BatteryManager.EXTRA_PRESENT, false);
                int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
                int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 0);
                int icon_small = intent.getIntExtra(
                        BatteryManager.EXTRA_ICON_SMALL, 0);
                int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED,
                        0);
                int voltage = intent.getIntExtra(BatteryManager.EXTRA_VOLTAGE,
                        0);
                int temperature = intent.getIntExtra(
                        BatteryManager.EXTRA_TEMPERATURE, 0);
                String technology = intent
                        .getStringExtra(BatteryManager.EXTRA_TECHNOLOGY);

                // display the battery icon that fits the current battery status (charging/discharging)
                mBatteryStatusIcon.setCompoundDrawablesWithIntrinsicBounds(icon_small, 0, 0, 0);

                // create TextView of the remaining information , to display to screen.
                String statusString = "";

                switch (status) {
                case BatteryManager.BATTERY_STATUS_UNKNOWN:
                    statusString = "unknown";
                    break;
                case BatteryManager.BATTERY_STATUS_CHARGING:
                    statusString = "charging";
                    break;
                case BatteryManager.BATTERY_STATUS_DISCHARGING:
                    statusString = "discharging";
                    break;
                case BatteryManager.BATTERY_STATUS_NOT_CHARGING:
                    statusString = "not charging";
                    break;
                case BatteryManager.BATTERY_STATUS_FULL:
                    statusString = "full";
                    break;
                }

                String healthString = "";

                switch (health) {
                case BatteryManager.BATTERY_HEALTH_UNKNOWN:
                    healthString = "unknown";
                    break;
                case BatteryManager.BATTERY_HEALTH_GOOD:
                    healthString = "good";
                    isHealth = true;
                    break;
                case BatteryManager.BATTERY_HEALTH_OVERHEAT:
                    healthString = "overheat";
                    break;
                case BatteryManager.BATTERY_HEALTH_DEAD:
                    healthString = "dead";
                    break;
                case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE:
                    healthString = "over voltage";
                    break;
                case BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE:
                    healthString = "unspecified failure";
                    break;
                }

                String acString = "";

                switch (plugged) {
                case BatteryManager.BATTERY_PLUGGED_AC:
                    acString = "plugged AC";
                    break;
                case BatteryManager.BATTERY_PLUGGED_USB:
                    acString = "plugged USB";
                    break;
                default:
                    acString = "not plugged";
                }

                textBuffer =  new StringBuffer();
                textBuffer.append("status:" + statusString + "\n");

                formatter.applyPattern("#");
                String levelStr = formatter.format( (float)level/scale * 100 );
                textBuffer.append("level:" + levelStr + "% (out of 100)\n");
                textBuffer.append("health:" + healthString + "\n");

                textBuffer.append("present?:" + String.valueOf(present) + "\n");

                textBuffer.append("plugged?:" + acString + "\n");

                // voltage is reported in millivolts
                formatter.applyPattern(".##");
                String voltageStr = formatter.format( (float)voltage/1000 );
                textBuffer.append("voltage:" + voltageStr + "V\n");

                // temperature is reported in tenths of a degree Centigrade (from BatteryService.java)
                formatter.applyPattern(".#");
                String temperatureStr = formatter.format( (float)temperature/10 );
                textBuffer.append("temperature:" + temperatureStr
                        + "C" + DEGREE_UNICODE + "\n");

                textBuffer.append("technology:" + String.valueOf(technology)
                        + "\n");

                mStatusTextView.setText(textBuffer.toString());

                if (isHealth) {
                    Log.d(TAG, "Battery health: " + healthString);
                    Log.d(TAG, "UMSE_BATTERY_SUCCESSFULLY");
                } else {
                    Log.d(TAG, "UMSE_BATTERY_FAILED");
                }

                Log.d(TAG, textBuffer.toString());

                //finish();
            }
        }
    };

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