Read maximum battery charge (mah) on Android?

Question

Is there anyway to read the battery capacity (in mah units) in Android SDK ?

Thanks

Answer 1

Yes it is possible, although there is no standard API to do so. Based on the Current Widget source code it reads a specific file for different devices.

Code below from: https://code.google.com/p/currentwidget/source/browse/trunk/CurrentWidgetLibrary/src/com/manor/currentwidget/library/CurrentReaderFactory.java

package com.manor.currentwidget.library;

import java.io.File;
import java.util.Locale;

import android.annotation.TargetApi;
import android.os.Build;

public class CurrentReaderFactory {

    static final String BUILD_MODEL = Build.MODEL.toLowerCase(Locale.ENGLISH);

    @TargetApi(4)
    static public Long getValue() {

            File f = null;

            if (CurrentReaderFactory.BUILD_MODEL.contains("nexus 7")) {
                    f = new File("/sys/class/power_supply/battery/current_now");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }                       
            }

            if (CurrentReaderFactory.BUILD_MODEL.contains("sl930")) {
                    f = new File("/sys/class/power_supply/da9052-bat/current_avg");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }                       
            }

            // Galaxy S4
            if (CurrentReaderFactory.BUILD_MODEL.contains("sgh-i337")
                            || CurrentReaderFactory.BUILD_MODEL.contains("gt-i9505")
                            || CurrentReaderFactory.BUILD_MODEL.contains("gt-i9500")
                            || CurrentReaderFactory.BUILD_MODEL.contains("sch-i545")
                            || CurrentReaderFactory.BUILD_MODEL.contains("find 5")
                            || CurrentReaderFactory.BUILD_MODEL.contains("sgh-m919")
                            || CurrentReaderFactory.BUILD_MODEL.contains("sgh-i537")) {
                    f = new File("/sys/class/power_supply/battery/current_now");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }
            }

            if (CurrentReaderFactory.BUILD_MODEL.contains("cynus")) {
                    f = new File(
                                    "/sys/devices/platform/mt6329-battery/FG_Battery_CurrentConsumption");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }
            }
            // Zopo Zp900, etc.
            if (CurrentReaderFactory.BUILD_MODEL.contains("zp900")
                            || CurrentReaderFactory.BUILD_MODEL.contains("jy-g3")
                            || CurrentReaderFactory.BUILD_MODEL.contains("zp800")
                            || CurrentReaderFactory.BUILD_MODEL.contains("zp800h")
                            || CurrentReaderFactory.BUILD_MODEL.contains("zp810")
                            || CurrentReaderFactory.BUILD_MODEL.contains("w100")
                            || CurrentReaderFactory.BUILD_MODEL.contains("zte v987")) {
                    f = new File(
                                    "/sys/class/power_supply/battery/BatteryAverageCurrent");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }
            }

            // Samsung Galaxy Tab 2
            if (CurrentReaderFactory.BUILD_MODEL.contains("gt-p31")
                            || CurrentReaderFactory.BUILD_MODEL.contains("gt-p51")) {
                    f = new File("/sys/class/power_supply/battery/current_avg");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }
            }

            // HTC One X
            if (CurrentReaderFactory.BUILD_MODEL.contains("htc one x")) {
                    f = new File("/sys/class/power_supply/battery/batt_attr_text");
                    if (f.exists()) {
                            Long value = BattAttrTextReader.getValue(f, "I_MBAT", "I_MBAT");
                            if (value != null)
                                    return value;
                    }
            }

            // wildfire S
            if (CurrentReaderFactory.BUILD_MODEL.contains("wildfire s")) {
                    f = new File("/sys/class/power_supply/battery/smem_text");
                    if (f.exists()) {
                            Long value = BattAttrTextReader.getValue(f, "eval_current",
                                            "batt_current");
                            if (value != null)
                                    return value;
                    }
            }

            // trimuph with cm7, lg ls670, galaxy s3, galaxy note 2
            if (CurrentReaderFactory.BUILD_MODEL.contains("triumph")
                            || CurrentReaderFactory.BUILD_MODEL.contains("ls670")
                            || CurrentReaderFactory.BUILD_MODEL.contains("gt-i9300")
                            || CurrentReaderFactory.BUILD_MODEL.contains("gt-n7100")
                            || CurrentReaderFactory.BUILD_MODEL.contains("sgh-i317")) {
                    f = new File("/sys/class/power_supply/battery/current_now");
                    if (f.exists()) {
                            return OneLineReader.getValue(f, false);
                    }
            }

            // htc desire hd / desire z / inspire?
            // htc evo view tablet
            if (CurrentReaderFactory.BUILD_MODEL.contains("desire hd")
                            || CurrentReaderFactory.BUILD_MODEL.contains("desire z")
                            || CurrentReaderFactory.BUILD_MODEL.contains("inspire")
                            || CurrentReaderFactory.BUILD_MODEL.contains("pg41200")) {
                    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(f,
                                    "batt_discharge_current", "batt_current");
                    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);

            // Xperia Arc
            f = new File("/sys/class/power_supply/bq27520/current_now");
            if (f.exists())
                    return OneLineReader.getValue(f, true);

            // Motorola Atrix
            f = new File(
                            "/sys/devices/platform/cpcap_battery/power_supply/usb/current_now");
            if (f.exists())
                    return OneLineReader.getValue(f, false);

            // Acer Iconia Tab A500
            f = new File("/sys/EcControl/BatCurrent");
            if (f.exists())
                    return OneLineReader.getValue(f, false);

            // charge current only, Samsung Note
            f = new File("/sys/class/power_supply/battery/batt_current_now");
            if (f.exists())
                    return OneLineReader.getValue(f, false);

            // galaxy note, galaxy s2
            f = new File("/sys/class/power_supply/battery/batt_current_adc");
            if (f.exists())
                    return OneLineReader.getValue(f, false);

            // intel
            f = new File("/sys/class/power_supply/max170xx_battery/current_now");
            if (f.exists())
                    return OneLineReader.getValue(f, true);

            // Sony Xperia U
            f = new File("/sys/class/power_supply/ab8500_fg/current_now");
            if (f.exists())
                    return OneLineReader.getValue(f, true);

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

            // Nexus 10, 4.4.
            f = new File("/sys/class/power_supply/ds2784-fuelgauge/current_now");
            if (f.exists()) {
                    return OneLineReader.getValue(f, true);
            }

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

            return null;
    }
}

Answer 2

No, sorry. You can get a charge level remaining (EXTRA_LEVEL, a value from 0 to EXTRA_SCALE), but not a raw mAH value.