I have dual boot system-Linux Mint 18.1 with windows 10. I have been working in LM O.S for past few days with windows 10 shutdown properly. It seems to me that battery is draining faster than it used to in windows 10 mode.
Kindly suggest some remedy.

I installed TLP whose output is
legend@legend-HP-ProBook-6470b ~ $ sudo tlp stat
--- TLP 0.8 --------------------------------------------

+++ Configured Settings: /etc/default/tlp
TLP_ENABLE=1
TLP_DEFAULT_MODE=AC
DISK_IDLE_SECS_ON_AC=0
DISK_IDLE_SECS_ON_BAT=2
MAX_LOST_WORK_SECS_ON_AC=15
MAX_LOST_WORK_SECS_ON_BAT=60
SCHED_POWERSAVE_ON_AC=0
SCHED_POWERSAVE_ON_BAT=1
NMI_WATCHDOG=0
ENERGY_PERF_POLICY_ON_AC=performance
ENERGY_PERF_POLICY_ON_BAT=powersave
DISK_DEVICES="sda sdb"
DISK_APM_LEVEL_ON_AC="254 254"
DISK_APM_LEVEL_ON_BAT="128 128"
SATA_LINKPWR_ON_AC=max_performance
SATA_LINKPWR_ON_BAT=min_power
PCIE_ASPM_ON_AC=performance
PCIE_ASPM_ON_BAT=powersave
RADEON_POWER_PROFILE_ON_AC=high
RADEON_POWER_PROFILE_ON_BAT=low
RADEON_DPM_STATE_ON_AC=performance
RADEON_DPM_STATE_ON_BAT=battery
RADEON_DPM_PERF_LEVEL_ON_AC=auto
RADEON_DPM_PERF_LEVEL_ON_BAT=auto
WIFI_PWR_ON_AC=1
WIFI_PWR_ON_BAT=5
WOL_DISABLE=Y
SOUND_POWER_SAVE_ON_AC=0
SOUND_POWER_SAVE_ON_BAT=1
SOUND_POWER_SAVE_CONTROLLER=Y
BAY_POWEROFF_ON_BAT=0
BAY_DEVICE="sr0"
RUNTIME_PM_ON_AC=on
RUNTIME_PM_ON_BAT=auto
RUNTIME_PM_ALL=1
RUNTIME_PM_DRIVER_BLACKLIST="radeon nouveau"
USB_AUTOSUSPEND=1
USB_BLACKLIST_WWAN=1
RESTORE_DEVICE_STATE_ON_STARTUP=0

+++ System Info
System = Hewlett-Packard A1019DD200 HP ProBook 6470b
BIOS = 68ICF Ver. F.42
Release = Linux Mint 18.1 Serena
Kernel = 4.4.0-112-generic #135-Ubuntu SMP Fri Jan 19 11:48:36 UTC 2018 x86_64
/proc/cmdline = BOOT_IMAGE=/boot/vmlinuz-4.4.0-112-generic root=UUID=39f38d66-53cb-49ea-aa51-f03c7cc2c0a4 ro quiet splash
Init system = systemd

+++ System Status
TLP power save = enabled
power source = battery

+++ Processor
CPU Model = Intel(R) Core(TM) i7-3540M CPU @ 3.00GHz

/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver = intel_pstate
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor = powersave
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq = 1200000 [kHz]
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq = 3700000 [kHz]

/sys/devices/system/cpu/cpu1/cpufreq/scaling_driver = intel_pstate
/sys/devices/system/cpu/cpu1/cpufreq/scaling_governor = powersave
/sys/devices/system/cpu/cpu1/cpufreq/scaling_min_freq = 1200000 [kHz]
/sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq = 3700000 [kHz]

/sys/devices/system/cpu/cpu2/cpufreq/scaling_driver = intel_pstate
/sys/devices/system/cpu/cpu2/cpufreq/scaling_governor = powersave
/sys/devices/system/cpu/cpu2/cpufreq/scaling_min_freq = 1200000 [kHz]
/sys/devices/system/cpu/cpu2/cpufreq/scaling_max_freq = 3700000 [kHz]

/sys/devices/system/cpu/cpu3/cpufreq/scaling_driver = intel_pstate
/sys/devices/system/cpu/cpu3/cpufreq/scaling_governor = powersave
/sys/devices/system/cpu/cpu3/cpufreq/scaling_min_freq = 1200000 [kHz]
/sys/devices/system/cpu/cpu3/cpufreq/scaling_max_freq = 3700000 [kHz]

/sys/devices/system/cpu/intel_pstate/min_perf_pct = 32
/sys/devices/system/cpu/intel_pstate/max_perf_pct = 100
/sys/devices/system/cpu/intel_pstate/no_turbo = 0

x86_energy_perf_policy: program not installed.

/proc/sys/kernel/nmi_watchdog = 0

+++ Undervolting
PHC kernel not available.

+++ Temperatures
CPU temp = 61 [°C]
Fan speed = (not available)

+++ File System
/proc/sys/vm/laptop_mode = 2
/proc/sys/vm/dirty_writeback_centisecs = 6000
/proc/sys/vm/dirty_expire_centisecs = 6000
/proc/sys/vm/dirty_ratio = 20
/proc/sys/vm/dirty_background_ratio = 10
/proc/sys/fs/xfs/age_buffer_centisecs = (not available)
/proc/sys/fs/xfs/xfssyncd_centisecs = (not available)
/proc/sys/fs/xfs/xfsbufd_centisecs = (not available)

+++ Storage Devices
/dev/sda:
Model = TOSHIBA MK5061GSYN
Firmware = MH000C
APM Level = 128
Status = active/idle
Scheduler = deadline


+++ SATA Aggressive Link Power Management
/sys/class/scsi_host/host0/link_power_management_policy = min_power
/sys/class/scsi_host/host1/link_power_management_policy = min_power
/sys/class/scsi_host/host2/link_power_management_policy = min_power
/sys/class/scsi_host/host3/link_power_management_policy = min_power
/sys/class/scsi_host/host4/link_power_management_policy = min_power
/sys/class/scsi_host/host5/link_power_management_policy = min_power

+++ PCIe Active State Power Management
/sys/module/pcie_aspm/parameters/policy = default (using bios preferences)

+++ Intel Graphics
/sys/module/i915/parameters/powersave = (not available)
/sys/module/i915/parameters/enable_rc6 = 3 (enabled + deep)
/sys/module/i915/parameters/enable_fbc = -1 (use per-chip default)
/sys/module/i915/parameters/lvds_downclock = (not available)
/sys/module/i915/parameters/semaphores = -1 (use per-chip default)

+++ Wireless
bluetooth = off (software)
wifi = on
wwan = none (no device)

hci0(btusb) : not connected
wlo1(ath9k) : connected, power management = off

+++ Audio
/sys/module/snd_hda_intel/parameters/power_save = 1
/sys/module/snd_hda_intel/parameters/power_save_controller = Y

+++ Runtime Power Management
device classes = all
device blacklist = (not configured)
driver blacklist = radeon nouveau

/sys/bus/pci/devices/0000:00:00.0/power/control = auto (0x060000, Host bridge, ivb_uncore)
/sys/bus/pci/devices/0000:00:02.0/power/control = auto (0x030000, VGA compatible controller, i915)
/sys/bus/pci/devices/0000:00:14.0/power/control = auto (0x0c0330, USB controller, xhci_hcd)
/sys/bus/pci/devices/0000:00:16.0/power/control = auto (0x078000, Communication controller, mei_me)
/sys/bus/pci/devices/0000:00:16.3/power/control = auto (0x070002, Serial controller, serial)
/sys/bus/pci/devices/0000:00:19.0/power/control = auto (0x020000, Ethernet controller, e1000e)
/sys/bus/pci/devices/0000:00:1a.0/power/control = auto (0x0c0320, USB controller, ehci-pci)
/sys/bus/pci/devices/0000:00:1b.0/power/control = auto (0x040300, Audio device, snd_hda_intel)
/sys/bus/pci/devices/0000:00:1c.0/power/control = auto (0x060400, PCI bridge, pcieport)
/sys/bus/pci/devices/0000:00:1c.1/power/control = auto (0x060400, PCI bridge, pcieport)
/sys/bus/pci/devices/0000:00:1c.2/power/control = auto (0x060400, PCI bridge, pcieport)
/sys/bus/pci/devices/0000:00:1c.3/power/control = auto (0x060400, PCI bridge, pcieport)
/sys/bus/pci/devices/0000:00:1d.0/power/control = auto (0x0c0320, USB controller, ehci-pci)
/sys/bus/pci/devices/0000:00:1f.0/power/control = auto (0x060100, ISA bridge, lpc_ich)
/sys/bus/pci/devices/0000:00:1f.2/power/control = auto (0x010601, SATA controller, ahci)
/sys/bus/pci/devices/0000:23:00.0/power/control = auto (0x0c0010, FireWire (IEEE 1394), firewire_ohci)
/sys/bus/pci/devices/0000:23:00.1/power/control = auto (0x088000, System peripheral, sdhci-pci)
/sys/bus/pci/devices/0000:23:00.2/power/control = auto (0x080501, SD Host controller, no driver)
/sys/bus/pci/devices/0000:24:00.0/power/control = auto (0x028000, Network controller, ath9k)

+++ USB
autosuspend = enabled
device whitelist = (not configured)
device blacklist = (not configured)
wwan blacklist = enabled

Bus 002 Device 003 ID 0a5c:21e1 control = auto, autosuspend_delay_ms = 2000 -- Broadcom Corp. HP Portable SoftSailing (btusb)
Bus 002 Device 002 ID 8087:0024 control = auto, autosuspend_delay_ms = 0 -- Intel Corp. Integrated Rate Matching Hub (hub)
Bus 002 Device 001 ID 1d6b:0002 control = auto, autosuspend_delay_ms = 0 -- Linux Foundation 2.0 root hub (hub)
Bus 001 Device 003 ID 138a:003d control = auto, autosuspend_delay_ms = 2000 -- Validity Sensors, Inc. VFS491 (no driver)
Bus 001 Device 002 ID 8087:0024 control = auto, autosuspend_delay_ms = 0 -- Intel Corp. Integrated Rate Matching Hub (hub)
Bus 001 Device 001 ID 1d6b:0002 control = auto, autosuspend_delay_ms = 0 -- Linux Foundation 2.0 root hub (hub)
Bus 004 Device 001 ID 1d6b:0003 control = auto, autosuspend_delay_ms = 0 -- Linux Foundation 3.0 root hub (hub)
Bus 003 Device 002 ID 046d:c52b control = on, autosuspend_delay_ms = 2000 -- Logitech, Inc. Unifying Receiver (usbhid)
Bus 003 Device 001 ID 1d6b:0002 control = auto, autosuspend_delay_ms = 0 -- Linux Foundation 2.0 root hub (hub)

+++ Battery Status
/sys/class/power_supply/BAT0/manufacturer = Hewlett-Packard
/sys/class/power_supply/BAT0/model_name = Primary
/sys/class/power_supply/BAT0/cycle_count = (not supported)
/sys/class/power_supply/BAT0/charge_full_design = 2701 [mAh]
/sys/class/power_supply/BAT0/charge_full = 2701 [mAh]
/sys/class/power_supply/BAT0/charge_now = 1209 [mAh]
/sys/class/power_supply/BAT0/current_now = 1617 [mA]
/sys/class/power_supply/BAT0/status = Discharging

+++ Suggestions
* Install smartmontools for disk drive health info

TLP should help significantly. I note that you have BT disabled which is good (most don't use it anyway). Which desktop environment are you using? That might have some impact as well. One other important consideration is screen brightness - lowering that can help with extending battery charge.

DE will definitely affect battery usage...

post output of

legend@legend-HP-ProBook-6470b ~ $ inxi -F
System: Host: legend-HP-ProBook-6470b Kernel: 4.4.0-112-generic x86_64 (64 bit)
Desktop: Cinnamon 3.2.7 Distro: Linux Mint 18.1 Serena
Machine: System: Hewlett-Packard (portable) product: HP ProBook 6470b v: A1019DD200
Mobo: Hewlett-Packard model: 179B v: KBC Version 42.35
Bios: Hewlett-Packard v: 68ICF Ver. F.42 date: 05/20/2013
CPU: Dual core Intel Core i7-3540M (-HT-MCP-) cache: 4096 KB
clock speeds: max: 3700 MHz 1: 1321 MHz 2: 1308 MHz 3: 1536 MHz
4: 1334 MHz
Graphics: Card: Intel 3rd Gen Core processor Graphics Controller
Display Server: X.Org 1.18.4 drivers: intel (unloaded: fbdev,vesa)
Resolution: 1366x768@60.07hz, 1600x900@59.98hz
GLX Renderer: Mesa DRI Intel Ivybridge Mobile
GLX Version: 3.0 Mesa 11.2.0
Audio: Card Intel 7 Series/C210 Series Family High Definition Audio Controller
driver: snd_hda_intel
Sound: Advanced Linux Sound Architecture v: k4.4.0-112-generic
Network: Card-1: Intel 82579LM Gigabit Network Connection driver: e1000e
IF: enp0s25 state: up speed: 100 Mbps duplex: full
mac: a4:5d:36:5b:13:f0
Card-2: Qualcomm Atheros AR9485 Wireless Network Adapter
driver: ath9k
IF: wlo1 state: up mac: 20:68:9d:8a:96:a0
Drives: HDD Total Size: 500.1GB (5.7% used)
ID-1: /dev/sda model: TOSHIBA_MK5061GS size: 500.1GB
Partition: ID-1: / size: 92G used: 20G (23%) fs: ext4 dev: /dev/sda5
ID-2: swap-1 size: 8.44GB used: 0.00GB (0%) fs: swap dev: /dev/sda6
RAID: No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors: System Temperatures: cpu: 33.0C mobo: 0.0C
Fan Speeds (in rpm): cpu: N/A
Info: Processes: 296 Uptime: 12:43 Memory: 1112.7/7846.8MB
Client: Shell (bash) inxi: 2.2.35

that can be a "heavy" DE, try Xfce, Mate, LXDE etc...see if things change/improve. The more bells and whistles the more energy it needs=less energy in battery. Anything based on Gnome3/Gnome Shell is going to be "heavy", I think even KDE/Plasma is lighter now.

How can I change DE?

There are numerous how to's blogs and threads discussing this. XFCE is worth trying first, and new DEs can be installed alongside your existing one. For example
https://www.quora.com/How-can-you-sw...-in-Linux-Mint
https://forums.linuxmint.com/viewtopic.php?t=228637

XFCE features:
https://www.linuxmint.com/rel_sarah_xfce_whatsnew.php