after setting apm_battery=128 in my /etc/hdparm.conf 
as well as in  /lib/hdparm/hdparm-functions:
            if hdparm_is_on_battery; then
                hdparm_set_option -B128

Here is what I get with sudo hdparm -I /dev/sda

	Advanced power management level: 1

Complete log: apparently, same HD as Swâmi Petaramesh above

/dev/sda:

ATA device, with non-removable media
	Model Number:       SAMSUNG HN-M101MBB                      
	Serial Number:      S2RQJ9ABB07710      
	Firmware Revision:  2AR10001
	Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
	Used: unknown (minor revision code 0x0028) 
	Supported: 8 7 6 5 
	Likely used: 8
Configuration:
	Logical		max	current
	cylinders	16383	16383
	heads		16	1
	sectors/track	63	63
	--
	CHS current addressable sectors:    1032129
	LBA    user addressable sectors:  268435455
	LBA48  user addressable sectors: 1953525168
	Logical  Sector size:                   512 bytes
	Physical Sector size:                  4096 bytes
	Logical Sector-0 offset:                  0 bytes
	device size with M = 1024*1024:      953869 MBytes
	device size with M = 1000*1000:     1000204 MBytes (1000 GB)
	cache/buffer size  = 8192 KBytes
	Form Factor: 2.5 inch
	Nominal Media Rotation Rate: 5400
Capabilities:
	LBA, IORDY(can be disabled)
	Queue depth: 32
	Standby timer values: spec'd by Standard, no device specific minimum
	R/W multiple sector transfer: Max = 16	Current = 16
	Advanced power management level: 1
	Recommended acoustic management value: 254, current value: 128
	DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
	     Cycle time: min=120ns recommended=120ns
	PIO: pio0 pio1 pio2 pio3 pio4 
	     Cycle time: no flow control=120ns  IORDY flow control=120ns
Commands/features:
	Enabled	Supported:
	   *	SMART feature set
	    	Security Mode feature set
	   *	Power Management feature set
	   *	Write cache
	   *	Look-ahead
	   *	Host Protected Area feature set
	   *	WRITE_BUFFER command
	   *	READ_BUFFER command
	   *	NOP cmd
	   *	DOWNLOAD_MICROCODE
	   *	Advanced Power Management feature set
	    	Power-Up In Standby feature set
	   *	SET_FEATURES required to spinup after power up
	    	SET_MAX security extension
	   *	Automatic Acoustic Management feature set
	   *	48-bit Address feature set
	   *	Device Configuration Overlay feature set
	   *	Mandatory FLUSH_CACHE
	   *	FLUSH_CACHE_EXT
	   *	SMART error logging
	   *	SMART self-test
	   *	General Purpose Logging feature set
	   *	64-bit World wide name
	   *	IDLE_IMMEDIATE with UNLOAD
	   *	WRITE_UNCORRECTABLE_EXT command
	   *	{READ,WRITE}_DMA_EXT_GPL commands
	   *	Segmented DOWNLOAD_MICROCODE
	   *	Gen1 signaling speed (1.5Gb/s)
	   *	Gen2 signaling speed (3.0Gb/s)
	   *	Native Command Queueing (NCQ)
	   *	Host-initiated interface power management
	   *	Phy event counters
	   *	Idle-Unload when NCQ is active
	   *	NCQ priority information
	   *	DMA Setup Auto-Activate optimization
	   *	Device-initiated interface power management
	   *	Software settings preservation
	   *	SMART Command Transport (SCT) feature set
	   *	SCT Long Sector Access (AC1)
	   *	SCT LBA Segment Access (AC2)
	   *	SCT Error Recovery Control (AC3)
	   *	SCT Features Control (AC4)
	   *	SCT Data Tables (AC5)
Security: 
	Master password revision code = 65534
		supported
	not	enabled
	not	locked
		frozen
	not	expired: security count
		supported: enhanced erase
	210min for SECURITY ERASE UNIT. 210min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 50024e920670e1bf
	NAA		: 5
	IEEE OUI	: 0024e9
	Unique ID	: 20670e1bf
Checksum: correct