I have a Lenovo ThinkPad Edge 13" model 0217-2QG with eSATAp port.
How do i check if my port provides 12V power (enough to power a 3.5" HDD)?
An eSATAp(also known as Power over eSATA, Power eSATA, eSATA/USB Combo, eSATA USB Hybrid Port (EUHP) port combines the 4 pins of the USB 2.0 (or earlier) port, the 7 pins of the eSATA port, and optionally two 12-volt power pins.
__________eSATA port ____________
_____________eSATAp on notebook ___________________
There are two versions of this port. Most laptop computers do not have +12V power available, and have an eSATAp port which provides only +5 V. Desktop computers, with +12V available, have a port with two additional pads, placed against the plug's "horns", which provide +12 V. Some devices, such as 2.5-inch drives, can operate off the +5V supplied by laptop eSATAp ports. Others, such as 3.5-inch drives, also require +12V; they can be powered from a desktop eSATAp port, but require an external +12V power supply if used with a laptop computer. This can lead to confusion if users are not aware of the distinction.
How to check if my eSATAp port provides 12V power?
To know if your eSATAp can supply 12v or no, check the existence of P12 and P13 pins inside the port as it showing in the pictures.
Also you can probe P12 and P13 using DMM(Digital multimeter)
This link provides more detailed information about eSATAp.