I thought I should share this for anyone that has a need for an external power pack for an extended time shoot or as a backup power during hiking.
From looking around, I knew that a Sony AC adapter supplies 7.6v to the camera. Most power power pack that I've looked at that cost around $80 + additional parts.
Yet, they don't provide the crucial correct voltage to the camera and still too bulky to wear around the waist or attach to a tripod.
I bit the bullet on this $24 bicycle LED light with rechargable power pack rated 8.4v which is closest to 7.6v required.
Bought an after market AC adapter for Sony $14
For the last part, I could have bought a DC male to male 2.5mm adapter for $3 but decided to use spare parts that I had laying around.
(cut off to use the end part of an old AC adapter for computer speakers + a connector)
My total cost is under $40...and have an LED light as a bonus
The good news is that the 8.4v power pack measured at 7.6v...perfect!
Now, I've not had a chance to test out how long it powers my camera.
The unit has 4x 18650 batteries rated at 6400mAh.
Though, I wouldn't careless if it actually has 3/4 of its rated mAh.
That's plenty enough for me to tether, time lapse or video shooting without worrying of power interuption.
I will probably need to spring $50 for that Capture One PRO for Sony to utilize LIVE VIEW capture tethering with Surface Pro 3.
This is the LED light with rechargable power pack, sleeve. (2 included rubber band loop use to attach bicycle's handle bar not in picture)
This is the third party AC adaptor for Sony + home mod DC male to male adaptor
This is how it looks like as connected
Measured 7.6v before insertion
Tethered with Surface Pro 3 (sorry about the last 2 pictures are out of focus...I must tired )