Pages: [1]   Go Down

Author Topic: MBP Digital Station for Location - Battery Management  (Read 802 times)

markjhn

  • Newbie
  • *
  • Offline Offline
  • Posts: 7
MBP Digital Station for Location - Battery Management
« on: April 16, 2014, 08:46:09 am »

Using a 2011 MacBok Pro 15" as our digital station for on location catalog shoots, running off a first generation Hyperjuice 222wt external battery pack (which doesn't provide the full draw of power needed when the MBP is in full swing), using Apple's Airplane adapter (provides external power but not the charging of the internal battery).  Hooked up to this is a card reader and bus powered Firewire 800 G-Tech for backup during the import of images.   Typically this works ok though when the MBP is ramping at full throttle, it does pull power from it's internal battery rather than the external.  As such it's been pretty good running for the full 10 hour day of ingesting CF cards into an Aperture library, browsing/editing and tagging images with the AC freshening of batteries during lunch.  At best the external battery runs down end of day leaving ~30% or less of the internal battery to finish out the last shot. 

In my quest for speed, stability (no moving parts, no worries of moving the computer and messing up spinning platters and heads) and efficiency, I installed a Crucial M500 960GB SSD drive which greatly increased performance and speed of the system, but on this current shoot I noticed that the MBP internal battery was drawing down to 25% before noon, while the external battery was still pretty full; the opposite of of previous shoots.  My only guess was that the MBP was pulling it's full draw more frequently, exceeding the external's battery's ability to supply power.  I was also using a LaCie Thunderbolt Rugged drive for my backups, again assuming the benefits of speed via TB.

After digging and researching, it appears that the Crucial SSD actually uses more power at idle than a conventional hard drive.  It's two states are either ON or OFF as opposed to variable rates of a hard drive.  I knew that ON pulled the full amount of power, and assumed OFF would be next to nothing with no spinning hardware to power and hence thought this be the most efficient with regards to battery life.  What ever speed I may have gained, I lost precious battery life as a result.  On top of that, running a TB connected drive uses more power than FW due to the current draw and needs of the TB system/cable.  Apparently all my assumptions were only half right; I got the speed of SSD and TB, but at the expense of battery life.

This is not to say that a SSD based system won't work; there are other SSDs that don't have the same power characteristics as the Crucial M500, but I'm not sure of their benchmarks etc...

I've re-installed my hd, back to the FW800 backup drive, and daisy chaining a FW800 Sandisk CF reader for the second half of this job.  I'll update it with my results.  Who knows, maybe the culprit is the Hyperjuice battery controller board having gone bad (note;  1.5 version of their batteries ARE capable of supplying the full power requirements of the MBP).
Logged
Pages: [1]   Go Up