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Sony and Wasabi NP-BX1 Li-Ion Battery Life

Using the Sony HDR-AS30V helmet camera more-or-less daily during the bicycling season chews up batteries as well as MicroSD cards:

Sony NP-BX1 - OEM Wasabi - 2015-10-25

Sony NP-BX1 – OEM Wasabi – 2015-10-25

The dotted traces show the most recent status and the solid traces are from almost exactly one year ago:

  • Red = Genuine Sony
  • Blue = Wasabi Power: cell D, August 2014
  • Green = Wasabi Power: cell B, January 2014

All the tests are at 500 mA, approximately half the camera’s load. Oddly, the numeric values along the mA·h axis work out pretty close to the actual runtime in hours:

  • Sony – 1:30
  • Wasabi D – 1:15
  • Wasabi B – 0:40

Given that a typical bike ride takes an hour, the two year old Wasabi B battery’s 40 minute runtime isn’t useful. The Wasabi D battery is a bit over a year old and looks very much like the B battery did last year.

The Wasabi batteries march through the camera and charger in order, so each one gets used about once a week. The Sony battery gets used once every half-dozen complete cycles, just so I have a standard “good” battery.

The Sony and Wasabi B cells over the course of two years:

Sony NP-BX1 - OEM Wasabi - 2015-10 2014-10 2014-01

Sony NP-BX1 – OEM Wasabi – 2015-10 2014-10 2014-01

Much to my surprise, the Wasabi batteries started out slightly better than the Sony OEM battery, at least as measured by the available voltage and energy. The camera runs from an internal switching power supply, so the area under the curve (basically equal to energy in W·h) above the cutoff voltage is all that matters.

In round numbers, I can expect 100 cycles out of each battery before the run time drops below the ride time; at $10/battery, that’s a dime a ride. Any claims that the batteries can be recharged “1000 times!” may be true, but they’ll have a useless fraction of their original capacity by then.

Time to buy a few more batteries…

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  1. #1 by Mike on 2015-11-03 - 19:47

    Would it make sense to put gut one of the old dead batteries, drill the case for a piece of zip cord and put together an external battery pack ? I’ve done that with a few pieces of equipment that used expensive or hard to get batteries.

    BTW many of the chinese and hong kong 18650 cells are junk (nowhere near their rated capacity and many fail completely within a couple months).

    • #2 by Ed on 2015-11-04 - 08:59

      The cover slides sideways to unlatch, then pivots on a complex offset hinge built into an assembly holding the Record button (and its latch) that also mechanically backstops the battery. It’s a clever design; if you didn’t know better, you’d think Sony deliberately prevented cheaters. You’d need a long slot through the case along the side wall of the battery compartment to sneak a cable past all the mechanics.

      The camera draws charging power through its micro-USB connector and only the magic Sony external supply can boot the camera into full-power operation. From what little I can find out, it’s more complex than just yanking the USB Data/Clock lines one way or the other like everybody else does.

      many fail completely within a couple months

      Surprise!

      • #3 by Mike on 2015-11-04 - 12:32

        Would it be worth trying to rebuild one of the dead batteries with some new cells?? The old battery is ewaste anyway, wouldn’t hurt to dissect it . . .

        • #4 by Ed on 2015-11-04 - 12:47

          None of my usual sources carry tiny prismatic cells for camera batteries, but I admit to not spending a lot of time looking elsewhere.

          Anybody have a pointer?

          And, yeah, I should tear one apart just to see what’s inside… [grin]

      • #5 by eriklscott on 2015-11-04 - 16:45

        Trying to visualize this and failing, but… could you (1) gut the battery, (2) re-wire the innards to an MCX connector (or another suitably tiny part) on the side of the battery, (3) drill a hole in the battery cover large enough to admit the MCX plug and, (4) profit! They’re about 0.15″ diameter and used sometimes for cellphone antennas. I don’t know what sort of DC power they’re rated at. :-)

        Wind a couple of coils and do some wireless power? There’s always a way.

        • #6 by Ed on 2015-11-04 - 19:56

          an MCX connector

          I think they’re rated for something like 10 connect cycles, but, yeah, I like the idea: thanks for the suggestion!

          The camera draws just shy of 1 A from the battery (without GPS/WiFi/etc), so the connector needs more starch than found in the usual flea-size contacts. A side connector, no matter how ugly, would be less awful than stuffing 5 V (-ish) through the micro-USB jack, which always looks ready to rip off the board.

          • #7 by eriklscott on 2015-11-04 - 22:37

            I’ve found that the cable tends to fail before the connector actually wears out, but cycle life is a problem. I think I looked and Amphenol rated theirs for something like 100 cycles, which is about four months for you. Makes me wonder, though – does that mean it fails mechanically, the contacts become intermittent, or just the impedance through the connector changes (maybe from displaced insulation)? I have no idea.

            • #8 by Ed on 2015-11-05 - 08:01

              Whoops. I read MCX and saw U.FL, which is an entirely different thing… objection withdrawn!