Archive for November 3rd, 2015

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…