On Aug 5, 11:44*am, Martin Gregorie
wrote:
On Wed, 05 Aug 2009 11:11:47 -0700, Andy wrote:
On Aug 5, 10:10*am, MarkHawke7 wrote:
I'm trying to get a direct answer from my contacts at SPOT

Mark,

Since you have contacts there I'd be interested to know why they changed
from 2xAA to 3xAAA cells. *Was case size the only consideration, or
perhaps the increased voltage increases the uplink TX power? *In any
event I'd far rather have the longer life of AA cells than a smaller
case size.

I suspect we're in the minority and Joe Hiker would far rather have small
and light than long battery life.

Hopefully the Mk 2 will provide the best of both worlds, which would be
either:
- add an external power socket while retaining the 3 x AAA internal
* cells

- replace the AAA cells with a 1500 mAh LiPoly rechargable and
* a mini-USB charging socket. Alkaline AAA cells are 1250 mAh.

All hiking-type Garmins have internal batteries with an external power
connector, so IMO its odd that Spot doesn't.

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

Their choice of a primary Li battery is completely understandable
given their assumption the device is mostly for occasional use and an
emergency signaling. The e2 Energizer Li-FeS2 batteries have much
longer shelf life than a rechargeable Li batteries. SPOT is slow to
wake up to realize tracking is the killer application in lots of
different areas maybe they know much more than we do about their
customer usage (but I'm not so sure).

I also suspect the move to AAA batteries was purely based on packaging
size. The new AMY-5M GPS chip used in the new SPOT SPOT can operate at
1.8V or 3.0V, and the old STX-2 Axionn chipset that drove the original
SPOT messenger was a 3.3V device. No sign yet on an upgraded STX
module announced from Axionn, and they may not have done much to the
Globalstar data-out side of this except improve the GPS/Globalstar
antenna as they claim. Going to a higher nominal internal voltage
would be pretty unusual (i.e. is not likely to be the driving reason
for using 3x AAA). A quick disassemble will tell a lot.

If I was SPOT I'd be looking to charge significantly more for external
power + altitude and other features.

Darryl