powering using usb

Is it possible to power the sportrak pro with a usb connection? I have a
cigarette lighter power cable that works connected to a solar cell with a
sportrak pro.
Dave

Noweldrecumbent2 wrote:

The external power input for the SporTraks and Meridians is 3.3 to 3.8V
from the OEM cigarette lighter power adapter. So the input voltage from
a USB port, at 5V, would be too much and you would run some risk of
damaging the GPS receiver.

The Meridians and SporTraks all use the same "Power Cable w/ Cig. Ltr.
Adapter", you can see that here:

http://www.magellangps.com/products/accessories.asp

That adapter has a small, rectangular box along the cable. That box
contains a DC-DC inverter that drops the 9-35V input voltage to 3.8V (by
my actual measurements, Magellan does not mention what it is). The DC
3.8V voltage at the connector probably drops a little under load, that
is why I say it needs 3.3 to 3.8V. Somewhere in the Meridian or
SportTrak manuals or spec sheets, those are identified at needed 3.3V
for DC power.

And they will not charge the batteries when they are externally powered.
That is a good thing because they are intended for use with
non-rechargeable alkaline batteries. And bad things can happen when you
try to recharge alkalines.

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

I noticed that on my sportrak pro cigarette power cable. I was hoping I
could use the proporta mobile survival usb supply to power it like it does
the pda, clearly not going to happen. Do you know if the serial cable is
strickly communications, or power also? Thank you for the information. I
managed to pick up a used meridian from ebay, hope it's as good as the
sportrak I bought awhile back.
Dave

Noweldrecumbent wrote:

Any DC power source of the right voltage (3.3 to 3.8V) can be used.
Those numbers are not consistent with a USB port (5V) but you could make
or maybe buy a DC-DC inverter that would drop the 5V from a USB port to
3.8V and then you could use it. If your aim is to use one power source
for the GPS and PDA, I'd pursue the voltage dropping inverter.

If you're using the Meridian primarily as the NMEA input for the PDA you
don't need the display on. And in that case, you can get through a
pretty long day (10-12 hours? or more?) on a pair of AA cells.

Jack

That is my goal. Bicycle touring is alot easier when integrating things to
work together instead of carrying a bunch of different things. I have a
bluetooth SirfII for the pda but mainly use the Magellan, battery life on
the pda is limited, and it does not provide the topo features the dedicated
gps units can. I'll look around for a gps/mobile supplier that can hook me
up with a inverter. Thanks for your help.
Dave