Garmin GPS charge solution
Bob the Wheelbuilder
the life of my Edge 705 on Saturday's San Diego 400K. It worked great
using 2 rechargeable AA batteries. I started the charge after about 8
hours of riding. By the time they had discharged (about 2 hours if I
remember correctly), the battery indicator on the GPS showed full
again. When I finished the ride after 24 hours, the GPS still had
about 1/3 of a charge.
I was able to plug in the charger and turn it on while the unit was
running so it didn't interfere with recording the entire ride as a
continuous file.
Here's a couple of pictures:
http://farm5.static.flickr.com/4007/4419144736_f072c0d049_o.jpg
http://farm5.static.flickr.com/4016/4419144614_88940e2943_o.jpg
I tried alkaline batteries, but they didn't seem to work as well.
They got really hot and didn't seem to transfer as much of a charge to
the unit. Lithium AA's also worked well, but rechargeables seem to be
the best bang for the buck.
I Hope this helps someone else trying to find a solution to charging
during a ride.
Roy Yates
That's very helpful since I've been wondering how those those units work. I do have a question: The cable from the charger battery to the GPS is pretty short. Did you mount the battery unit on the handlebars in some way? If so, do you have any advice and maybe a picture?
Thanks,
...Roy
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Roy D. Yates
Professor, E&CE
Associate Director, WINLAB
http://www.winlab.rutgers.edu/~ryates
Bob the Wheelbuilder
when the unit is mounted, so I took the GPS off my stem and put it and
charger together in the bag during a long, easy-to-follow section.
It still got a signal in the bag and I did check it once in a while.
The charger has 3 lights that show the battery level. A rechargeable
battery only starts with 2 of the 3 lights lit due to the lower
voltage, but the lights do give a good indication when the power has
run out.
I'm thinking of getting a classic front rack mounted bag and I'll
probably use something like a ziplock bag and a velcro strap or
electrical tape to attach the charger to the bar after that.
> Associate Director, WINLABhttp://www.winlab.rutgers.edu/~ryates- Hide quoted text -
>
> - Show quoted text -
J.T. Conklin
> I tried out a cell phone charger I bought at Office Depot to extend
> the life of my Edge 705 on Saturday's San Diego 400K. It worked great
> using 2 rechargeable AA batteries. I started the charge after about 8
> hours of riding. By the time they had discharged (about 2 hours if I
> remember correctly), the battery indicator on the GPS showed full
> again. When I finished the ride after 24 hours, the GPS still had
> about 1/3 of a charge.
>
> I was able to plug in the charger and turn it on while the unit was
> running so it didn't interfere with recording the entire ride as a
> continuous file.
I use a the similar Energizer "Energi to go" charger with my Edge 305.
I too found that lithium AA's work better than alkalines. I have not
tried rechargables.
At least with the 305, I've found that plugging it in with the Edge
fully charged works much better than trying to charge it when the GPS'
battery is depleted. Before I learned to do that, it would sometimes
fail to charge, shut down, or lock up. When I start with a fully
charged unit and new lithium AA's, I get more than 10 hours before it
starts using the onboard battery.
My 305 currently holds about 7 hours of charge itself, so one set of
AA's is good for a 300K at my (slow) pace. For longer distances, I'm
thinking I'm probably going to need to upgrade to a 705 or 500 for
more recording capacity. Before that, I may get a non-recording
cycle computer just to ensure that I'll have a working odometer to
match up with cue sheets in the case of GPS failure.
--jtc
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J.T. Conklin
J.T. Conklin
> That's very helpful since I've been wondering how those those units
> work. I do have a question: The cable from the charger battery to
> the GPS is pretty short. Did you mount the battery unit on the
> handlebars in some way? If so, do you have any advice and maybe a
> picture?
I attached a square self adhesive zip tie bracket to my "Energi to Go"
charger and used a zip tie to loosly hang it to my ortlieb front bag
mount. I mount my 305 on the handlebar close to the stem. The short
cable just reaches. This also seems to protect it from the weather.
We've had rain during all 3 SFR brevets so far, and I haven't had any
problems with water.
I've seen another randonneur zip tie his charger directly to his stem.
--jtc
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J.T. Conklin
Kole Kantner
has dropped steadily to what appears to be a closeout special of $7.97
for two Duracell adapters. They also have the same very short power
cables, although it is very easy to cut the cable and solder an
extension splice in. The Duracell model works well, although I did pull
the wire out of the cable on one due to stresses on the short cable.
Since a fully charged 705 only draws 80-120mA it is much easier on the
batteries to use it while the Garmin is still fully charged. Alkaline
batteries have a lot less capacity at high drain that results from
charging a depleted Garmin battery. The Duracell model does work with
rechargeable batteries, but will not start again once they are only
slightly discharged. It will run the batteries fully down, though, as
long as the adapter is not turned off. Alkalines have the same problem
and will fail to start after about 1.2V at about half discharge.
Lithium AA batteries work best because of the higher voltage. The
Duracell adapter works up to about 5V so it would also be possible to
set up a configuration to use a Lithium Ion or Lithium Phosphate battery
for more capacity, less weight, and less convenience.
--Kole--