Despite my last post about running sans GPS tracking device, I'll put this out there for anyone who is looking to track their data in events that may outlast their GPS battery life.
I have the Garmin 405. While it is a great watch with good form factor, the battery life is probably the lowest in the Garmin series. I have yet to hit their reported 5 hour life without the little warning beeper going off. I read on one of the blogs listed in this forum about the Duracell Instant power device so I can't take any credit for coming up with the idea. Nonetheless, it seemed like a good one so I went out and got the battery pack and road tested it this weekend.
The device itself is relatively inexpensive. I bought mine at Staples for about $32. I'm sure you can get it on-line for much cheaper. The form factor is very small. At 3.5in x 1.75in x .25in, it is smaller than a cell phone and weighs next to nothing. You charge it from your USB on your computer and then, you are ready to go. On the road, you simply plug in the USB charge cable from your device, attach the business end to your watch, turn the battery on and that's it, your re-charging while running. The good news is that the Garmin continues to gather data while you are charging so you don't need to worry about losing any information. It took me about 40minutes to go from about 15% charged to the full 100%. I then used the battery to re-charge at home. I'm not sure how many full charges the battery holds but, I suspect that it is at least 2 if not 3. That brings my 405 from 5 hours to potentially 20 if you start with a full charge.
Thanks to Chris J. for alerting me to this thread and this forum. One question re the "charging on the fly" issue: my current Garmin the 310 (which yes gets up to 20 hours but no doesn't get me through 100 milers--not that fast!) has an issue similar to other Garmin models I've had. It's very sensitive to getting bumped when you're recharging it (indoors), if you don't place it sort of in a spot on flat surface where it won't get jarred. If jarred, it stops re-charging and/or turns on and looks for the satellites (and sucks battery life) rather than staying off and continuing to re-charge.
Do you find that you have similar issues of "firm connectivity" between this Duracell device and the watch while running? I've heard people mention this or similar devices, and heard people describe how they rig some sort of system to their sleeve to carry while running. but haven't heard about this particular issue.
I think I've also heard that during the charging or at some points you can't actually view the watch but that, as you say, it is still tracking the data and will show it on the screen (ie elapsed mileage) once it's fully re-charged. Is that what you've found?
Thanks for the post Scott...
I havent had the issue with jarring on my 405. I simply clip the charger to my watch and battery and keep going. I've prefer to keep my watch on my wrist and think the pressure from my wrist helps to keep the charger attached. I also think keeping the watch / battery on my arm reduces the jarring that the device might experience if it were attached to a pack.
It is true that you cant see the data while the charger is plugged in but, mile splits do pop up during the charging process. If I find that I need more information than that, I just unplug the charger for a few seconds to read the data I might want to see. And yes, the data keeps recording on the device so you can upload the whole event to review/share through the Garmin website.
Still, a bit annoyed with managing the long cord, dealing with the clip that attaches to the watch and the short battery life of these devices in general but, I suppose the watch is doing quite a bit of work tracking satellites etc.
Garmin also makes a charging kit but, it is far more expensive than this setup.
Best of luck in rigging your device and more importantly, your long runs.
I used the Duracel packduring The DWG 50k. I left the pack and the
watch (405) in the top pocket of my Nathan pack. The wire unclipped
itself from the watch due to the pounding.
Keeping the watch on my arm would have prevented this from happening
but I do not want to deal with wires.
I found an easy fix: a rubber band or a twisty tie thing around the
clip to firmly maintain it on the watch!