Just looking for some recommendations, need to charge 735 probably 1-2 times during an ultra.
Best charger for this?
Any tips on keeping the unit attached to the charger while running?
Thanks
I did a 200 mile race last month, on the bike for around 12+ hours. I purchased a small/compact “Pocket Juice” external battery charger from Best Buy. I taped it to the top tube (on top). I left my Garmin 800 cord in the unit, taping the cord down my top tube. Whenever it got low, I simply reached down, grabbed the USB that was taped one inch from external battery charger, and plugged it in … and I did this while racing. Super easy. After around 30 mintues, I just reached down, took it out of the battery charger, and secured the tape on the cord back on my top tube … again, while riding.
I’ve tested this since on 3 170+ mile rides. Never had an issue. Hope this helps.
Not sure if the 735 can be charged easily during the run. I have been able to charge the fenix 3 during an extreme tri using the charging cable and a external battery pack. The charger fits under the watch while it is on your wrist. Display went to the charging screen, but my auto lap notifications still showed up. After full charge, I removed the cable and display was back to normal.
Geez, I totally misspoke. I assumed you were on the bike! Never mind anything I said 
Sell it and get a 935 - 24 hours of battery time in GPS mode. That’s essentially what I did (replaced my 235 with a 935). I figure that’s at least enough to get me through 100k’s. Haven’t tackled a 100 miler and don’t plan to for a few more years so I’ll worry about that then.
Before getting the 935 my plan was to have a second watch (my wife’s) ready to go around the 50k point and swap out. Never like the idea of charging mid-run with a battery pack.
pretty simple. i’ve done it on my 405 and with the Fenix 3. Biggest thing is to make sure you CAN charge while in use. Some watches will automatically end your run if you put them on a charger. Here’s a decent list, which was recently updated:
http://runallthetrails.com/2015/03/best-gps-watch-for-ultrarunning/
I just finished my first 100 mile run a couple weeks ago in just under 27 hours with my Fenix3 HR. It was giving me BS readings in UltraTrac mode and the course wasn’t marked so I needed the distance to be accurate to follow my cue sheets so I had to run it in GPS mode. I charged it twice along the way using an external battery pack. I did this in aid stations while sitting down since I knew it would be a good excuse to give me a 30 minute sitting rest but I certainly could have charged it along the way if I wanted/needed.
I don’t have your 735, but with the Fenix3 you can access all the regular watch features while running and charging by going to settings/system/USB Mode/ and then pick Garmin instead of Mass Storage.
Good luck and hope this helps!
Thanks for all the info. Did a test run, seems to charge ok on the fly.
Will probably upgrade to the 935 at some point, but for now this will work.
Cool.
The people I know who do this sort of thing just put the watch in lock (hold up on the up button, lock device), put on the clip and throw it in the pack for a bit.
The 735 charges so fast (possibly due to the anemic battery), that you could probably fill it up in an hour.
Which race?