Garmin 305 Battery Life for Ironman

How important is it to you to have it on for the beginning of the bike?  Do you think you can pace yourself well for the start of it without it on?

I think I'd just turn it on while you're on the bike.  Then actually start it when you pass a specific distance marker. (I haven't done an ironman, but I assume they still have distance markers at various points?)  You won't have data for the start of the bike, but you either have to give up part of the bike, or part of the run, right?

I've turned my garmin on while driving in the car, and it eventually gets the satellite signal.  It takes longer then when I'm staying still, but it's there eventually.

Turn it on in T2 and take off.  It'll be wrong for a little while (and the avg will be off for a little bit) but it'll slowly correct as time passes.

And if your 305 lasts 10 hours yours is better than mine was.  The most I ever got out of my 305 was 8 hours.  The 310XT ran my entire IM plus still had 1/3 of battery left.

Turn it on before the swim to find the satellites, then turn it back off.  My 305 always seems to find them quicker if it has already found them in a given location.  Then turn it on as soon as you hit T1.  Assuming a moderate T1, the worst case is that it will be wrong for a few tenths of a mile on the bike, which shouldn't affect your overall pacing much.  Just look for the first distance sign on the bike and compare it to the Garmin display.

My 305 gave me my first low battery warning at about mile 25 on the run.  It made it all the way through my IM (~10 hours not counting the swim) and died very shortly after.  My wife's made it a longer time,  at around 13 hours not counting the swim, but didn't make it to the finish line.

This was my thought going into my first IM.  But then I thought, I have a cheap Timex I will use for the entire race to keep overall time, I have a bike computer so what do I need the Garmin for?  But I do use it for the run.  I'm just used to running with it.  Keeps me honest, otherwise I slow down   And yea, I start it when i leave T2 and it finds a satellite OK.  Again, just need it for pace so I don't need the instant on.

enjoy,

Duane

I have a 305, and I've considered doing this exact thing for IMLP this year.  Supposedly the GPS being turned off can save a good amount of battery.

But as someone mentioned, there is an article by dcrainmaker for extending the battery life.  This year for christmas I asked for a battery pack - I'm considering keeping the 305 plugged into that for the bike portion so it's fully charged when I set out on the run.

The 305 doesn't seem to lock into the charging dock very well and it looks like the charging pack is a connection made to the charging dock rather than the actual watch. Seems a bit risky on a 5-6 hour bike ride with all the bumps and potential for ejection.

Mine lasted 10 hours. If not using GPS on the bike is an option... then I don't see why you can't just use a good ole G-shock for time keeping. Use the 305 for run management.

And why do you think you need to stand around... I got so sick of waiting for aquisition I just go. It catches up and it works out. It still records starts and stops and is accurate for what we do... I mean accurate for not trying to drop a bomb on someones head.

That's exactly why I went the way I did.

Yes, thats true - I'm thinking either zip ties or a few rubber bands.  Still debating the whole thing, though.