Yes...Yahoo is killing the battery. Here's some vital info from flcabrio from another post:
I was very happy with my battery life before I added Yahoo contacts. I could go about 2 days without having to charge. As soon as I added Yahoo contacts, my battery started draining like crazy, so I ran a little experiment.
With Yahoo contacts added:
11/14 2am - 54%
11/15 7am - woke to dead battery. (only 5 hours later.....not good)
Removed Yahoo contacts:
11/15 10:30am - 95%
11/15 6:30pm - 70% (8 hours later.......much better)
Readded Yahoo contacts:
11/15 6:30 pm - 70%
11/15 10:30 pm - 24% (only 4 hours - Definitely draining fast)
Removed Yahoo contacts and recharged
11/16 7am - 100%
11/16 3:30pm - 76% (8 1/2 hours later - good battery life)
Yahoo contacts is definitely the culprit. I really wish it would work, because I use Yahoo for everything, but I can't be charging my battery every 4 hours. Palm still has some work to do.
I can confirm that with Yahoo contacts I was losing over 10% battery power per hour under my normal usage pattern; more than double my norm. After unintstalling Yahoo contacts, I lost only 1% this past hour.