I find the battery life on my Mogul is much improved over the 6700. It is my opinion that if you are having battery issues it is most likely a bad battery or a lack of familiarity with WM devices. These little computers use a lot of power to do some things and if not used properly can kill the battery. I get about 3/4 of a day out of my Mogul battery but I am a heavy user, I would go through 3 battery's every day on my 6700 even after tweaking all the battery saving functions. So after 3/4 of a day I plug my Mogul in and in 4 hrs its filly charged or in one hour I am at like 1/2 charge. I noticed that from 1/2 to 0 takes a lot longer than on my 6700. To those having battery problems do you ever let the battery get to the battery warning before recharging? On my Mogul it seams like the last half of the battery lasts longer than the first half.

I don't see any issues with my battery life either. Obviously, this device is going to use some battery power. It's a small computer... what do you expect? There are ways to conserve your battery life and I would recommend you try them. I've set my IR Beam to off and keep my screen brightness on 75% brightness when running on battery and my 6800 holds it's charge all day with moderate to heavy use. I've never had it fall below 40% charge by the end of the day. I leave it on the charger all night while I sleep, and when I wake up, I pull it off the charger and start over again.

My email response to HTC
 

I sent this to HTC:

Thanks for getting back to me so quickly. A couple of things though:

1. I was told at the Sprint store that they have no available batteries to offer at this time for replacement. So.......
2. It troubles me that you note "use the original wall charger to charge the device for at least and not more than for four hours." Why four hours? Does the charger not shut off or trickle charge once the battery is fully charged? Who is going to watch the charger for that amount of time and make sure that only 4 hours have gone by? If more than 4 hours, what then? Every other phone I have had, did not have a requirement of removing from a charger once it was fully charged.......
3. I have a 2-3 bar signal at my home - the ONLY thing on is my phone - NOTHING ELSE IS ON - the phone will only stay charged for about 1 1/2 - 2 days. This does not fit the stats that HTC publishes for the phone (up to 200 minutes talk time and up to 9.5 days standby time). Something is not correct here and I would like some answers since I have invested my time and money in your company's product. What can be done?

just like the 6700, you're gonna have to buy the extended battery...

or a spare standard battery.

My Mogul is 2 days old. I have a very weak signal at work. My battery is dying really fast. It went from 100% to 80 in less then 2 hours. I disabled BT, Wi-Fi, roaming and lowered brightness to about 50%, adjusted battery settings. I also disabled direct push. Yesterday it went from 100% to 30 in 8 hours with very light use. I think it is dying that fast because the signal where I work is very weak and the phone constantly looking for a signal. Is there a way to disable this?

This is my first PDA. My Sanyo M1 was holding battery pretty well for those 8 hours at work.

My battery is also having issues.
I disabled my location service (e911 only), which is something I haven't seen people suggesting, but it should help SOMETHING.
To everyone saying disable bluetooth, etc... That's bunk because I'm coming from using 2 GSM Windows Mobile devices, and I never had to disable BT to make my battery last through the day before! I know that CDMA uses slightly more power than GSM does, but there is something more going on here. Its not something as simlpe as disabling BT, IR, etc... (my older WM devices had those on 24/7 and I was still able to get a couple of days out of a charge with them).

I did notice that with my phone sitting on my desk, it will randomly power up itself! I'm not sure if this has something to do with the weak signal going in and out of roaming, but whatever it is, its definitely NOT helping the situation!
Has anyone else noticed this happen? Try leaving your phone out where you can see it, and see if the backlight turns on all of the sudden randomly.

You are not supposed to drain a Li-ion battery to 0, that would actaully damage the battery

try forcing it to 1xRTT mode only and see if that help, search for it on the forum

try putting your Mogul in flight mode when you are not using it, I have noticed that my Mogul uses a lot of battery when it is trying to get or maintain a signal in areas like yours.

Sorry, but that's a very strange thing to say.

I come from owning a long line of Palm Treos and without exception they have all been able to sustain at least a full day's worth of moderate use, including 30-60 minutes of call time, constant push email, light web browsing, casual RSS and ebook reading, and still get home at the end of the day with a comfortable 40%. I never had to turn bluetooth off, ever.

My Mogul is like a baby. I have to turn bluetooth off and have the screen at one of the dimmest levels. Having push email and no call time whatsoever gives me 7 hours' battery if I'm lucky. If I make any phone calls that rapidly drops to 6 hours or less. Do anything else - read RSS feeds, light browsing for a couple of minutes - and I'm looking at 5 hours to a dead battery. I've had it last as little as 4 hours.

Asking the user of a phone to switch it to flight mode so it will last a day is just not reasonable. This has nothing to do with knowing how to use a device. It's just poor performance and very low standards, period.