Studio XPS 1640 Battery Life

So, first off, I know that everyone has different configurations and such, so while that does have an impact, I still want to know what is the general ballpark battery life you guys are getting. From what I am seeing, 2 hours is the average for the 6 cell, whereas the 9 cell is only 3?

I ask because as strange as it sounds, using BatteryBar indicates that the 6 cell that came with my 1640 has a capacity of only 5100mWh! That sounds very strange, because I know that on my XPS m1530, the 9 cell had a capacity of nearly 86,000mWh. I am having a 9 cell sent to me for my XPS 1640, and hopefully that will fix things. Maybe the battery's circuit board is reporting the numbers wrong/shrug.

 

I get about 2hrs from the 6 cell

 

For web browsing I get about 2:30, for anything demanding 1:30 is about the limit, the most I've even seen was 3:20 when I got it new (everything turn to min, compleetly idleing). I have the six cell, my specs are in my sig.

Does the 4670 get better battery life?

 

So let me ask you guys, can you please install this program? It is a battery gauge program that can tell you specific information about your battery: http://osirisdevelopment.com/BatteryBar/

What confuses me is that the term "mWh" means milli-watt hour. Milli means 1/1000, so therefore 85Wh should imply 85000mWh. Yet, for me BatteryBar reports the 9 cell 85Wh battery has a capacity of 7800! I mean, the 6 cell showed a capacity of 5100, and it did last me about two hours.

Can you guys install this, and then please tell me what is the capacity of your batteries? I'd appreciate it.


EDIT: Nevermind. It appears to be related to how the battery is reporting its capacities. It is reported here: http://osirisdevelopment.com/forum/thread-54.html (not by me). The odd thing is that if I use another tool such as Lavalys EVEREST it also shows the 7800 capacity...

 

It's probably battery wear

 

It isn't battery wear, it's a brand new battery. As I said, it is reporting current instead of wattage.

 

I used to get about 4.5 hr withi lowest brightness, power saver
9-cell

I believe after using my laptop unplugged a couple of times in school using almost 95% of the battery, I think the capacity dropped a bit.

HWMonitor currently shows 7368 mWh fully charged out of designed capacity of 7800 mWh. I think it was ~7500 mWh before that. =/

I can still get 3.8-4.0 hrs at low power settings.

(Again, this is for a 9-cell for my XPS 1640)

 

I get 2 hours or so depending on how I use it off the 6 Cell. If I watch Hulu I get an hour to an hour and 20 min or so.

I might pick up a 9 Cell off eBay.. Been thinking about it for a while now.

 

So I just ran a battery test to see how long it would last. Using the normal Power Saver profile in conjunction with the Dell Battery Meter software (audio power management on, which turns off the speakers unless you play a sound, and also turns off optical drive), keyboard backlight off, and screen at 30%, I had 8 Chrome tabs open and using pagereboot.com had each of them reload several websites (for my test: Lexus, Acura, Dell, Facebook, Mercedes, BMW, Honda, and Woot), the battery lasted for:

5 hours!

Of course, this number just shows the most optimistic battery life you can get out of the laptop, assuming you are running nothing other than your browser. I attribute the high number also due to the fact that the Power Saver profile has the CPU locked to its slowest speed. Granted, for all the websurfing, the low speed was barely noticeable.

One interesting thing to note, though, is that the Dell booklet that came with my 1640 said that the Power Status rings on the LCD hinge are supposed to change from white to amber(low), and then blinking amber (critically low). However, for mine, it skipped the solid amber, and went straight from white to blinking amber (critically low) at around 10%. Odd.

Now to recharge the 9-cell I used for this test... BatteryBar says 7.5 hrs :O....

EDIT: It took only 1.5 hours to get to 90%, which is a surprise. However, I am seeing a near 5% drop in battery capacity, time to go on Dell Chat

 

Yeah I can get 4 to 5 hours with my 6 cell on power saver and lowest brightness. Anywhere from 2 to 4 hours under normal usage/medium brightness/balanced. Pretty sure the P-series C2D's and the 4670 help battery life as all the reviews had this laptop pegged for two or three hours tops.