Realistic Battery Times for X61t

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xaveon · #1 Post by **xaveon** » Sat Jul 14, 2007 11:27 pm

Hey guys,

I have a X61t with the 8 cell battery. I've been reading the forums that everybody is getting about 6 hours under normal use. Is this true???? For some reason I am only getting 4 hours. Even when I turn off all wireless (switch) and set the power "Maximum Battery Life". The battery only has 27 cycles on it. I have two 8 cells and they perform the same way. So I'm thinking it's some kind of setting on the x61t. Or maybe a hardware issue. I am calculating this according to what the battery meter displays. I haven't had time to do a real life test. Could it be that the battery meter is not accurate? What do you guys think? Can someone please tell me what kind of settings you have that's allowing you to yield 6 hours? Thanks a lot

mgags7 · #2 Post by **mgags7** » Sun Jul 15, 2007 11:42 pm

I'm firstly wondering how you've already cycled that battery 27 times, I thought the first of us to get x61ts got them about a week and a half ago.

Anyways, mine gets about 5.5hrs with the brightness down to like 3 and surfing so the wifi switch is on.

Post up something like this and lets take it from there:
Full charge capacity: 72.66 wh
current: .64 A
voltage: 16.08 V
wattage: 10.5 W

I'm not sure how familiar you are with electicity, but current * voltage = wattage. The 72.66 wh means that you have 72.66Wh/10.5W hours of power. As it was when I took those numbers, the computer said about 5.5hr of life, but the math says I have more like 6.5h or a tiny bit more.

SFWrtr · #3 Post by **SFWrtr** » Mon Jul 16, 2007 12:20 am

I have both the 4-cell and 8-cell battery for my X61 tablet. I typically have wireless turned on, but otherwise use max battery when not plugged in (though I have the display at middle-bright).

So far, after about 4 full cycles of the batteries - I only recharge when below 10%), I'm getting about 5 hours on the 8-cell and 2.5 hours on the 4-cell. Note, that is with the WiFi on.

Really, that times are not that bad if you are coming from a lower class of laptop (well, they are all lower-class, right?). One reason for the high battery use anecdotally would be that Windows, esp. under Vista, is always doing something or other with the disk drive, every 10-15 seconds or so. I'm thinking of turning off indexing, but I'm sure there are other things like superfetch, etc., that are culprits, too.

One very nice thing is that in laptop mode, if you close the top the screen immediately goes off. That does help keep the machine going longer in big Internet iPod mode.

mgags7 · #4 Post by **mgags7** » Mon Jul 16, 2007 12:32 am

bahaha big internet ipod mode.

I can see myself now doing homework at a table on campus somewhere rockin out. lol

superfetch definitely eats up some power. I'm almost curious enough to install xp pro on my usb hard drive just to see what kinda life it would get on the bare os. I bet it could do something like 8 full hours.

SFWrtr · #5 Post by **SFWrtr** » Mon Jul 16, 2007 11:01 am

There's nothing like Trance from Di.Fm or chill from Soma.Fm to make any work easier to do.

And that requires power. You either have to have the 802.11 or the MC5725 on. Remember, I get about 5 hours with 802.11 on.

Still, XP will probably give you better times, but probably not all that better. XP non-tablet edition still does all sorts of stupid background stuff and it does have an earlier attempt at superfetch. I have turned off indexing, but that helps only a little. I don't think that my hard drive ever really powers down as something its it every 15 seconds or so.

[RAVE]And that is the point, Microsoft! You need to design a battery mode for use on notebooks. [/RAVE]

Realistically, if you don't power down everything and are willing to use the lowest screen brightness, you are not going to get the 7.5 hours that the 8-cell is rated at. If you set your screen black-out timeout, use max battery, put it in standby when not at use, be disciplined about turning off the radio switch, and use just the brightness of screen that is necessary while you are using the machine, you can probably get about another hour out of it.

Then again, you could probably get a 4-cell and use it as emergency power - or just plug in.

IMHO, 5 hours is pretty darn sweet.

ctrler · #6 Post by **ctrler** » Mon Jul 16, 2007 2:27 pm

Are you using USB? USB consumes a lot of power.

SFWrtr · #7 Post by **SFWrtr** » Mon Jul 16, 2007 3:05 pm

ctrler wrote:Are you using USB? USB consumes a lot of power.

Rarely. I download pictures from the CF card and immediately disconnect the unit. Most of the power is consumed by the screen and by the wireless. I do not use the SD slot or the card slot.

xaveon · #8 Post by **xaveon** » Mon Jul 16, 2007 10:25 pm

This is my battery information:

Full charge capacity: 72.63 Wh
Current: 1.25A
Voltage: 14.62 V
Wattage: 18.29 W
Temperature: 35 C
Cycle count: 32

Is the battery meter accurate??? Currently my battery is at 75% and it's showing that I have 2:22 hrs left. I don't think I have ever seen 5hr +.

xaveon · #9 Post by **xaveon** » Mon Jul 16, 2007 10:30 pm

hmm... Why are my numbers so high compared to yours? My wattage is 18 compared to your 10. Is anybody else getting these numbers?

Kenn · #10 Post by **Kenn** » Tue Jul 17, 2007 11:26 am

There doesn't happen to be a way to toggle off the tablet features is there? I don't know how much power it draws, but it wouldn't seem to be trivial. Just seems like sometimes you just don't need the pen input for long periods of time (surfing, word processing, etc.).

Also, I imagine there are at least a couple of us considering the x61t for the sole benefit of SXGA+ on a 12" w/ outdoor-viewability, and don't really need the table features day to day.

SHoTTa35 · #11 Post by **SHoTTa35** » Tue Jul 17, 2007 12:14 pm

xaveon wrote:hmm... Why are my numbers so high compared to yours? My wattage is 18 compared to your 10. Is anybody else getting these numbers?

Wattage is based on current usage. So if you have your wifi on, have the brightness up to full and using the CPU at full power vs speedstepped down to 700mhz or something you will use more power. The power options profiles controls what the CPU does. So if you leave it on portable/laptop or "balanced" if you're using Vista then you'll get more battery life.

And for everyone else, when posting the battery numbers post your design capacity and the full charge capacity (as well as the other info) since that's the most important part. We know the 8 cell holds x amount but if your full charge is only 50% of that then having an 8 cell wont get you 5hrs still.

xaveon · #12 Post by **xaveon** » Tue Jul 17, 2007 12:32 pm

My design capacity is 66.24 Wh. Does that mean anything? Is there a reason why it's lower than the full charge capacity?

SFWrtr · #13 Post by **SFWrtr** » Tue Jul 17, 2007 12:36 pm

Kenn wrote:There doesn't happen to be a way to toggle off the tablet features is there? I don't know how much power it draws, but it wouldn't seem to be trivial..

Not that I have seen.

I think the reason is that the tablet subsystem will draw some power, but it probably is trivial. If I understand correctly, the pen contains a battery and it is the action of the pen that generates the signal. Contact with the surface of the screen, in addition to the hover behavior, actuates a rheostat or something similar, sending a signal of 1-256 levels of pressure. I'm not sure if this is capacitance or inductance, but there the screen probably does have to be charged up. Still, it is probably not discharging greatly until the pen hovers or makes contact As for the touch part, this is probably again something that requires a charge, but works more like a switch when you press the screen.

I'm sure there are more technically minded people out there, and I am sure there are actual specs about this that somebody can post. Still, I am pretty sure that the amount of energy needed to run the pen/touch feature is pretty trivial. More trivial than the Santa Rosa trick that actually controls the flexing of the LCD crystals, halving the rate from 30/sec to 15/sec when the system or video is idle, saving just a trickle of juice.

SFWrtr · #14 Post by **SFWrtr** » Tue Jul 17, 2007 12:41 pm

xaveon wrote:My design capacity is 66.24 Wh. Does that mean anything? Is there a reason why it's lower than the full charge capacity?

You have a marginally better battery than the design spec embedded in the battery's ROM. That's a good thing.

rog1039 · #15 Post by **rog1039** » Fri Jul 20, 2007 3:52 pm

FYI: There is no battery in the pen.
Paul

SFWrtr · #16 Post by **SFWrtr** » Fri Jul 20, 2007 4:44 pm

rog1039 wrote:FYI: There is no battery in the pen.
Paul

You are correct. My old tablet (you know, digitizer pad) pen still works just fine on the X61, and it has a battery. But, like everything else, the technology has changed.

Wacom says: "No battery in pen. Patented battery-free technology allows pen to be powered by the tablet. It is maintenance-free and never needs charging. "

From the penenabled page: http://www.wacom.com/tabletpc/what_is_penabled.cfm

This means that the machine is generating a field that the pen can use for power, I think, though inductance. If that's true, then there is some amount of power going to the equipment to run the interface.

Comage · #17 Post by **Comage** » Fri Jul 20, 2007 10:16 pm

Not sure if your model has infra-red on it, but disable it (turn it off) under Device Manager if you don't use it often. It maybe give you 30 minutes more or so.

sugo · #18 Post by **sugo** » Sat Jul 21, 2007 12:08 am

At least in my experience, turning off infra-red doesn't make any noticeable difference in power consumption on both X60s and T42. I used mobile monitor for watching wattage.

xaveon · #19 Post by **xaveon** » Sat Jul 21, 2007 12:12 am

I'm pretty sure I have infrared but I can't seem to find it under control panel. Do you know what it's called under control panel?

#20 Post by **JaneL** » Sat Jul 21, 2007 7:47 am

xaveon wrote:I'm pretty sure I have infrared

According to the HMM and tabook, infrared isn't available on the X61 Tablet.

#21 Post by **tomh009** » Sat Jul 21, 2007 12:35 pm

X61, T61 and R61 no longer have infrared. The sensor plastics may still be there, but the electronics are not.

SFWrtr · #22 Post by **SFWrtr** » Sat Jul 21, 2007 4:45 pm

Re: Infrared
Checking device manager confirms there are no drivers installed, however, there is what amounts to a big typo here where it says there is an infrared port:
http://www-307.ibm.com/pc/support/site. ... MIGR-68041

For those interested in battery specs, I now have both of mine fully charged so here's what I see. Note that in both cases I am getting better than design specs in the field. Note that this is my cycle-count at 1 month of having the machine. The temperature sensor is rather interesting; what's up with that?

8-cell:
Remaining percentage 100%
Remaining capacity: 72.35Wh
Full-charge capacity: 72.82Wh
Voltage: 16.52V
Temp: 30C
Cycle Count: 5
Manufacturer SANYO
Manufacture date: 207-05-24
First used date: 2007-06
FRU 93P5032
Chem: Li-Ion
Design capacity: 66.24 Wh
Design voltage 14.40V

4-cell:
Remaining percentage 100%
Remaining capacity: 31.48Wh
Full-charge capacity: 31.64Wh
Voltage: 16.60V
Temp: 26C
Cycle Count: 7
Manufacturer SANYO
Manufacture date: 207-04-06
First used date: 2007-06
FRU 42T5250
Chem: Li-Ion
Design capacity: 28.80 Wh
Design voltage 14.40V

#23 Post by **tomh009** » Sat Jul 21, 2007 10:23 pm

xaveon wrote:hmm... Why are my numbers so high compared to yours? My wattage is 18 compared to your 10. Is anybody else getting these numbers?

18W is very high -- I would expect numbers in the 10W range. My current X31 (1.4 GHz Pentium-M, 1.3 GB RAM) can run at about 8W with wireless still on.

What was your system doing when you took those measurements? What power profile?

Realistic Battery Times for X61t

Realistic Battery Times for X61t

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