Question to all T400 owners

- How much battery life do you have left with 6 cell?
- what operating system are you using?
- How long have you add your laptop for?

I've had my T400 for about 9 months now, and switched to Windows about a month ago, and my battery dropped to like <4 hours minutes. I was able to get up to 5 hours and 40 minutes

 

O_O

On a six cell?

My T400 pulls 3.5 hours at moderate brightness, wifi on, switchable on integrated... Always has...

I'm running Windows 7 x64, P8700 undervolted with RMClock.

(I do have a slight feeling my drivers are messed up because I'm pulling around 18 watts on idle.)

 

Note that there's a bug with the switchable graphics drivers in Windows 7 - when resuming from sleep/hibernate, both the integrated and discrete GPUs are active and consuming power. You have to toggle to discrete and back to integrated to revert to integrated-only. That might be what's causing your increased power consumption.

 

I've seen those conditions; TPFanControl starts reporting GPU temperatures even though the Power Manager tells me I'm on integrated. Under those conditions, it starts reporting wattages in the 25+ area.

 

T400 with 6 cell just under 4 hours with brightness on 70% or so ... maybe more like 3:45. Never 5 hours no way. Had it for 4 months.

 

Yeah... 3:45 sounds about right for a six-cell. I do notice that I can usually squeeze out a bit more battery time (maybe 20 minutes?) by running "net stop uxsms", which turns off Aero.

 

Oh yea, I forgot to mention, I was able to get 5 hours and 40 minutes on Vista running on integrated graphics.

Windows 7 is a completely different story. Even disabling discrete graphics in bios, I can probably get a maximum of about 4 hours

 

On my configuration, with integrated graphics only active, Power Manager reports 8watt at idle with brightness ~12 of 15 bars, wifi on, optical drive off. With the ATi on, power goes to 10-11w. I have never tried one of these outlet watt meters. Would really like to see how it compares to the Power Manager's readings. Theoretically on my 4 cell battery I should be getting 4.5h battery at idle (37w / 8w/h ~= 4.5h). I can easily get 4h if I lock the frequency down for programming and/or writing in Word.

I use HWmonitor (free from cpuid.com) to get the full charge capacity to compare with designated capacity. Maybe your battery has decreased in capacity enough already to make a difference. I have my thresholds at 35 to 45% and use a cooling pad to lower battery temp. I hope this is helping prolong life and decrease capacity loss.

I just don't understand how could someone get <4h on a 6cell. I have aero and all other eye-candy disabled and run very few background processes. Maybe that's part of it. Even on Adaptive CPU policy I get > 3h...

 

I never used the Vista preload; I wiped it ASAP and dumped Windows 7 on it.

Are you getting 8W on minimum brightness? I'm getting around 13W with 0 brightness, wifi on, fan off, and CPU locked to minimum, although the discrepancy could be my 5400RPM drive, which seems never to be parked no matter how long I leave it.

And my battery is at the design capacity at the moment (it used to be 3 Wh higher than design) so I don't think battery degradation is significant...

 

No, as I wrote this is with 12 out of 15 bars (displayed on screen) brightness. I have a solid state disk and a LED-backlit screen and specifically ordered no Bluetooth nor web camera to reduce battery consumption - maybe this is the difference?

I hardly ever hear the fan kicking in. I had a theory that a faster CPU can actually use less energy as it does things faster and while it uses more energy while at 100%, it finishes the work faster and does not heat-up that much and the fan don't kick-in. So for normal, not very heavy usage, total energy consumption may be lower because of no need to turn on the fan.

Wish I had a watt meter to test the Power Manager readings...

BTW my battery was always the exact same full charge capacity as the designated capacity (37.44 Wh) . I see the 9-cell refurbished battery is ~40 at the lenovo outlet right now...

@pk_volt - what size is your battery again?

 

faster fan does not equal energy saving.

Since the geometry of the fan is set, so a fan running at twice as fast does not mean it would move twice as more air through the heatsink.

The perfect balance of rpm and battery saving is probably not set at the maximum rpm, usually it would be within 2000 rpm range.

 

I have a 6 cell.

As mentioned, I had windows vista installed on it and I got like 5 hours and 40 minutes with integrated graphics with wifi on etc etc.

Does windows 7 draw up that much more power?

 

Possibly with all the extras. I tend to measure battery life out of box as in I cannot be bothered having brightness to low etc still needs to be comfortable.

 

In a lecture environment, just browsing the class webpage and ppt presentations (so no flash), wifi on, integrated gfx only, LED screen set at 50%, P8400, and RMClock running on Vista Ultimate x64, I've seen it report 6hrs 47min on a 6-cell.

But, realistically, I can expect about 4.5 hrs from the 6-cell with wifi on and typical browsing at 80% screen brightness. Planning to experiment with Win7. XP had shown to shorten battery life by 30min-1hr.

 

On Win 7 Pro (R400), with similar operating conditions (particularly wifi on but bluetooth off) as you describe, I get about 4 hrs 45 mins or so. But my machine is very new - maybe that plays a role.

 

A better question is what is the design and actual charge of your battery?

and how many cycles have your battery clocked up?

You can find these information under Thinkvantage Power Manager battery information.

 

Ach... Still pushing around 4 hours max on a 6-cell here. Tried disabling a whole bunch of devices in bios (Bluetooth, WiMAX, WWAN, and a bunch of stuff I don't even have), to no avail.

My battery is a Panasonic 6-cell with 56.22Wh capacity; and has gone through 110 cycles.

Is it possible that having the WXGA+ screen, albeit LED, can account for that much power consumption? Also, did you guys also order the Intel Turbo Memory? Could it be that the cache device consumes more power than it saves (if any)?

 

turbo memory not really suppose to save energy, it is there to boost performance.

 

Just installed Win7 Pro x64. Glad to report battery life hasn't changed much compared to Vista Ultimate x64. Perhaps there's a very slight increase but, more importantly, at least it didn't go south like others experienced after going to Seven. I don't have switchable graphics, though. Interestingly, Power Manager and RMclock report different "time remaining". RMclock seems to update quicker, too.

I remember past version of Power Manager allowed you to adjust the update interval. Maybe I'm wrong or is that feature absent in the current version of PM?

Doesn't seem like RMclock made much of an improvement to temps or battery life as it did on Vista. Should credit go to Win7's better native power management features? I do like the changes in Seven and apps feel more responsive, but nothing overwhelming.

 

I've gone thorugh 117 cycles

design capacity is 56.16 Wh and full charge is now at 46.60 Wh

I get a max of 4 hours with windows 7 running on battery optimized mode on integrated graphics with wifi