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11 Posts

02-23-2010

Az

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Reduced Performance When No Battery

2010-03-13, 10:29 AM

I've noticed something on my T510 that's interesting and also a little disturbing. If I run the T510 off the power adapter, without the battery, the clock frequency never goes over 50% (according to the Win7 Resource Monitor) even though both processor cores are at 100% load (I am using LinX to load the processor). The CPU temp is only 42c so it's not a temperature issue. I have the power options set for max performance. If I put the battery in, the max frequency immediately goes to 110% (Turbo Boost), so this behavior seems to be a power issue.  I guess it is by design, the battery is used as secondary power source when extra power is needed, if the battery is not there than the clock stays low. This is a little disturbing though, because it means  that I have to leave the battery in  the laptop - not the best thing for the battery life.

The T510 comes with two different power adapters, a 65w and a 90w. I have the 65w. I wonder if there would be a change in this behavior if I got the 90w adapter. I would really appreciate it if somebody with the 90w adapter would run a test (take out battery, load cpu, and check clock freq with Resource Monitor) and let us know the result. TIA!

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4096 Posts

01-05-2008

DE

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Re: Reduced Performance When No Battery

2010-03-13, 11:30 AM

Hello Myron999,

 

that is totally normal and your ThinkPad is working as designed.

 

The best thing you can do with a battery is to use it, if you´re plugged in, then the Lenovo Powermanger will do all for you regarding the battery health.

 

So stick your battery in and enjoy your system running at full performance, if needed.

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11 Posts

02-23-2010

Az

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Re: Reduced Performance When No Battery

2010-03-13, 19:30 PM

@ 

 

Do you know if the T510 will operate at full speed without the battery if I use the 90w power adapter?

 

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69 Posts

07-31-2009

Hudson Valley

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  • Message 4 of 8

Re: Reduced Performance When No Battery

2010-03-14, 0:54 AM

If you are concerned about reducing the battery life by always using the machine on AC power (with battery installed) note that you can use the Lenovo Power Manager utility 'Battery Maintenance' feature to set charge thresholds so that the battery can be maintained at practically any charge level you want while on AC power.  I've read that Li Ion batteries should be stored at around 40% of full charge; since my laptop is almost always on AC power I set the charge thresholds to stop charging at 40% and begin charging when the level drops to 35%.  There is also a 'maximize battery lifespan' setting though I'm not clear on what charge threholds that will set.

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11 Posts

02-23-2010

Az

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Re: Reduced Performance When No Battery

2010-03-14, 4:47 AM

Thanks Burd, yes that is a useful function. However, you can do much better by charging the battery to 40% and then storing it in the fridge.

 

a) A Li-Ion battery kept at 40c and 40% charge losses 15% capacity in one year.

b) A Li-Ion battery kept at 0c and 100% charge losses 6% capacity in one year.

c) A Li-Ion battery kept at 0c and 40% charge losses 2% capacity in one year.

 

(a) vs (b) is interesting from an academic perspective, but the real world choice is between (a) and (c). To me that's a pretty significant difference.

 

http://www.batteryuniversity.com/parttwo-34.htm

 

 

 

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11 Posts

02-23-2010

Az

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Re: Reduced Performance When No Battery

2010-03-14, 4:52 AM

forgot the worst synario:

 

d) A Li-Ion battery kept at 40c and 100% charge losses 35% (!) capacity in one year.

 

So clearly the option to maintain the battery at 40% IS a useful function.

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213 Posts

12-06-2007

US

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Re: Reduced Performance When No Battery

2010-03-16, 16:56 PM

According to battery university, if you store your pack at room temp (25c, 40% charge) you only degrade 4%, and if you store it at 0c you degrade 2%. Personally I recommend room temp and would stay away from putting your battery at freezing temps. However if you do, you should let your battery acclimate to room temperature for 24 hours before you use it. This will let the fluids within the cells return to their optimal state.

 

One other point is you cannot store you battery long term without periodic charging. Li-ion cells will self discharge. So your 40% will drain to 0% or below if left sitting on a shelf long enough. I recommend you take your packs in storage and charge them back up to 40% once every 3 months.

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382 Posts

02-13-2009

US

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  • Message 8 of 8

Re: Reduced Performance When No Battery

2010-03-16, 23:35 PM

I have a T500 which has had it's battery installed for over a year and it still retains 98% of its rated power, this is after a year sitting in the laptop, charging set to default other then "extend battery life" checked in power manager and the laptop is most often run off AC power.  The few times that it has run down I never let it discharge below 20% (which gives me about a 6hour battery life on the 9 cell with my DC power scheme in vista..)...

 

Sure it would be nice for the battery to last forever, however I would much rather be able to use it on demand.

Thinkpad T500-2081 CTO | T9400 2.53GHz | 8 GB RAM | ATI HD3650 + Intel GM45 | 15.4" LED WXGA+ | Windows 10 | ATI Catalyst 13.1 (non-switchable)
Thinkpad 390x | PII 333 | 256mb ram | NeoMagic 256AV | SVGA LCD | OS/2 v4.52
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