01-15-2010 03:37 PM
This problem is about to drive me insane.
It's new thinkpad X200 tablet and new 8-cell battery, only having 4 charge-cycle count.
I've just discoveried this problem when I upgraded to Windows 7 Pro and updated Power manager to V3.05 of my X200 tablet, but since it's on AC power most of time and I've set battery charging only starts when level below 5% and stop at 100%, therefore my battery only being recharged once or twice a week, but whenever it charges from 5%, it will just stop at 36% and display "charging will start when below 5%", so I will have to change the option in "battery maintaince" in Power manager to "alway fully charge" to have the battery 100% charged. But, I don't really want to choose the alway-fully-charge option torepeatly recharge the battery at near 100% since I have only a few occasion during the day where I need to rely solely on the battery, which only consume it down to ~90%.
I'm not sure whether the problem is due to the new version of power manager which regard my 8-cell battery as 4-cell?( logically, then it should stop at 50%, right?).
The battery once did charge on the ultrabase, but I can't remember if that was the time when the problem started.
Thinkpad X200 Tablet, 7450-AM7
SL9400(1.86GHz), 2GB RAM, 160GB 7200rpm HD, 12.1in 1280x800 LCD Touchscreen, Intel X4500HD, Intel 802.11agn wireless, WWAN upgradeable, Bluetooth, Modem, 1Gb Ethernet, Secure chip, Fingerprint reader, 8c Li-Ion
OS: Windows 7 Pro
Thinkpad Power Manager V3.05
Thinkpad Power Management Driver V1.55
01-21-2010 04:53 AM - edited 01-21-2010 04:56 AM
Unfortunately I have the same problem and always had. I have my x200t for about a year now and had several different versions of power manager and windows installed and it never worked. It always stops at about 35 % (can't quit remember). I already opened a post about this a little while back (http://forums.lenovo.com/t5/X-Series-Tablet-ThinkP
02-04-2010 03:19 AM - edited 02-04-2010 03:22 AM
happy to see someone having a look at this problem, thanks. I just checked my notebook again, and it stopped at exactly 36% every time I tried.
I can't speak for the others, but my reason for setting these thresholds is, that I'm at university all day long. During my lectures I take notes on my x200t, while running on battery and having everything set to minimum, but during my brakes I like to go surf the internet a little bit, turn up the brightness(looking at a dim screen all day is kinda stupid^^) and do other stuff. But surfing the internet of course, drains the batter pretty fast(and then it wouldn't last through my workday). So I always find my self a power outlet, set the threshold manually so that it doesn't charge and then surf the net(which is kinda annoying having to do this every time). When I get home in the evening, is set the threshold back to normal and fully charge my x200t.
I'm doing this, so that I can preserve my batterylife as long as possible. If I were to charge it every time that I want go on the internet, it would use up the battery's lifecycle much faster, than the way I'm doing it now. This feature was actually one of the main reason, why I decided to buy a thinkpad in the first place, so that I'd have a long lasting battery.
It would be very nice if you could find out what the problem is and how to fix it. Thanks again, for having a look at this problem,
02-04-2010 06:31 AM
I see your point. Your mid day surfing is on AC because you don't want to charge the battery during this time because it will consume cycles. There is another improvement you can make, let me explain.
First I need to define what 1 cycle means. As you know, within power manager you can view the current Cycle Count. This is the parameter which you are trying to minimize. The cycle count field is incremented when you have consumed an amount of energy approximately equal to the current Full Charge Capacity (also a field in Power Manager). This can happen in one full discharge event or in multiple smaller discharge events. For example, say during one day you use 80% of the total capacity. The effect on cycle count is the same if you had a continuous discharge from 100% to 20% (we’ll call this case A) compared with discharging a battery from 100% to 50% (-50%), then had time to charge it to up to 90%, and subsequently discharged back to 60% (-30%) (case B).
The real benefit of your method (Case A) versus Case B is case A results in a lower average state of charge throughout the day. Plus you’ve also placed an energy budget on yourself. Once you’ve discharged your battery pack, you are done (using the battery) for the day until you get home.
An alternative way to get similar results would be to set your custom charge thresholds to something like:
Start charging 80%
Stop Charging 85 or 90%
By not allowing the pack to fully charge and sit at 100% ever, you will minimize the degradation due to the length of time the battery was at full charge. This is another contributor to Li-ion capacity degradation. This setting would require you to do some mid day charging though if you were previously using all available capacity to get through the day when starting at 100%. The effect on cycle count will not increase assuming you don't use more capacity overall.
So I like your approach but to maximize the benefit maybe set your stop charging point to 85 or 90% if you can manage a little recharging throughout your day.
Back to the issue you reported, I checked with the team and they are working on a fix. I'll post back here when it is released.
02-04-2010 08:49 AM - edited 02-04-2010 09:38 AM
thanks for the advice! I'll try your version for awhile, till the fix is out.
03-10-2010 11:15 PM
I have installed the update but haven't had time to test it yet. I'll tell you if everything works all right by the end of this week.
Thanks again for all your efforts and for looking into this problem!!!
03-16-2010 04:16 AM - edited 03-17-2010 01:16 AM
Ok, so I have been charging my x200t a couple of times and it seems to be working perfectly, always 100%. So, once again, thank you very much Ken for all of your efforts and for helping us with our problem!!!