battery care ?

[awallin]

Hi, just ordered a T60 (UT063, 14"/1gb/100gb) and found this great forum.

I read on some site that LiIon batteries should never be discharged completely, and that it's best to remove the battery when hooked up to AC mains.

I _don't_ want to remove the battery everytime I plug in the machine at work (for maybe 6-8h at a time)

please, please tell me the T60 charging circuit is smart enough to do these things on its own ?

[marlinspike]

People are just worryworts. The only thing I would do is when you get it, double click on the green battery icon in the taskbar, click the battery information tab, click battery maintenance, and then select optimize for battery lifespan.

[matman]

This quote from the battery information tool is good advice.

If you primarily use your computer with the ac adapter attached and only infrequently use battery power, battery deterioration may occur faster if the battery is constantly charged at 100%. Lowering the charge thresholds for your battery and periodically resetting the battery gauge will help increase its lifespan.

You can't reasonably expect the battery to have useful capacity after about 3 years. Li-Ion cells deteriorate over 2 or 3 years no matter how they are used, even if they are not used. That said, there are some conditions that will wear on the battery more than normal. Both 0% and 100% charge levels are harder on the battery than 40% charge. The optimum storage or maintenance charge level for Li-Ion cells is 40-ish%. You can use the Alarms function on the Global Power Settings tab to avoid hitting 0% and custom set maximum charge level in the battery maintenance window to stop short of 100%. Of course the trade off is less battery time before you need to recharge.

What settings you use depends on how you use the machine and how important battery longevity is to you, not just how long you need between recharges but also the average power load. For me, the train ride to work takes about 40 minutes. With reckless use of power settings and Company of Heroes I can empty the battery completely in that time. Unfortunately my train trips are most often spent reviewing email which typically uses more like 30% capacity over 40 minutes. I could set my min-max to 25%-75% and be all set for email but might run out of juice before finishing a game level if for some reason my inbox is empty. Since it is supplied by my company and I switch to a new model at least once a year I really don’t care about battery performance down the road so I leave it at 5%-100%.

Ahh geez. I've been rambling again. To answer your question, the T60 has sensible defaults that give you close to full battery capacity without hammering either extreme of the charge cycle.

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

[Hanson]

I have a T43 and I only let it charge upto 90% of capacity for the past 35 cycles between Mid-September to now. During this time, I have lost only 40mWh from 46580mWh to 46540mWh. This is miniscule compared to charging to full capacity and losing 5000mWh from 20 cycles since the battery was first used last November (exactly one year today). The capacity was 51.83Wh.

Based on that experience, I would recommend that you avoid charging upto 100% unless absolutely necessary.

[uberT]

Guys, I assume there's no facility for setting these charge thresholds on an older machine like my T30. I see the option on our R60 and the T43.

I'm also going to assume that the later versions of Power Manager are not compatible with my older T30.

Thanks.