Battery power suddenly plunging

[boofoo]

I have an X60s that's about 18 months old and the battery has started acting strangely: at some point with just over an hour left (according to the Power Manager gauge), the bottom falls out, the machine suddenly thinks there are only 5 minutes left, beeps, and hibernates. This just started happening in the past week, so far as I've noticed. It goes with about 1:15 or 1:10 showing as the time left.

It's under Win XP SP2, on the extended 4-cell battery. Power Manager reports that the battery is healthy. I've done a reset with Power Manager, and that didn't help. I can't tell if it's overreporting how much power it has left, or part of the battery is damaged, or what. Any ideas?

[Harryc]

Unless you have another battery to test with, there's a 99% chance that your existing battery needs replacement, and a 1% chance that the charging circuitry on your system board is shot. Even at that, the charging circuitry usually works or it doesn't, not usually somewhere in between. Your choice

[boofoo]

Sorry to hear that but I guess that's how it goes. Is there any way to get the system to learn the battery's real capacity? I don't mind having only 3 hours instead of 4, but I do mind thinking I have an hour left and then having 5 minutes.

Also, I just noticed that Power Manager has gotten very confused about my battery's capacity. It got low, I'm charging it, and it seems to be stuck at 52%. But when I mouse over the gauge in the taskbar, it says "52%... 4 minutes to fully charge." That does not compute.
Update: for the past few minutes: 53%, 2 minutes to fully charge.

[tilneford]

Have you compared the XP battery guage with Power Manager? My experience is that even though Power Manager says there is so much time left, if the XP guage thinks the battery is empty, then XP shuts down.

Many say that running a lithium battery to a level below 15-20% will shorten battery life. This appears true from my experience.

[boofoo]

I'll keep an eye on that next time I run it on battery. But it is Power Manager that is giving me the warnings, not the OS, and PM does see the battery level as low.

One thought: this behavior is consistent with 25% of the power being missing--could one of the four cells have died or lost its oomph? Might that have this effect?

[iamdmc]

I don't think it's as simple as one cell spontaneously breaking down so much as it is a general degeneration in each cell of the battery. Considering you've used the battery for so long, this would appear to be the case.

Remember that batteries are a "consumable" product and will not last forever. Most batteries can handle a few hundred charge cycles before losing a lot of capacity, and a few hundred more until they're completely useless.

Good luck - try eBay for IBM/Lenovo-branded batteries (never use the non-OEMs). They can be a lot cheaper than the Lenovo store, and there are reputable sellers on eBay that won't screw you over.

GL

[boofoo]

Thanks for the info. The machine is owned by my employer, who will replace the battery for me.

The strange thing, to my mind, was the way the battery went. All the previous batteries I've had aged "gracefully": they slowly lost capacity, and the computer realized this and gave increasingly short forecasts of time remaining. In this case that doesn't seem to have been so; the battery just "went" and the computer doesn't seem able to keep up. Is that not unusual for Thinkpad batteries? The battery on my previous machine, a T42, aged quite gracefully, and reported declining capacity as it did so. But on this one Power Manage reports: a cycle count of only 93, a voltage ABOVE design voltage (16.51 vs 14.40), full capacity (37.44 Wh) and a condition of "good." Is that information really so unreliable?