Changing the battery - while laptop is turned on.

[Passa]

Hi guys,

I have two batteries for my R50 - a 6-cell that only holds a charge that lasts for 20-30 minutes, and a 9-cell that still holds 90% of it's capacity (lasts up to 7-8 hours).

Naturally I switch between them every often. I have a spare charger on the kitchen counter so I can just pop down there with the 6-cell since it's enough to keep the laptop alive while I plug it back in. I use the 9-cell when going somewhere out/working outside/on the couch etc.

I never turn off my laptop (current uptime would be nearing 40 days I imagine), so when I swap the batteries, I do it when it is turned on. By now, I've probably done this hundreds of times and never had a problem.

While mentioning this practice to a laptop-nerd friend, he went crazy and said my batteries should have exploded by now. He said the one time he did it on a T43, the thing exploded and the motherboard shorted.

What is the correct practice regarding this? I know Lenovo/IBM manuals maintain you should shut it off and unplug it before changing batteries.. but yeah.

[rkawakami]

Correct practice = what the manual says. I suppose that there is a tiny possibility of shorting out the battery contacts or generatng a spark which might ignite some flammable gas nearby or causing a power surge in the laptop due to the sudden influx of current when the battery is snapped in. That said, I've also swapped out the battery from T2x and 600 systems while they are plugged into the AC adapter more times than I can count and I'm still around to type about it (and so are all of the systems and batteries).

[sjthinkpader]

....
I never turn off my laptop (current uptime would be nearing 40 days I imagine), so when I swap the batteries, I do it when it is turned on. By now, I've probably done this hundreds of times and never had a problem.
...

I also change battery while A/C is plugged in.

BTW, I hope you use the Power Manager to turn off the LCD and HDD. These components have somewhat limited life.

[hausman]

Me too with several generations of ThinkPads and never had a problem. In fact until I read a warning against doing it a couple of years ago I didn't even know there were any potential problems.

[sjthinkpader]

There were some problem especially in A2x generation booting without the battery in place. The voltages are not as stable and BIOS writes can corrupt the BIOS Flash and cause a CRC failure.

But once the computer is booted, there should be little risks.

[Passa]

BTW, I hope you use the Power Manager to turn off the LCD and HDD. These components have somewhat limited life.

LCD shuts off after 10 minutes (and I keep the lid down anyway). HDD is only a few weeks old now (the laptop's 3rd drive, I've continuously upgraded it) so that isn't a big deal. And I was of the belief that it is better for a drive to keep spinning than constantly spinning up and down.

Anyways I'll keep doing it then. Hopefully it's just a ThinkPad feature, will be getting a new ThinkPad at the end of the year and it'd be a pretty big deal-breaker if I couldn't swap batteries while the thing is on.

[seaweedsl]

Do you know that a battery is supposed to wear out quicker installed in the machine than out - due to heat?

Also, constantly topping off a stored battery will give you maximum run time when you need it, but you'll also be slightly using up your charge capacity each time you top it off. It will store better with a lower charge.

I suppose the best strategy is to keep the nearly dead battery in the machine all the time and just top off the 9-cell right before you need to use it - if you think you will need full charge.

Steve