t520 battery goes from 50% to 4% in the blink of an eye

hey!

weird thing happening with my t520 battery: it goes from 50% to 4% in the blink of an eye a lot of the time when unplugged.

any thoughts on why?

i've had the machine for about two years, and it's stayed plugged in most of the time around 94% using the power manager.

is this a problem with the battery -- or could it be a software thing?

also, if it's a problem with the battery, how much does one usually run?

thanks!!!

 

That's a blown cell - or two - right then and there.

Check whether your battery is covered under the recall:

Battery recall - Lenovo Support (US)

Good luck.

 

thanks!

i ran the checker and it said my battery isn't affected...so i guess i can't get another battery through this program

any other alternatives you may know of?

 

Yes, it needs to be recalibrated to its new (=lower) maximum charge. A simple guide here. Before you do that, however, first update the battery's firmware (check the readme too).

Battery firmware ... what the hell, next thing the vacuum cleaner needs a bios update .

In such a use scenario you really ought to have run a utility that keeps partial charge instead of the default 100% charge; it'd have a longer life span. Laptop manufacturers usually provide such software, but not sure Lenovo has one (can't find an option in Power Management that would do this). Anyway, that's par for the course.

After recalibration you're still looking at a not-so-good battery, so you could buy a new one or, for Fun & Profit, open the casing and solder in new cells. This requires soldering skills and care though; they still hold charge. Saves about half the cost of a complete battery with cells, casing and pcb. If you do buy a full set; note that there are different options to choose from concerning number of cells and capacity. The low-capacity (there's even a 4-cell ...) simply have fewer cells inside; when you open these up there's an empty space where extra cells could have been. Cost saving measure, of course; chances are your current one is a 6-cell/4400mAh and not the 9-cell/6600mAh that would've fit just as well.

 

don't kid yourself, I have had to update my Roomba vacuum a few times now.

 

I would say try the battery recalibration, but be warned, it can do more harm then good. I tried it on my old T410s 6 cell battery, and it actually wore out the battery more than it restored (it went from 37 WHr to like 35 WHr).

 

:laugh:

(buys broomstick)

 

^^^^^^

This.

I've killed quite a few "questionable" ThinkPad batteries by attempting to re-calibrate them with Power Manager. Obviously, YMMV.

 

Are you using battery thresholds?

 

thank you everyone for the help!

i'm going to try to recalibrate. if that doesn't work -- i'm likely going to buy a new one

i took a look at the ebay link up top -- any tips on how to make sure i order the correct one? a lot of these don't match my model # of 4239CTO

thanks!!

 

It doesn't matter: a T520 is a T520.

You can use any battery for T410/420, T510/520 and W510/520 just make sure that it's a genuine Lenovo battery and not a third-party one...

Good luck.