real-world T420 / T420s battery life ?

Greetings -

Can anyone advise what T420 (or T420s) 6-cell battery life is
with wireless networking OFF and screen at half brightness?
(i.e.- Just used for day of classroom notetaking?)

Thanks kindly,

- Richard

 

If you have to ask that question, you should get the 9 cell. No ifs, ands or buts. Remember that battery performance degrades over time.

You may not like the way the 9 cell juts out, am I right? I used to be the same way. You will get used to it, and in the end may even like it.

FWIW, based on my 9-cell performance, on the 6-cell you'll probably hit about 5.5 hours on brightness 8 without a lot of other stuff running in the background, wireless off, and the laptop set to maximize battery lifetime (i.e. not charge all the way to 100%, which can shorten your battery life).

 

Or, possibly, the bay battery?
(Correct, I REALLY don't like that hump sticking out the back. )

 

The T420s has a bay battery capability, but sadly the T420 lacks that ability. The electrical connection isn't present in the bay. Instead they went with the "slice" battery approach; I think this was boneheaded personally, since the two didn't need to be mutually exclusive. I think the lack of a correctly implemented bay battery on the T420 is one of its biggest design failings. (The other two biggies, for me, are the lack of any 16:10 screen options, and the rough-textured, non-inset touchpad.)

Even if you were to get a T420s, you'd find that the battery life wasn't as good as the T420 with the same number of cells in the battery, mostly because the batteries are physically smaller. You'd wind up getting a bay battery, maybe, but increasing the weight until you might as well have bought a T420-- and the bay battery is implemented in a subpar way, where it discharges to 0% by design each time before the main battery is used, resulting in terrible battery life due to the constant full discharges.

All I can say about the nine cell is that I've been there-- I HATED the bulge. But now, on the T420, it's the smallest it's ever been, and I promise you will not even notice it after using the laptop for approximately a month at most. I promise. I really think that if you're a student, you will do yourself a huge favor by buying the nine cell.

From a purely design standpoint, you can appreciate the battery jutting out the back if you realize that the other main approach would be to make it bulge out of the bottom. Lots of laptop designers do this. That approach makes the laptop thicker and hence harder to shove in a bookbag or case.

The thing I used to hate the most about the battery bulge was the fact that it was off-centered. Honestly, if I were designing a laptop like the T420 I would probably have moved all the ports from the back of the laptop, just to allow an extended battery that covered the entire rear of the laptop but could have jutted out less far because of that. {shrug} They don't pay be to design laptops, so I just spout off at random here.

ETA: I just wanted to mention that my 5.5 hour estimate is for the six cell. I wasn't clear enough before.

 

Appreciate the feedback.

I've used a T60 (and a T42 or 43) with 'the hump' for work,
and endured it.

Must ponder ... .

Of course, I could always just buy a second 6-cell.
(Now *there's* something you can't do with a MacBook. )

Tho' the LaborDay price of the 9-cell is a not- too-painful $98 (~45% off).

 

At the moment I am running my T420s with both a main and bay battery. Last Saturday, when the mains power went off, Power Manager was predicting that I could run for 10 hours. I suspect that is an over-estimate but consider 8 hours to be achievable using both batteries, or 5 hours on main battery alone for your proposed operating conditions provided you make sure that no applications are running which cause significant CPU usage.

John

 

I get around 8 hours in the classroom with the T420 in my sig with a fully charged 9-cell.
With movies (usually netflix or a VLC 720p movie) around 4.5 hrs or so.