T420s vs T420: Why the drop in estimated battery life?

Why is there a huge drop in the estimated battery life of the T420s vs the T420 when both have 6cell batteries and the same specs?

 

Look at the energy capacity of both batteries.

 

Same specs? No.

A 6-cell battery (44Wh) cannot the same as another 6-cell battery (57Wh), no matter how cute it is. A weak 6-cell battery plus a puny 3-cell battery (that gets drained all the time) do not perform as well as a stronger 9-cell battery (94Wh). Also, cell size does matter.

I wish Lenovo called the T420s by some other monicker to avoid all sorts of confusion. Why not X420 or whatever? (Aha. Now, we will demand IPS and slice battery!) On the other hand, there are no significant reasons (other than causing confusion) for designating the W520 by "W": why not just T520, or maybe T520p? On the same subject, why the need for T420i when it is just a CPU option?

Nuts.

 

Look at the watt hour ratings on the batteries. I remember HP charging extra for a lower WH battery on their 8530 and stated that it was better or greener or something. I was perplexed at their claim, but for this scenario it has to do with thickness as the t420s is thinner and cannot pack the same sized cells. Same basic idea with the 9 cell on my x200s vs the one on my t400.

 

The T4xxs series uses lithium polymer batteries that do not hold as much charge as the more traditional T4xx's batteries, hence the lower Wh capacities. This is largely due to size constraints present in the thinner T4xxs series.

As far as I know, though, the X200s and T400 9-cell batteries have the same capacity, as both take up roughly the same amount of space.

 

I remember reading this when looking for my thinkpad. I cannot compare my thinkpads as the x200s had a terrible first owner and is at 66% capacity. But I am pretty sure the t400 had a higher capacity 9 cell vs the x200s.