Help with toshiba litium Ion battery

[jk323]

so I bought a toshiba budget laptop. Everything spec'd came on a budget including the battery, it is 14.4V x 2000 mAh 4cell and lasts about 1.25 hours in normal operation which is very low.
So Im in the market for a new battery, however toshiba has two different types.
one is:Capacity: 14.4V x 4300 mAh with 8 cells
other
is: Capacity: 10.8V x 4000 mAh with 6 cells
however toshiba says the 6 cell one will last 30 more mins than the 8 cell, how is that possible, I thought mAh was total capacity..
so Im debating on which on to get, the 8 cell costs about 50 bucks more as well. But money is not an issue, I want to get the longer lasting one without needing to buy both.
My original battery came with 14.4 v but toshiba says both will work so running 10.8v is fine?
can anyone tell me which one would last longer?
is it the 10v one that will last longer since it consumes less energy?

[SeanC]

I'm not an electrical expert but I think the reason they say the second battery will last longer is because it puts out less voltage which means less power being sucked from the battery cells compared to the first one.

Sean

[jk323]

yeah thats what i thought too.

[DanU]

Voltage by itself, or current capacity by itself, is really irrelevant since all laptops have a built-in DC-DC converter to up/down convert the battery's voltage to whatever voltages are needed by the actual laptop's circuits. The battery's voltage itself isn't steady. A lithium ion cell will start at about 4.2V fully charged and then drop to about 3.0V when fully exhausted.

What does matter is energy. The 8 cell battery can store 61.92 W*h of energy. The 6 cell battery stores 43.2 W*h of energy. This means the 8-cell battery should last almost 50% longer than the 6 cell battery.

Do you have links to the batteries you mentioned above?

[jk323]

http://www.toshibadirect.com/td/b2c/...HO&poid=298787
8 cell
http://www.toshibadirect.com/td/b2c/...HO&poid=306454
6cell

[jk323]

so which one do you think will last longer? toshiba supposedly says the 6 cel would last 30 mins longer, but odd that they sell the 8 cell for more..

[DanU]

Yeah, very odd. The runtimes come from a "MobileMark" test. But no links are given to the actual test. Maybe the 8 cell battery was tested in a powerful workstation class laptop while the 6 cell was tested in a less powerful one. One thing is for sure, assuming an equal load, the 8 cell battery will last 50% longer than the 6 cell battery.

As Scotty used to say, "Yae cannae break the laws o' physics, Captain."

[jk323]

well I got the 6 cell battery, I think the 6 cell will last longer due to less volts it takes or so toshiba says.