How much of a better are the 'upgraded' batteries you can get when you buy a laptop?

[mynameis]

The Compaq V2000 has the option for a 12 cell battery over the standard 6 cell for only $40. The Dell Inspiron 6000 has a similar option for 9 cell over 6 cell for $80.

Anyone have experience with exactly how much better battery life you get with the upgraded battery? I assume double the cells doesn't exactly mean double the battery life, am I wrong?

[Hammerstein]

You've got that right. Batteries are measured in a unit called mAh (aka Milli-amp hours). This is a very odd unit, to say the least. Basically, it's expressed this way so you can calculate two things -

1) how much amperage you can drain per hour if you'd like to get x hours of battery life. Say I want 3 hours of battery life on a 2100 mAh battery. Then

2100 mA * hours / 3 hours = 700 mA. In other words, I can draw 700 mA continuously, if I'd like to have my battery last 3 hours.

2) how much battery life you get for drawing a certain amperage. Say again a 2100 mAh battery, but I'm drawing 70 mA continuously. Then

2100 mA * hours / 70 mA = 30 hours

So my battery will last about 30 hours.

But, basically, what all of this is telling you is to ignore the number of cells on your battery and look at the mAh rating. A 6 cell battery will not have half the mAh of a 9 or 12 cell, but the battery with more cells should have more, definitely. If it's not significantly more, then the "high capacity" battery is a rip off I'd say.

Keep in mind, though, that a 12 cell will also possibly weigh more. Be sure you know if there will be any weight or size penalty by upgrading. For example, on the IBM T-series, the 9 cell battery sticks out of the back and adds like .25-.5 lbs of weight compared to the 6 cell, which sits flush on the laptop. Those are other important considerations.

[mynameis]

Thanks for explaining that to me.

The 6-cell battery for the V2000 is 4400mAh while the 12-cell is 8800mAh, easily worth the extra $40 I am guessing, it sucks that you have to special order and wait 2 weeks to get it though.

[kpxgq]

its worth it... the standard 4-cell battery that came with my 700m gave me about 2-3hrs.... with the 8-cell battery i got 5-6 hours

[Chuck232]

Thanks for explaining that to me.

The 6-cell battery for the V2000 is 4400mAh while the 12-cell is 8800mAh, easily worth the extra $40 I am guessing, it sucks that you have to special order and wait 2 weeks to get it though.

Be aware that the 12 cell will stick out the bottom quite a bit. But yeah, you get about 5.5 hours with the 12 cell compared to 3 or so with the 6 cell.

[mynameis]

Be aware that the 12 cell will stick out the bottom quite a bit. But yeah, you get about 5.5 hours with the 12 cell compared to 3 or so with the 6 cell.

I'll keep that in mind.

I wish Compaq would provide better pictures and specs on their website. I couldn't find info about the batteries there and I would be interested in seeing the size difference in batteries.

[sharkyfel]

Wow. I think I will upgrade to a larger battery. 3 hours and dead is killing my productivity :)

[mynameis]

Wow. I think I will upgrade to a larger battery. 3 hours and dead is killing my productivity :)

If don't buy them with the laptop then it'll probably end up costing $100+