Source: Tom's Guide US | Keywords: notebook, extended, battery | Themes: Laptops and Notebooks
7. Cell Technology
Older notebooks used nickel-metal hydride batteries (NiMH). Over the years manufacturers began replacing this design with lithium-ion (Li-ion) batteries, and now many manufacturers are moving on to lithium-polymer (Li-poly) batteries, such as the new 17” MacBook Pro from Apple.
Li-ion batteries are superior to NiMH because the more advanced chemistry offers better performance. The energy density of Li-ion cells are higher than that of NiMH, and Li-ion cells exhibit relatively low self-discharge at 5% rates compared to NiMH's 30% rate. Li-ion batteries also don’t suffer from memory effect (memory effect occurs in NiMH batteries when they lose their ability to hold a full charge over time, and only recognize a smaller capacity). In layman’s terms, Li-ion batteries will store more energy than same-sized NiMH cells and hold that energy longer. The downfall for Li-ion has been in the news in recent years. If they are shorted or overcharged, they are susceptible to explosion, and thus require integrated circuitry to carefully monitor voltage.
Apple brought Li-poly batteries to the forefront recently, although the technology has been available for use for over a decade. Li-poly differentiates itself from Li-ion in that it does not require a hard casing and can be shaped to fit as needed. The fact that there is no cell spacing allows energy density to improve by over 20% compared to Li-ion designs. Finally, Li-poly is cheaper to manufacture than Li-ion and is less prone to physical damage.
Some Li-poly batteries are not removable. I would hesitate buying a notebook with a built-in Li-poly battery (compared to a removable Li-poly or Li-ion battery), simply because you are left with a useless notebook when the battery dies. The ability to swap batteries midway through your workday and maintain your productivity without being near AC power is an important consideration to keep in mind. It also underscores the ultimate reason to purchase an additional battery: extra power, on hand, anytime.
Finally, regardless of which chemistry your battery uses, all batteries will degrade over time, with use. A reasonable ballpark figure to work with is approx. 10%-20% per year. You may not notice after a year or two, but a four- or five-year-old notebook will more than likely need a battery replacement.
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There aren't any options in the bios so is there software to undervolt my notebook's CPU?
They rate Amp-hours per cell. I.e. 2.2amp hours is only for one cell of a multi-cell battery? Confusing.
w4ffles: I use RMClock myself (there should be a free version online). It lets you set profiles so you can specify the maximum speed and voltage of your CPU (and various other levels depending on CPu usage). I use it to underclock and undervolt my desktop when not in use, but to crank the CPU up to max when doing heavy loads (which the application detects automatically and adjusts on the fly).
It can take a learning curve to use, but even the free version is very powerful.
Just something to point out, DDR3 is a power saving component in notebooks right now since it runs at a lower Voltage than DDR2. The difference isn't particularly significant, but DDR3 will give you maybe 5-10% more runtime.
Most people think of DDR3 as a perfomance increase, but with the limited frequencies of current soDIMMs, DDR3 for laptops is only on par with current DDR2 notebook RAM, if that.
My Compaq V5000 is still going strong after 5 years. I chose to go with Sempron and the matte screen (I planned to work outside and the glossy was brighter by default). Also got the 12 cell. I play Starcraft, Diablo 2 so the ati 200M worked perfectly, and then work related stuff (lasts about 6 hours watching downloaded media).
Great article, these were the things I considered when choosing components for my laptop, as I never knew when I would be close to an outlet.
andetghddn -
P.S. The v5000 laptop also cost about $450 direct from hp.
They rate Amp-hours per cell. I.e. 2.2amp hours is only for one cell of a multi-cell battery? Confusing.w4ffles: I use RMClock myself (there should be a free version online). It lets you set profiles so you can specify the maximum speed and voltage of your CPU (and various other levels depending on CPu usage). I use it to underclock and undervolt my desktop when not in use, but to crank the CPU up to max when doing heavy loads (which the application detects automatically and adjusts on the fly).It can take a learning curve to use, but even the free version is very powerful.
RMClock is the defacto software in use on notebooks at the moment, and what I would recommend. While I don't want to get into a full-blown guide here, it is also important to stress the CPU while testing your voltages before you really play with RMClock. It does take some learning, but anyone with the skills can do it.
Cool - now I can get a 30% off coupon at HP. Nice article!
I always enjoy having a laptop battery that doesn't start a fire.
I have a busniess notebook for work and aside from the programs I use everyday, don't know that much about computers. The biggest thing for me with buying an extended battery was the price. HP wanted a boat load for it, which is really a rip off. I checked different site for about 2 1/2 days and ended up getting one from NoteBatt.com for like half or something close to it. Couple of other sites were the same way. It's just nuts to think that other companies are selling pretty much the same battery for much less. Oh, and it has been completely bug free since I got it, something HP told me would not happen.
Even with 30% off coupon I think HP batteries are very expensive. I also was scared about fire when I started looking for a new battery for my HP and I found a very high quality batteries at www.newpcbattery.com. I chose that site because battery manufacturer located in USA, not in China.