1.21 Gigawatts!

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Lithium Ion batteries are everywhere these days. Cellphones, Notebooks, iPods, PDAs etc. Even though we’ve come a long way from NiCd batteries which built up memories, Li-ion batteries however, are still susceptible to losing their chutzpah. Li-ion batteries are generally good for 300-500 charge/discharge cycles (2-3 years), and it’s not a good idea to let them discharge completely. I find this fact particularly interesting because 90% of people at electronic stores have told me to only recharge a battery once it has fully discharged. This might have been the case with NiCd batteries but is not applicable to the Li-ion batteries used in our electrical devices today.

According to batteryuniversity.com, for example, a worst case scenario is when using a notebook plugged into an AC socket with it’s battery fully charged. The problem comes in with the amount of heat the battery is subjected to, as heat decreases it’s lifespan. I’d suggest removing the battery when you’re working off an AC socket.

A Li-ion battery should also never be stored when it’s fully discharged. Apparently the best charge to keep a battery stored at is around 40% (how manufacturers ship the batteries). So to be safe, apply a charge to the battery before storing it, and charge fully before use.

A few guidelines taken from batteryuniversity.com:

• Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.
• Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.
• If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge.

This entry was posted on Tuesday, June 5th, 2007 at 10:17 and is filed under hardware. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.