Dec 5, 2007
If you’ve just bought an iPhone, you’re probably expecting many happy years of battery power. Well, not so fast. Laptop batteries are very similar to rechargeable batteries in other devices, they wear out. I’ve had my current laptop for about 18 months and in the last few weeks I’ve noticed that I’m not getting quite the battery life from it that I was when I first bought it. I used to be able to run for about 3 hours doing wordprocessing, email, and web browsing even on a wireless connection. Lately, however, the lithium battery seems to run down within an hour or so, which is a real pain when I’m offsite.
I checked out Battery University to see if there is anything I can do to get my battery life back to normal. Apparently, there isn’t, and as a chemist, I should have known that (it’s all about crystallization of the components and such). It turns out that I basically broke all the rules concerning lithium battery use. Here’s a quick run down of what you should and shouldn’t do to help maintain the health of any lithium battery whether in a laptop, iPhone (other hybrid devices are available):
- Avoid frequent full discharges; regular partial discharges and an occasional full discharge are better. Lithium batteries have no charge “memory”, unlike NiCd batteries, so frequent recharging does no harm.
- Carry out a deliberate full discharge once every 30 charges, you can do this by simply running the battery down in the equipment (if you have power management enabled switch it off temporarily and make sure you are not running any critical software). An advantage of this approach is that it helps calibrate the battery fuel gauge and avoids premature hybernation.
- Keep the lithium-ion battery cool. Heat is a killer for batteries. Don’t leave your device in a hot car or window ledge, don’t use a laptop on your lap (how’s that for irony), above about 45 Celsius, a lithium will wear out very quickly.
- If you’re running on fixed power, think about removing the battery from a laptop to reduce the impact of internal heat. Of course, you lose the mobility advantage of the battery and also the safety should your mains power go down.
- Don’t buy spare lithium-ion batteries to use later on. Even when not in use a lithium battery will age.
- If you do have a spare lithium-ion battery, use one most of the time and keep the other wrapped in a hermetically sealed plastic box or bag in the refrigerator, but do not freeze your battery.
- If you have to store your battery or device, make sure it’s charged to about 40% before leaving it for extended periods.
- If you’ve just bought a new device, follow this advice and pop back in a year or so to let me know how you got on. After 12 months any lithium battery no matter how well looked after may lose up to 20% of its charging capacity but if you’ve lost more than that, then you probably broke the Battery University rules.
This post was originally destined for my blogging and browsing tips site Significant Figures, for more of the same and different again, check out the Sig Figs site at sciencetext.com