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Is it better to use laptop on battery or on AC power?

I keep my Thinkpad T60 laptop plugged in all the time. Should I remove my battery or if not, should I drain it occassionally?

If it should be drained, how often?



3 Answers 3


No - you can leave it in.

People who think it should be removed, or people who advise it are usually thinking about the "Memory Effect". NiCd (Nickel-cadmium) batteries were affected by this, however new Li-ion (Lithium-ion) are not affected.

On some laptops, (especially "green" laptops with specialised power chips) you will get poor performance with the battery removed as it under-performs. For example MacBook Performance Plunges When Battery Removed.

Any intelligent laptop from the past few years should be intelligent to discharge and rotate frequently meaning that you do not need to manually drain it. For example, my laptop is plugged in (usually) 24x7, and every 24-48 or so hours, it drops to 95% and recharges.

Lastly, One bonus of having a laptop is that you get a "free" UPS! of course, if you have a separate UPS, forget this point, but if there is a power cut, you may be happy that you left it in.

  • 2
    That's not entirely true. Remember that the self-discharge of Li-Ion batteries increases as temperature rises. Keeping the battery in the laptop usually just gives it more opportunity to get warm or even hot which rapidly accelerates capacity loss. However, ThinkPads (or at least the R and T60 series) are engineered that the battery isn't near anything that gets warm. I was pleasantly surprised when I found this out.
    – Joey
    Jan 6, 2010 at 7:06
  • 2
    ThinkPads are solid laptops. Terrific Engineering.
    – user1931
    Jan 6, 2010 at 7:46

A great tip for extending the life of a laptop battery is – don’t use it! No seriously, if your laptop is connected to the mains, then you should in general remove the battery to extend its life.

From 10 Tips to make your Laptop Battery last longer:

  1. If you do not use your laptop for extended periods of time (a week or more), remove the battery pack from the laptop.
  2. Do not expose the battery to high heat or freezing temperatures. Hot batteries discharge very quickly, and cold ones can't create as much power.
  3. Make sure to plug your laptop charger adapter into a UPS and not directly into a power outlet or surge protector.
  4. If you have a nickel-metal hydride battery, completely drain and recharge the battery once a month to maximize its capacity to hold a charge.
  5. Fully charge new battery packs before use. New pack needs to be fully charged and discharged (cycled) a few times before it can condition to full capacity.
  6. For laptops that work as Desktop Replacement, the battery should be re-installed every 3-4 weeks and allowed to fully discharge.
  7. Leaving a battery in a laptop while using an electrical outlet for long periods of time will keep the battery in a constant state of charging up and that will reduce the life cycle of the battery.
  8. Use standby to save power when you will be away from the computer for a short time while working.
  9. Use hibernation to save power when you will be away from the computer for an extended time while working.

This may perhaps be considered old school thinking. Each battery has a maximum charge and discharge cycle. Even with a smart battery, the battery will be subjected to this charge and discharge cycle when plugged in. What do you think will happen when this limit is achieved? Also, consider Johannes Rossel's point about capacity loss due to heat. Again, with newer designs, the high heat components are kept further away or more insulated from the battery portion, but even then there is an additional heat source for the battery.

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