laptop battery question

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I have a Dell Laptop that I typically use by plugging in to my house electric power. I seldom use the battery. Someone told me that if I take my battery out of the laptop, I will extend its life. They said I should only put the battery back when I am going to use the laptop on battery power. Is this a correct option?

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Hi trebor,

As heat is the main enemy of laptop batteries, removing the battery when running on AC is recommended for better battery life. The down side is if there is a power failure, your built in UPS (which your laptop battery serves as in those situations) will not be there to smoothly continue operation while you are using your laptop. If you live in an area where power is stable, then removing the battery when on AC should help extend its operational life.

If you do remove your battery, don’t let it discharge to zero for extended periods of storage. Periodically place it back in your laptop to fully recharge it. There are also a lot of recommendations about how low to allow lithium ion batteries to discharge before fully recharging, but these recommendations vary. Perhaps another Lounger has some documented specific recommendations on this issue. I generally allow my laptop batteries to almost fully discharge once per month, and recharge at various levels the rest of the time.

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Hi trebor, this is what I was told.
First use, full charge without interuption, then use on battery till laptop auto shuts down. repeat 3 times. This helps extend battery life.
To use on AC without the battery, remove it when power is about 50%. Fully charge monthly and remove at 50 %.

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Hi, trebor-

I hope that this article will be helpful. To skip the technical stuff, the practical advice is found under Figure 3.

John

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Presuming this is a recent laptop with a Lithium-ion battery then the best method for longevity is to keep the battery cool and keep its charge between 40% and 70%.

As someone has pointed out, the problem with running without the battery installed is lost work if the mains power fails. However, if you live in an area that has a reliable supply, then removing the battery when the charge is around 70% is a good plan. And store it somewhere cool – which will considerably prolong its life. The heat generated by the laptop passing across to the battery is part of the cause of shortened battery life.

You may find that occasionally you may need to go through a complete discharge cycle to keep the laptop power management in sync with the battery. There should be a setting in BIOS that you can enable which allows the laptop to totally discharge the battery (disabling all the usual battery low and automatic shut-down options). Once the battery is totally discharged, plug the laptop into the main supply and switch on. Leave the laptop connected until the battery is fully charged again. It may be necessary to do this several times in succession to sync the power management properly. However, only do this if you believe it is really necessary as totally discharging Li-ion batteries is BAD and will shorten their life. As I said above, try to keep them between 40% – 70% and running cool for longevity.

Ni-Mh and Ni-cad are totally different, of course.

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If the idea is to prolong the Li-ion battery life, keep the battery around 40-60% charged (or 30-70% for practicality when using it). Fully charged state is actually less durable. Below 10% is a bad choice, shortening the life of the battery. High temperature too. Wrap the 40-60% charged battery in tight plastic Saran wrap to avoid condensation. Then put it in the freezer. This keep it the longest.

The laptop ‘oil gauge’, the battery gauge, needs to be calibrated (actually matched) to the battery at the condition the battery is at. Despite discharging below 10% is not good, you need to let the laptop discharges the battery until the gauge shows nearly empty. Once it is ‘calibrated’. The gauge accurately reflects the total energy charged or discharged.

The less number of times the battery discharges to 10% or lower, the less damage to long life. So this ‘calibration’ should be done as little as possible. When it is 30%, charge it. When it is 70%, disconnect the AC adapter to prevent charging.

The best practice is to charge/discharge between 40-60%. To prevent power interruption when the battery is out, you might use an uninterpretable power supply (UPS).

On the other hand, battery lasts a while under normal ‘abuse’ (about 2 years). After market laptop battery is not expensive either, around $40 from Amazon.com. I would go for convenience, than the inconvenience.

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