Get More Life From Your Li-ions

A few DIY tricks and must-read resources for making your lithium-based laptop batteries last

By Mikey Sklar Posted 09.16.2009 at 12:00 pm 9 Comments

iBook battery Mikey Sklar

I'm not sure what sparked my battery obsession. Perhaps it was the installation of 3,000 lbs of lead-acid batteries used to power my homestead. Shortly after that, I found myself zapping old Ni-CD based battery packs with a welder to bring the once-dead batteries back to life. Then I began repacking the cells of other household items, including my iRobot vac and my Macbook. Now I regularly visit a local auto supply, combing through batteries for signs of life. My office is littered with a hodge-podge of Ni-CD, lead-acid and lithium-based cells that are patiently awaiting repairs and a new purpose.

Here's what I've learned about keeping batteries in shape, and rehabbing old ones from the junk heap.

Whenever I want to learn more about a particular battery chemistry, I refer to this book "Batteries in a Portable World." You can pickup a print version on Amazon for $4.75. The book is also available for free on-line. It contains a wealth of information.

For example, one of the keys to maximizing any battery's potential is maintaining the right charge levels and temperatures. Storing a lithium-ion battery at a too-warm 77°F with a full charge will reduce the capacity by 20 percent in the first year alone. (This has to make you wonder how the lithium-ion battery packs in the new Tesla Roadster will fair over time.)

Here are a few more tips for getting the longest life from the lithium-based batteries in your laptops and power tools:

Avoid heat
Remove the battery when using a power supply for a extended duration
When not in use, store the battery at a 40 percent charge and keep it in the refrigerator (do not freeze)
Buy fresh batteries from a retailer who sells a lot of batteries (avoid old batteries)
A full discharge after every 30 charges will help recalibrate the battery

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9 Comments

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wilsontaylor99

09/17/09 at 8:14 am

OH wow, what a great idea!

Jess
www.web-privacy.de.tc

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johnkilmy

09/17/09 at 9:58 am

Wow that is pretty awesome! http://www.electroniccigarettesinc.com

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rickyfr

09/17/09 at 11:16 am

Regarding your statement about laptop batteries, "Remove the battery when using a power supply for a extended duration." This will slow down MacBooks and MacBook Pros. They work much faster when connected to A/C and the battery is in the computer.

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Phoghat

from Elmhurst, NY

09/19/09 at 2:31 pm

Where can I find information to rebuild the pack on my Compaq laptop so it will last longer?

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Mikey Sklar

09/22/09 at 3:57 pm

rickfr: While I have not done to the work to confirm that performance drops when the battery is removed I have seen a related power anomaly on macs.

When the laptop power supply is plugged into the mac the system performance goes up (even if the power supply is not plugged into the wall). Yes, a dead power supply changes performance.

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Vertman

09/24/09 at 1:34 pm

Mikey, Any ideas for the small 1.5 volt Li-ion rechargeable kind from Energizer? Some old units begin blinking in the charge when attempts to re-charge. Very frustrating.

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Mikey Sklar

09/24/09 at 7:00 pm

Vertman: At the 1.5V level you might be out of luck.

I use a RC car charger which can charge pretty much any common chemistry (Li-ion, Li-Poly, Ni-CD, NIMH, and Pb. Unfortunately, this sort of charger only recognizes 3.7V li-ion stepping so it can't deal with a 1.5V. I do recommend this kind of charger to deal with batteries that don't behave well in their normal charger. The RC car chargers can be set to charge at very low currents and even do discharges so you can determine the total battery capacity.

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John Warden

12/08/09 at 7:13 pm

That's incredible! Wonder if this type of ingenuity could be applied to battery powered cars as well.

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John Warden

12/08/09 at 7:56 pm

Sorry for the double post didn't think it went through.