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Using Discarded Laptop Batteries To Power Lights
mrspoonsi sends news of an IBM study (PDF) which found that discarded laptop batteries could be used to power lights in areas where there's little or no electrical grid. Of the sample IBM tested, 70% of the used batteries were able to power an LED light for more than four hours every day throughout an entire year.
The concept was trialed in the Indian city of Bangalore this year. The adapted power packs are expected to prove popular with street vendors, who are not on the electric grid, as well as poor families living in slums. The IBM team created what they called an UrJar — a device that uses lithium-ion cells from the old batteries to power low-energy DC devices, such as a light. The researchers are aiming to help the approximately 400 million people in India who are off grid.
If you're discarding laptop batteries while they can still hold a charge
You are likely to discard the battery as soon as it can no longer hold a satisfactory capacity for your application. The battery is no longer effective for your use at that point, and you're wasting electricity time and $$$ and not getting the portability you want.
Based on the IBM study:
Sure, your laptop battery may not hold enough charge to power your laptop any more, but an LED needs a lot less power than your laptop, depending on what it's being used for. Most of the lightbulb-replacement LED bulbs I've seen want 9-23 watts, but the flashlights are more like 3w, and nightlights are more like 0.5 watts.
Also, that laptop battery is a battery of cells, and they usually don't all die at once. They may not be in good enough shape to remanufacture into new laptop batteries, but still have enough of them good enough to disassemble at third-world labor costs to recover cells for off-grid LED lighting.
Bill Stewart
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Do the communities who benefit from the secondary-use life of these batteries have the infrastructure and culture to properly recycle the materials; or will they end up in landfill/discarded into the environment?
The problem with Lithium ion batteries is that their failure mode is often really obnoxious. When one cell in a pack fails, the battery ceases to be usable as a laptop battery, because as soon as you discharge down below some arbitrary fraction of its capacity, the voltage suddenly plummets below the operating threshold for your hardware, and the machine shuts itself off unceremoniously, with no opportunity to save your work or shut down cleanly. If the failure percentage is 5%, a few people will put up with it, and make a mental note not to let it get too low. If the battery drops dead at 60%, or if the failure point is a bit more variable, then you have to be pretty seriously hardcore to keep using the battery, because you risk losing all your data if you do.
However, under a lighter current draw, those same batteries will behave much better. The voltage probably won't sag at all, because (if I understand the problem correctly) there's enough time for the charge to properly redistribute itself across the entire pack even with a single, high-resistance (bad) cell. And even if it does sag, a voltage sag on an LED light would just make it put out less light, which isn't a big deal. For that matter, if they're cracking open the packs, they could probably fully utilize most of the cells for years before they would fail, so long as they toss the cells that have failed.
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Dude, I was soldering tabbed NiCD batteries into packs for my RC car when I was 12. Being afraid of small, low-voltage power sources because high-power sources could hurt you is like being afraid of house cats because lions and tigers can hurt you.
An incredibly useful amount of light can be provided by an LED headlamp for many, hours running on just a pair of AAA batteries. I hang it around camp all the time as a lantern providing indirect light, or more than enough direct light to read by. And that represents about 3Wh of capacity, versus the 60Wh for a smallish laptop battery. That small battery, reduced to only 10% of it's already meager original capacity, is not going to give you even remotely enough power for your laptop to be portable anymore, but would still provide twice the capacity of that headlamp. At 20% capacity you're probably overdue for a battery replacement if mobility is important to you, and that will give you 8 AAAs worth of power.
So we've got what, maybe $8 worth of decent quality NiMH-equivalnets right there, being thrown away as nicely packaged trash? If you can harness that trash stream to make solar lamps you could improve a lot of lives, while making sure those batteries get every last bit of life wrung out of them by people who know the value of a nickel.
I see two potential problems though - the first is pollution: we'd be interrupting a recycling-stream (one can hope) to re-purpose the batteries. We'd want to make sure they get back into that stream when fully dead. Hopefully there's large enough profit margins or subsidies in the system that people can make money buying dead batteries from people in the slums and villages to sell to the recycling plants, otherwise we have to trust to sufficient environmental awareness to keep these things out of the rubbish heaps.
The second is the fire hazard. I'm not certain how much, the fire hazard of a Li-ion battery increases when it's on its last legs, but distributing large quantities of low-individual-risk firebombs among the world's slums could be unfortunate.
--- Most topics have many sides worth arguing, allow me to take one opposite you.