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.

Comments

Re:sorry, all my laptop batteries are dead

[mysidia]

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:

Fig. 2 shows the charge capacity as a percentage of designed capacity for the investigated laptop battery packs. We found that although there was a significant variation in the residual capacities, the mean value was 64% while the median was 73%.

The mean value corresponds to more than 50 Wh of capacity for the batteries tested, which is sufficient to power a 3 W LED light bulb, a 6 W DC fan and a 3.5 W mobile phone charger simultaneously, for around 4 hours

Therefore, discarded laptop batteries appear to have satisfactory potential for reuse as backup energy sources to power low energy DC devices

40 watt PC battery vs. 3 watt LED

[billstewart]

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.

What happens to these at the true end-of-life?

[JonathanR]

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?

Re:sorry, all my laptop batteries are dead

[Immerman]

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.