Prototype SunCat batteries enable solar charging

(Credit: Knut Karlsen)

Solar-powered phones like the Samsung Blue Earth are great eco-friendly concepts, in theory.

But let's be frank with ourselves. We won't see these sun-worshipping devices replacing mainstream handsets in the near future. Meanwhile, we still have a mountain of gadgets that need to be juiced regularly, which is why designer Knut Karlsen's idea of integrating flexible solar cells onto rechargeable batteries could be a more immediate solution to reducing our carbon footprint.

(Credit: Knut Karlsen)

Named after a feline basking in the sun, SunCat involves flexible solar-cell strips glued to nickel metal hydride rechargeable cells.

With a conductive silver pen and flat wires recycled from a broken Canon lens, Knut managed to get a weak trickle charge connection. He admitted that the first prototype wasn't ideal, but he's working on a second model that may include a display for checking battery life and capacitors for more efficient charging.

A downside to this is that the battery will have to be smaller, according to Knut, if these extra components were to be added into a regular cell. But we're confident that these issues can be worked out along the way.

(Source: Crave Asia via Oh Gizmo)

[Someone-else]

Just as the Samsung Blue Earth, I don't see these batteries as green, the amount of energy saved by using them is minimum, it's much better to have a solar panel on your roof, then in you cellphone or batteries.
But they aren't a bad idea, as they could let you use them for longer before needing to recharge.

[DarkHawke]

"...they could let you use them for longer before needing to recharge"? And that would be, how? Are you one to pop open your flashlight so you can set the batteries out in the sun (if there is any) to charge? Or do you have transparent cases on all your devices that use regular batteries? Just as with the solar-powered cell phone, this is a feel-good idea, not a works-well idea. You were right the first time: better to have, say, a solar powered charger with a permanently mounted panel that continuously (at least during the daytime!) charges batteries that you swap out as needed. The ultimate limitation, as I parenthetically noted above, is sufficient available sunlight to do the job, which is at best an open proposition. And even then, would it be cost-effective vs. chargers that you just plug into the wall?

[Someone-else]

Just as the Samsung Blue Earth, I don't see these batteries as green, the amount of energy saved by using them is minimum, it's much better to have a solar panel on your roof, then in you cellphone or batteries.
But they aren't a bad idea, as they could let you use them for longer before needing to recharge.

[Rants&Raves]

Not sure that leaving batteries out in the sun is a good idea; won`t it damage the chemicals inside ? Can`t they explode or leak ?

[stringarray]

I could see this as being one of those "cool" REI (or outdoor store) buys but nothing mainstream. However, Interesting point regarding the possibility of the sun's heat doing damage to the battery itself. This will probably be vaporware...

[Roman1024A]

Solar cell coating on batteries as Immediate solution to Reducing carbon footprint??? What a nonsense! I guess author of this article would do better to educate himself on current energy consumptions usage statistics rather than how to stick currently popular buzzwords into his articles.

Amount of energy used in portable devices is miniscule compared to energy we use for things like transportation, heating and cooling. If all batteries have solar cell coating today - it would reduce our carbon footpring by less than by 0.1%. Also solar cells would be much better used when mounted on roofs rather than wasted for battery coating.

[viper396]

I can see an irony in this if you intend on using them for a flashlight or similiar lighting purposes. It's most likely to be dark out when you need the flashlight the most, hence no easy way to recharge the batteries.

[OStrolphant]

if your batteries are dead your batteries are dead. rechargeable or not.

[U. Tripps]

There is no way this can ever be as efficient as a rooftop solar panel. Obviously. However, that's not the point. A battery is all about portability. If you are out in the world with your batteries dying, you probably don't have the home charging station available.

So, for this to be useful as an outside-the-home solution, they need to charge pretty fast. This probably needs some work, but it is a pretty compelling idea.

[carlhage]

Do the math: A flexible cell might be 50W/m2 or 5mw/cm2 in full sun. An AA battery is about 3mWh, and
there will be a small area, maybe 3cm2, but reflection at shallow angles might reduce this to 1 or 2 cm2. Also, it won't be at the maximum power point, so 1/2 the power is lost. It might need 1000 hours of full-sun to charge-- probably longer than the self-discharge rate.

A better idea would be to have "green" graduation wear, where the cap on engineering graduates have
solar cells on top. The larger size might generate around 3W peak if the cap is tilted slightly and worn outside in the sun. Add a clip for a battery (perhaps in place of the tassel), and it could be used by hikers to keep the GPS and camera charged.