Super Battery Developed

Winga

The boffins at MIT have come up with a battery that recharges itself in a few seconds and might never need replacing.

Rechargable and disposable batteries use a chemical reaction to produce energy. Although effective, after many charges and discharges the battery loses capacity and needs to be replaced.
The MIT researchers covered the electrodes with nanotubes which increased the surface area. This enabled the capacitor to store more energy.
In tests, the batteries could be re-used many times and could be recharged in a matter of seconds rather than a matter of hours.

The technology would be good for laptops, hearing aids and battery powered cars. Of course having batteries that are recharged quickly take humanity one step closer to total redundancy of the male.

Source: The Inquirer

RWB

How many died bringing us this information?

airbornflght

I want one.

EMT

I'm sure you can't charge from the wall in a matter of seconds... pulling 1000W out of the wall should be about 20A so you'd blow a fuse if you charged any faster. If it's 100% efficient and then your laptop uses 100W, you'd get 10 times the battery life as the time you spent with the thing plugged in. So the practical limit is, you could charge 2 hrs of battery in a minimum of 12 minutes.

But it sounds like great news nonetheless

edit-- See my third post in this thread (post#12), I think it's 6 minutes instead of 12.

airbornflght

12 minutes is still a very short charge time.

and EMT, there is a slight error in your calculations. Considering that V in the us is 110, then 1000watts would take 9.09 amperes.

Most house sockets are wired to a 15 amp circuit, which will give you 1650 watts, some are wired 20amps with a special socket which will give 2200 watts.

And you are talking about a capacitor, not a battery. Capacitors can charge as fast as the current is given to them. and most laptop baterries are around 30a/hrs I believe? maybe less? im not sure. so if you are figuring 12 volts at 30 a/hrs, that is 360 watt/hrs of electricity, and if the charge can do 1000 hours, if not more, then it sholud be able to charge in 360/1000=.36 hours = 21.6 minutes.

I am pretty damn sure that my figures are off, because it should be much quicker than that. I'm too tired. capacitors should be able to charge very wuickle. anyway, om to tires to typw anymore.

Enverex

Well it's 240v over here with most things on 13A fuses, that makes over 3000W. Where did you get your figures EMT? Also, you say 2 hours of battery but that's highly machine specific considering they all vary on their amp and voltage outputs as well as having different mAH capacities...

RWB

In the US the Voltages are 110 to 120V over what I guess are 20A lines.

EMT

Where did I get my figures... I made them up. Well, 100W is probably an upper limit on non-DTR laptops (I think mine is closer to 70). Just using round figures to make the calculation simpler.

You can't just multiply AC voltage times AC current to get Watts (though that works for DC). The reason is that you're calculating average power, not peak power, and the voltage times current wave results in a sine^2 power wave. The average of a sine^2 wave is half of its peak, so (using round figures) 100VAC * 20AAC = 2000Wpeak or 1000Wrms.

airbornflight, you're right, I'm not talking about any specific kind of battery. Just the limit on how fast you can store the required energy for a certain period of time, based on device's power consumption and how much power you can get from the wall.

edit-- See my third post in this thread (post#12), I think it's 6 minutes instead of 12, 2000W instead of 1000, due to the fact that the 110V and 20A figures are already RMS instead of amplitude. Thanks airbornflight

airbornflght

EMT wrote:

Where did I get my figures... I made them up. Well, 100W is probably an upper limit on non-DTR laptops (I think mine is closer to 70). Just using round figures to make the calculation simpler.

You can't just multiply AC voltage times AC current to get Watts (though that works for DC). The reason is that you're calculating average power, not peak power, and the voltage times current wave results in a sine^2 power wave. The average of a sine^2 wave is half of its peak, so (using round figures) 100VAC * 20AAC = 2000Wpeak or 1000Wrms.

airbornflight, you're right, I'm not talking about any specific kind of battery. Just the limit on how fast you can store the required energy for a certain period of time, based on device's power consumption and how much power you can get from the wall.

well, I'm not an ee, but from what I know about AC voltage is that it is positive half of the time, and negative half of the time. so wouldnt that come out to 0 volts average?

EMT, you may very well know more than me, but the reason that I think my figures are correct is because I have a 1500 watts space heater in my room that runs on a 15 amp circuit.

Enverex

I also have a 2000W Vacuum Cleaner.

airbornflght

Yeh, EMT, I have done some poking around and it appears that you may be wrong on figuring the wattage. I have went to two or three sites, and they all say that P=V*I no matter if it is AC or DC. The way that I have learned and always believed is the only difference between the two is the way that the electricity is transmitted. Electricity always goes from the power source to the ground. So DC is a direct route from the power pole goes through whatever circuitry, and then grounds out. And EMT, I have also called a friend, and he said that the power actually ocsilates between ~170 and ~-170 volts, and the rms of that is between 110-120 depending on what the peak voltages are.

The way I was taught ac, was that the power and negative are on one pole, and they share a common ground, which the common term comes from 3 phase power, because all of the 3 phases share one common ground. Anymore than that I do not really know.

EMT

Hmmm... I think you've caught me. I was thinking of amplitude of voltage and current, but it's certainly 110V rms, and actually probably 20A rms for fuses so you can multiply them. So you CAN pull 2000W average and so you can get those 2 hours of battery life for 6 minutes spent charging at maximum current.

Well at least that's an interesting number to know. And.. good thing they haven't given me my degree yet

airbornflght

lol. are you going for EE, I thought about it, for 2 seconds, then I remembered as much as I like that stuff, I dont want to spend my life doing it. and I think hat the whole 15a, 20a thing differs on region and on wiring codes. In oklahoma, I am pretty sure that we have to have a 20amp socket to have a 20 amps breaker, otherwise, if we are using the plain jane wall socket, then we can only have a 15amp breaker at the breaker box. That may just be a code of the city I live in, I'm not sure.

EMT

I'm in CompE so it's not exactly EE, but the curriculums are very close.

airbornflght

yeh, I was thinking of doing CE, but I like programming and networking more than I would like developing a processor or something else, so I am going to go into Computer Science, I here the curriculum is still really hard though.