ShakEnergy battery ???
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kaichu dento
Flashaholic
I'd like to give one a try! A battery you can always carry as backup, and if it's low, just recharge it!
Bones
Enlightened
A cut-away:
If done right, this really could be a life-saver.
Low self-discharge would certainly be a plus, especially if they could partner with Sanyo to take advantage of the Eneloop's voltage sustainability and overall durability. It would also give the cell instant credibility if they could advertise that it utilizes Eneloop technology.
O.T...
You'll definitely know you've 'arrived' when it's as the owner of a little (57 metre) eco-friendly yacht like this:
Oh well...
If done right, this really could be a life-saver.
Low self-discharge would certainly be a plus, especially if they could partner with Sanyo to take advantage of the Eneloop's voltage sustainability and overall durability. It would also give the cell instant credibility if they could advertise that it utilizes Eneloop technology.
O.T...
You'll definitely know you've 'arrived' when it's as the owner of a little (57 metre) eco-friendly yacht like this:
Oh well...
question:
when shake lights are considered junk, in great agreement here,
why should such a cell should suddenly not be junk?
wont work in x years,
if works, the engery from shaking is a joke,
if works, the energy stored is a joke
.
.
.
survival light: low output, lithium batteries
anything other: just keep an eye on Your Ni-Mhs, Li-Ions, ...
when shake lights are considered junk, in great agreement here,
why should such a cell should suddenly not be junk?
wont work in x years,
if works, the engery from shaking is a joke,
if works, the energy stored is a joke
.
.
.
survival light: low output, lithium batteries
anything other: just keep an eye on Your Ni-Mhs, Li-Ions, ...
lolzertank
Enlightened
I agree with yellow. The generator is not going to make much current, and shaking AA cells all day will get boring FAST.
VidPro
Flashlight Enthusiast
uhh is this like a basketball battery? distributed by O'neils? i heard he was diversifying into many areas , but batteries
that is sorta cool, who woulda thought you could stuff all that in there like that, next thing you know they will make self winding watches :thinking:
that is sorta cool, who woulda thought you could stuff all that in there like that, next thing you know they will make self winding watches :thinking:
Bones
Enlightened
While these cells may or may not end up being junk, I certainly don't include the original AIT shake light in that category. In fact, it would probably be my first choice for a basic flashlight for my ultimate emergency kit:
http://www.flashlightreviews.com ... ait_nightstar2sc.htm
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qwertyydude
Flashlight Enthusiast
- Joined
- Aug 10, 2008
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- 1,115
Now I'd like to ask if this design could be adapted to solar with a flexible solar cell wrapped on the outside just leave batteries in the sun and they charge themselves.
kaichu dento
Flashaholic
Every time Columbus sets sail, someone predicts failure.
Fortunately mankind has not let the failures of those before act as a damper.
Fortunately mankind has not let the failures of those before act as a damper.
Mr Happy
Flashlight Enthusiast
Let's do a little engineering analysis. We will make some gross assumptions and see where it takes us:
Firstly, assume the sliding magnet weighs about 10 g and that with vigorous shaking we can get it up to a speed of about 30 m/s. This will give it a kinetic energy of
E = 0.5mv² = (0.5)(0.01 kg)(30 m/s)² = 4.5 J
Next, assume that 10% of this energy is transferred via the coil to the battery per pass of the magnet, and that with vigorous shaking we can achieve 10 passes per second. This would give us an energy transfer to the battery of about
W = (4.5 J)(0.1)(10/s) = 4.5 J/s = 4.5 W
Now let's look at the battery. For a typical half size NiMH AA cell we can assume a capacity of 1000 mAh (1 Ah). Multiplying the capacity by the average voltage we can estimate the stored energy as
E = (1 Ah)(3600 s/h)(1.2 V) = 4300 Ws = 4300 J
Dividing the energy storage by the charge rate we have an estimated time to charge of
t = (4300 J)/(4.5 W) = 960 s = 16 min
Not withstanding that we have made all sorts of assumptions here, I think we can conclude that to fully charge an empty battery would require it to be shaken vigorously for many, many minutes. It is a fair bet that your arm would cramp up before the battery was charged. It's only going to be good for dire emergencies.
[Edit: all good engineers do a sanity check. Let's do one. A charge rate of 4.5 W into a NiMH cell is a current of about 3 A. To charge the cell from empty is also a charge rate of about 4C. Both of these values, 3 A from a little coil and 4C charge rate are way outside the bounds of possibility. I think we have to conclude that far from taking about 15 minutes to charge, it is more likely to be several hours. This just isn't going to work.]
Firstly, assume the sliding magnet weighs about 10 g and that with vigorous shaking we can get it up to a speed of about 30 m/s. This will give it a kinetic energy of
E = 0.5mv² = (0.5)(0.01 kg)(30 m/s)² = 4.5 J
Next, assume that 10% of this energy is transferred via the coil to the battery per pass of the magnet, and that with vigorous shaking we can achieve 10 passes per second. This would give us an energy transfer to the battery of about
W = (4.5 J)(0.1)(10/s) = 4.5 J/s = 4.5 W
Now let's look at the battery. For a typical half size NiMH AA cell we can assume a capacity of 1000 mAh (1 Ah). Multiplying the capacity by the average voltage we can estimate the stored energy as
E = (1 Ah)(3600 s/h)(1.2 V) = 4300 Ws = 4300 J
Dividing the energy storage by the charge rate we have an estimated time to charge of
t = (4300 J)/(4.5 W) = 960 s = 16 min
Not withstanding that we have made all sorts of assumptions here, I think we can conclude that to fully charge an empty battery would require it to be shaken vigorously for many, many minutes. It is a fair bet that your arm would cramp up before the battery was charged. It's only going to be good for dire emergencies.
[Edit: all good engineers do a sanity check. Let's do one. A charge rate of 4.5 W into a NiMH cell is a current of about 3 A. To charge the cell from empty is also a charge rate of about 4C. Both of these values, 3 A from a little coil and 4C charge rate are way outside the bounds of possibility. I think we have to conclude that far from taking about 15 minutes to charge, it is more likely to be several hours. This just isn't going to work.]
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kaichu dento
Flashaholic
Here's and excellent quote from someone who went to a different school than those who use their intelligence to discourage progress.
45/70
Flashlight Enthusiast
Interesting analysis Mr H, and I agree.
One supposition I see that is probably way off, is the magnet weight. Keep in mind, the average AA NiMH cell weighs about 30 grams. If the cutaway view is at all accurate, judging from the size, I'd be surprised if the magnet weighed even a gram. It's difficult to say how long it is, but remember, it is also hollow.
I could see this battery cell concept winning a science fair project competition, but I really don't see it going anywhere in reality.
kaichu dento, Im not saying it won't work, I'm just saying it wouldn't be practical. I'm sure Thomas Edison came up with some impractical inventions as well.
Dave
while that Edison argument is correct in general, You forget to notice one point:
He invented new, but those shake-lights are not new, they have been produced quite a number of times, and NONE of these worked better than to be a showpiece part. Something that has failed several times wont get better by constantly trying to "invent" it as a "new".
It is the motion that is uneffective and boring, even on the short run (much shorter than to charge the cell to any measurable level)
conclusion:
even when "chargers" with lever and cycling motion are not waterproof and not available in a good mechanical quality to have them work for sure in x years time, when they probably will be needed as emergency lights, I will take them any time.
The motion is much better and brutally more charging current can be achieved
but of course that is totally individual point of view, so anyone can use these cells
(PS: imho 18650 size were better. There are no primary cells available in that size and thus such a "self recharging" one might be a better argument, than in AA size)
He invented new, but those shake-lights are not new, they have been produced quite a number of times, and NONE of these worked better than to be a showpiece part. Something that has failed several times wont get better by constantly trying to "invent" it as a "new".
It is the motion that is uneffective and boring, even on the short run (much shorter than to charge the cell to any measurable level)
conclusion:
even when "chargers" with lever and cycling motion are not waterproof and not available in a good mechanical quality to have them work for sure in x years time, when they probably will be needed as emergency lights, I will take them any time.
The motion is much better and brutally more charging current can be achieved
but of course that is totally individual point of view, so anyone can use these cells
(PS: imho 18650 size were better. There are no primary cells available in that size and thus such a "self recharging" one might be a better argument, than in AA size)
Bones
Enlightened
According to this and other independent reviews, the AIT Nightstar will provide 20 minutes of usable light from 30 seconds of motion, which equates to one hour of usable light from 3 evenly spaced 30 second bursts:
http://www.flashlightreviews.com ... ait_nightstar2sc.htm
Considering the light has also proved to be impervious to even grossly abnormal abuse, and can be stored for untold years without a noticeable loss of functionality, I must again disagree with your assessment that it's a failure.
gswitter
Flashlight Enthusiast
I'd be curious to see how well those cells would be charged if you attached them to your shoes.
Or if you drive a lot, attach them to an un-sprung (and non-rotating) part of your vehicle.
Or if you drive a lot, attach them to an un-sprung (and non-rotating) part of your vehicle.
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45/70
Flashlight Enthusiast
This thread is about the Shakenergy AA cell and not about shake lights in general, but still, I thought a comparison of the Nightstar and Shakenergy generation mechanisms would be interesting.
Let's forget about the fact that the Nightstar uses a capacitor rather than charging a battery cell. I'm guessing that in short term applications, a capacitor would be more efficient.
These are just some visual estimations. The first thing I notice is that the Nightstar's magnet travel appears to be about 175mm. The Shakenergy cell appears to have about 15mm of travel or about 1/12th the travel of the Nightstar's. This doesn't take into account the length of the magnet reducing the usable travel, we'll let that go as I don't know the actual length of either of the magnets however, the Nightstar would have an advantage here.
The diameter of the Nightstar magnet would appear to be about 12mm (the body of the light is about 37mm). The Shakenergy magnet I estimate to be about 6mm in diameter. Assuming the length of the two magnets is proportional, that works out to the Shakenergy magnet having about 1/8th the mass of the Nightstar magnet.
Now, assuming the efficiency of the two generation mechanisms is the same, that would give the Shakenergy 12/1 x 8/1 = 96/1, or 1/96th the generation capability.
From this totally "wild guess" estimation, if we were to drive the Nightstar's LED with the Shakenergy AA cell, this would translate to 20 minutes of usable light from 48 minutes of motion, 1 minute of light from 2.4 minutes of motion, one hour of usable light from 60 evenly spaced 2.4 minute motion sessions, or one hour of usable light from a 2hr 24min marathon session.
Due to losses in charging a cell vs. a capacitor, and the loss of efficiency related to miniaturization of the components, I doubt the Shakenergy cell would come anywhere near this performance level. I realize my analysis is unscientific and based merely on dimension comparison, but I just can't see something that small being practical. Again, I'm not saying it wouldn't work, but.....
Dave
Bones
Enlightened
You do realize that you and Mr Happy are taking all the fun out this concept with your damnable 'sanity checks'.
Anyway, it would now be interesting to know what size cell, if any, would provide a workable concept.
Egsise
Banned
Tidal electric power plant?
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