Crank light with capacitor

[ragweed]

That sounds good. Thanks Photon! Information like this is good to know.

 

[Bradlee]

But, is this true? Can the capacitor remain without a charge indefinitely (say, years) and not be adversely affected?

For me, a light like this will probably never get used, but I'd like to have one for the unlikely chance that I actually need it. But only if it truly is unaffected by very extended idle periods.

+1 I hope someone can answer this.

My understanding is that standard electrolytic capacitors could theoretically last indefinitely if not exposed to temperatures that would cause degradation to the electrode/electrolyte interface. I don't understand the electron-level workings of a supercapacitor enough to summize its lifetime, though.

 

[Dave_H]

+1

Either because they're mechanically weak, using NiMH batteries for storage (not ideal in such application) or even lithium coin cells(!!) and/or crappy way of driving the LEDs - usually direct drive.

I've had several cheapies apart and found one used a Lithium-Ion
coin cell I didn't know existed up to then: LIR2032.

Another one had gear grease with a strong chemical smell I
would not want to breathe for very long.

Another cheated by having two CR2032s cut in when the crank-
charged capacitor was flat; maybe not a bad idea but defeats the
purpose somewhat.

I got a nice one that was sold in Costco in Canada in pairs, forgot
the brand name but they claim are waterproof. Crank action is nice
and doesn't make the horrific grinding sound some do. Five minutes
of crank gave about 20 minutes light to a 1W LED. Zellers in Canada had
them discounted as low as $5/pair last year; they may still have some
at $10/pair. Battery is a flat/round single cell, looks like LI but it's
sealed and hard to get a good look at.

My favourite keychain cranker is smaller than a small box of matches,
two 3mm LEDs, and a LI coin cell 10095 which is smaller than a dime.
(10mm dia., 0.95mm thick). I sometimes joke that it's an austerity
measure due to not being able to afford a bigger one; but it works
OK for what it is, just don't know how long it will hold up.

NiMHs would not be bad if only they would use LSD types (and
maybe some do). I have a solar pocket light with three NiMH 80mAh
button cells, and it seems to hold a charge at least over days to
weeks. This one's easy to maintain though, just leaving it in the sun.

Dave

 

[Locoboy5150]

Capacitors are used in my G scale (LGB only) electric model locomotive sound units. They provide enough power to the units even when the locomotives are running very slowly with very low DC power (around 3 or 4 volts) to the track. They also let the units make idling steam locomotive sounds when no power (0 volts) is in the track and my locomotives are stopped at a station.

I have been using the same capacitors in the same sound units for about 10 years now and they have not shown any signs of diminishing power output. Other model railroaders have told me that theoretically the capacitors won't last forever, but they had not heard of or experienced it themselves.

Train sound units don't have the same big current draw as a flashlight though so I don't know if anything can be drawn from this in terms of if capacitors last a long time. ...just my 2 cents, which after taxes isn't worth much at all.

 

[Dave_H]

I guess I'm a bit skeptical of any clear-cut advantage of a
super-cap flashlight versus a similar size/weight of one using
a LI cell. Capacity of a supercap is way less than same size of LI
and its discharge curve isn't anything close to flat, which rules
out direct-drive (which can be efficient, simple and not a bad
thing). The supercap large number of cycles probably won't be
nearly used up in most cases as the light will mechanically
break, get lost, or discarded well before that.

Supercaps have their uses but any sort of serious flashlight
doesn't strike me as a strong one.

Dave

 

[gswitter]

I'm hoping this will be a good SHTF, last resort light. Until they come out with an appropriate solar charger, Li-ion's are worthless in that regard. Even with the appropriate charge, will Li-ions last for as many cycles as a capacitor (super or otherwise)?

 

[Dave_H]

I got a nice one that was sold in Costco in Canada in pairs, forgot
the brand name but they claim are waterproof. Crank action is nice
and doesn't make the horrific grinding sound some do. Five minutes
of crank gave about 20 minutes light to a 1W LED. Zellers in Canada had
them discounted as low as $5/pair last year; they may still have some
at $10/pair. Battery is a flat/round single cell, looks like LI but it's
sealed and hard to get a good look at.

Dave

The brand name is Sea-Doo, like the personal watercraft. It came on
a big card, typical of Costco (over) packaging.I don't know who
actually makes it, will find out if I can locate that big piece of
cardboard...

I did find one annoying anomoly with this one. When the light got
near the end of charge, electronic on/off switch logic didn't function.
The light stayed on, which meant it would run down whatever charge
was left. I just gave it a few cranks to get the voltage back up, and the
switch worked.

Dave

 

[Dave_H]

I'm hoping this will be a good SHTF, last resort light. Until they come out with an appropriate solar charger, Li-ion's are worthless in that regard. Even with the appropriate charge, will Li-ions last for as many cycles as a capacitor (super or otherwise)?

No, the LI's should last several hundred charge-discharge cycles, maybe a
thousand, who knows, and LI's do have a finite lifetime. I don't know much
about supercaps but surely they can take 10's to 100's of thousands of cycles.
But I repeat, you are going to get so much less capacity with a supercap
for the same size, so unless you want a really big one to compensate
(which dosn't account for the discharge curve issue), a LI is cheap,
better capacity, maybe replaceable. There is no issue with LI's holding a
charge for months. Seriously, how many charge/discharge cycles will the
flashlight really see?

I just picked up a solar-charged flashlight with three pivot-out panels each
with active area the size of a playing card, which has a 3.7v/700mAh LI inside.
They claim 35 hours for 1 LED on, which is reasonable for a 5mm LED (one
or three on modes). The going price used to be $15-20. but it was being
cleared locally.

Dave

 

[Photon]

Capacitor crank light vs. capacitor shake light

Some people have asked me to compare the capacitor crank light to a capacitor shake light since I have both.

Last night I finally dug out my capacitor shake lights Light 1 and Light 2.

These lights had been in storage for more than two years. They were completely discharged; not even the faintest glow from the LED. Both took a lot of shaking (2 minutes +) to get a decent amount of light. Once they were shining, they both dropped off about the same rate as I remember from when I was using them originally. I'm guessing the light decay time constant is on the order of a few minutes.

Light 2 has a clear housing, so I could see the capacitor ratings: 1.5 F at 5.5 V.

Both Light 1 and Light 2 use lenses to concentrate the light output. It will illuminate a spot about 2 feet in diameter several feet in front. This to me is a good compromise between throw and spill.

Light 2 has a noticeable green tint. When I was first using it, I thought it had a cyan LED. As I used it more I realized that it was probably a white LED that has a green tint. I could still discern different colors when using the light in a dark environment.

Light 1 had a noticeable blue tint, primarily in the center of the beam. There are numerous artifacts in the beam (when viewed against a white wall), but in general use they were not a factor.

Both Light 1 and Light 2 would have been suitable for walking a path in pitch black night.

Then I fired up the crank light. After having just shaken the other two lights (with extra shaking for the completely discharged capacitors), I determined that it is easier to crank than to shake. It seems like less effort goes to making more light. The crank light was putting out more light, and I think its time constant was a little longer.

Of course, these are all my impressions and highly subjective.

Conclusions:

(1) Even a completely discharged capacitor (over 2 years) can be recharged without any noticeable effects. It just takes extra shake/crank time to build the charge to where the light output is sufficient.

(2) The shake lights are extremely well made and durable. And they are completely sealed. Even the switch is magnetic so the housing is impervious to water intrusion.

(3) The crank is noticeably easier to work than shaking. It is a newer product with more advanced LEDs and possibly a larger capacitor. It outthrows, outspills and outlasts the shake lights. It is claimed to be water resistant. I have little doubt that it would stand up to some rain.


One of these days I'm going to get a digital camera with manual exposure capability and a time-lapse feature. Then I'll fire up all three of these lights against a wall and post a video showing the beams and their decay characteristics.

Until then, if you want a hiking-in-the-dark light, I'd say go with the crank. If you want to keep a light in a remote cabin, then consider either the shake or crank. If you want an emergency light in the back of your truck, go with the shake.

Others have pointed out that for an emergency light for your car or truck, any old LED light with a lithium battery is a good choice. I'd have to agree with that. But for absolute reliability in any climate at any time, the shake light will be hard to beat.

 

[Apollo Cree]

Generalizations on electrolytic capacitors. If not abused, they will degrade over a period of decades. Think 20 to 30 years or more. Sitting idle for a few years doesn't seem to make much difference. Overvoltage, overcurrent, or heat will reduce lifetime. Reverse charge is quickly fatal. Sometimes they degrade earlier.

This is for "normal" electrolytic capacitors. Supercapacitors are a more recent innovation and may have somewhat different characteristics. The "original" supercapcitors had some secret techniques to make them work right. There were some other manufactures who tried to copy the design and didn't know the right type and quantity of batwings and eye of newt to add. The result was that the clone supercaps worked great but failed after a few years. Many computer manufacturers had to replace a lot of motherboards after a few years.

You don't hear a lot about supercaps failing these days. I assume the cloners either quit making the caps or found out the right magic ingredients to add. Supercaps are more fragile than normal electrolytic caps.

 

[Fallingwater]

The main problem with crank lights isn't the battery (though that can sometimes cause problems too), it's the mechanical works of the generator. All crank lights I've seen so far have supercheap gears made of plastic that can't possibly stand up to years of use. Another source of problems might be the cheap brushed motors they use as generators, but then I think the gears or battery would give up the ghost a long time before the brushes wear out.

If this one has gears made of a sturdier material and a proper generator instead of the usual brushed motor, then it might be a good product. Otherwise, merely using a capacitor won't really make much of a difference, IMO.

 

[Apollo Cree]

The main problem with crank lights isn't the battery (though that can sometimes cause problems too), it's the mechanical works of the generator. All crank lights I've seen so far have supercheap gears made of plastic that can't possibly stand up to years of use. Another source of problems might be the cheap brushed motors they use as generators, but then I think the gears or battery would give up the ghost a long time before the brushes wear out.

If this one has gears made of a sturdier material and a proper generator instead of the usual brushed motor, then it might be a good product. Otherwise, merely using a capacitor won't really make much of a difference, IMO.

I've seen several cranklights from different manufacturers that now light up while you crank but go dim almost immediately after you stop cranking. Sounds like bad batteries to me.

Occasionally, I'll have one that you have to crank an extra long time, but after that it will eventually start holding a charge again.

Sitting without being cranked for a while or simple old age seems to be the trigger.

 

[ama230]

I am a EE with experience with ultracaps and the sort...

A battery no matter what the chemistry is going to degrade over time no matter if you charge or discharge but with their present day characteristics they perform better with active charging/discharging. Think of it as exercise, this keeps the body's chemistry sharp and functioning to its max potential.

Of course they say that a battery is cheaper and performs better but that has had alot attention payed towards it since it drives everyday devices that are power hungry and very inefficient, heat and noise being the culprits. If an efficient driver were applied to a battery it still is loosing some of the power charging it(wasted heat and limited current to not damage the cell). So basically the cell is only seeing 50-60 percent of the charge coming in, thus the remaining percentage could not be harnessed. Then there is only 1000max cycles(1 charge/discharge= 1 cycle) in the best battery today and that is it. This breaks down to roughly 3-5years nominal useage. So at 100years of human these days would cost 1$ every 3 years for a AA. This would cost roughly 35$ at todays prices which is pretty good but that is over 30lbs of non recyclable waste that is highly toxic.

Then there is the opposite side that is the ultracap. The way that these things work is a thin piece of tightly wound aluminum with a porous carbon substrate in the middle to act a sponge. The the remaining filler area has an electrolyte to allow for conduction through the device. Remind you guys that these are not a battery of any sort since they DO NOT rely on a chemical reaction to store a charge so power density suffers but it gives it awesome life. If a string of electrons is thrown through the device it then captures all but +/- 5% of the electrons in the carbon and just holds them there, there is no advanced chemistry its just the characteristics of the carbon(like in carbon nano tubes). Of course they will not hold their electrons very good but its good for about three months and you have about half the electrons available. Then the upside is that the electrons are willing to travel at any given time with a appropriate load(higher than the cap itself).

I have a 2d maglite that I modified to hold two 350F ultracaps and wired them in series since it was just easier then applied a charging jack(3.5mm audio jack) at the bottom in the cap. Then put an efficient 1/2 watt led(white/blue) that gives roughly 40lumens -50lumens and throws it along ways with the stock reflector. Mind you that this thing is almost older than me(my dad bought it in 88 i think) and was easily able to convert it with little effort. All of the functions still work like focusing and push button but has an added perk of being able to run and charge at the same time which is pretty cool. Also a little more information on cap vs battery is that a 350F cap has the energy density of a 1000mah aaa battery but can charge ,run more efficiently and life is longer than you and me!!!:nana: Let me say that they can also be thrown in the trash when 100 years has passed with no worries. So an initial cost of 20 bucks for two 350F cells will last longer, save more energy, and not to mention save more money. Try something new, you could make the next breakthrough with slapping a couple of old conventional devices together and updating the power supply(ultracaps). This flashlight will put out eight hours of useable light and still keeps running. There is no advance circuitry that needs to charge these things. Just keep it under the 2.5V or 2.7V that cell calls for and you're set. You can deliver a 100Amps(really fast) or just 200mA(slow,its just going to take longer to charge). Any cheap dc charger or wall charger will do. Mine charges in 4 minutes with 6v@200mA and lasts for eight plus hours. This is no joke anybody these are not false claims...I promise you that. The only downside is that when you order quality ultracaps form tecate group you have a minimum order and I got mine for 60 bucks shipped for four but you can them cheaper elsewhere but have to have awesome networking skills(the equivalent to god basically). So the cost of the home and car chargers were 12 bucks at frys and 1 buck for connectors and 7 bucks for the regulator and led. The flashlight was free but costed 20 bucks years ago. Then this thing will last longer than me and never needs to be opened again, just the replacement of the led after 10years or so which is just crazy as i haven't heard of anybody needing to replace an led before because it wore out.
These thing are safer than batteries and you cannot short them out since they will fry the wire or anything in its path before catching fire so the cell basically remains undamaged. Im saying that if you take a 10ga wire and stick it to the leads it will arc as it is repelling the wire and turn it to dust so there is no actual contact to the cell, its quite awesome and i recommend it to anybody, just wear safety glasses that are tinted!!!

Any questions or comment welcomed. Hope this helps....

 

[ama230]

I am a EE with experience with ultracaps and the sort...

A battery no matter what the chemistry is going to degrade over time no matter if you charge or discharge but with their present day characteristics they perform better with active charging/discharging. Think of it as exercise, this keeps the body's chemistry sharp and functioning to its max potential.

Of course they say that a battery is cheaper and performs better but that has had alot attention payed towards it since it drives everyday devices that are power hungry and very inefficient, heat and noise being the culprits. If an efficient driver were applied to a battery it still is loosing some of the power charging it(wasted heat and limited current to not damage the cell). So basically the cell is only seeing 50-60 percent of the charge coming in, thus the remaining percentage could not be harnessed. Then there is only 1000max cycles(1 charge/discharge= 1 cycle) in the best battery today and that is it. This breaks down to roughly 3-5years nominal useage. So at 100years of human these days would cost 1$ every 3 years for a AA. This would cost roughly 35$ at todays prices which is pretty good but that is over 30lbs of non recyclable waste that is highly toxic.

Then there is the opposite side that is the ultracap. The way that these things work is a thin piece of tightly wound aluminum with a porous carbon substrate in the middle to act a sponge. The the remaining filler area has an electrolyte to allow for conduction through the device. Remind you guys that these are not a battery of any sort since they DO NOT rely on a chemical reaction to store a charge so power density suffers but it gives it awesome life. If a string of electrons is thrown through the device it then captures all but +/- 5% of the electrons in the carbon and just holds them there, there is no advanced chemistry its just the characteristics of the carbon(like in carbon nano tubes). Of course they will not hold their electrons very good but its good for about three months and you have about half the electrons available. Then the upside is that the electrons are willing to travel at any given time with a appropriate load(higher than the cap itself).

I have a 2d maglite that I modified to hold two 350F ultracaps and wired them in series since it was just easier then applied a charging jack(3.5mm audio jack) at the bottom in the cap. Then put an efficient 1/2 watt led(white/blue) that gives roughly 40lumens -50lumens and throws it along ways with the stock reflector. Mind you that this thing is almost older than me(my dad bought it in 88 i think) and was easily able to convert it with little effort. All of the functions still work like focusing and push button but has an added perk of being able to run and charge at the same time which is pretty cool. Also a little more information on cap vs battery is that a 350F cap has the energy density of a 1000mah aaa battery but can charge ,run more efficiently and life is longer than you and me!!!:nana: Let me say that they can also be thrown in the trash when 100 years has passed with no worries. So an initial cost of 20 bucks for two 350F cells will last longer, save more energy, and not to mention save more money. Try something new, you could make the next breakthrough with slapping a couple of old conventional devices together and updating the power supply(ultracaps). This flashlight will put out eight hours of useable light and still keeps running. There is no advance circuitry that needs to charge these things. Just keep it under the 2.5V or 2.7V that cell calls for and you're set. You can deliver a 100Amps(really fast) or just 200mA(slow,its just going to take longer to charge). Any cheap dc charger or wall charger will do. Mine charges in 4 minutes with 6v@200mA and lasts for eight plus hours. This is no joke anybody these are not false claims...I promise you that. The only downside is that when you order quality ultracaps form tecate group you have a minimum order and I got mine for 60 bucks shipped for four but you can them cheaper elsewhere but have to have awesome networking skills(the equivalent to god basically). So the cost of the home and car chargers were 12 bucks at frys and 1 buck for connectors and 7 bucks for the regulator and led. The flashlight was free but costed 20 bucks years ago. Then this thing will last longer than me and never needs to be opened again, just the replacement of the led after 10years or so which is just crazy as i haven't heard of anybody needing to replace an led before because it wore out.
These thing are safer than batteries and you cannot short them out since they will fry the wire or anything in its path before catching fire so the cell basically remains undamaged. Im saying that if you take a 10ga wire and stick it to the leads it will arc as it is repelling the wire and turn it to dust so there is no actual contact to the cell, its quite awesome and i recommend it to anybody, just wear safety glasses that are tinted!!!

Any questions or comment welcomed. Hope this helps....

 

[filibuster]

ama230, where do you get a regulator for a capacitor that will use the capacitors full capacity? Or is there a practical limit to the amount of power you can draw out of the capacitor at lower voltages?