Can VAN DE GRAAFFF Be Used to Charge Batteries?

Not reasonably.

..." A tabletop Van de Graaff machine supplies a watt or two of electrical energy. For example, a small VDG machine which produces 250,000 volts at 10 microamps would act as a 2.5 watt DC power supply. "...

It might be possible, but not practical...

http://amasci.com/emotor/vdgdesc.html#step

Here's a 20 watt pedal charger, not really practical except maybe in an emergency...

This is much more practical, and affordable...

Take apart one of these. See if this helps!

A1) Impractical. The source is high impedance and a lead-acid battery is low impedance; there are better ways of accomplishing the task.

A2) -

A3) This is the usual method.

A4) -

1. To me it now appears that Large voltages are developed in Van De Graff generators, but currents are small.
2. It is possible to charge lead acid battery through power electronics (which is anyway common) by VDGG but may appear to be no practical as alternatives are available.
3. I am actually trying to revive VDGG as an alternative to existing alternatives ,particularly Solar PV (India is heavily dependent on imports for Solar PV- which makes it expensive). Moreover silicon will never be made in India and Rupee keeps degrading against US Dollar.
4. Hence i wish to look for alternatives anyway.

A1) Correct.

A2) Quite.

A3) Abstruse.

A4) Good luck with that.

To convert mechanical energy into electrical energy requires a great deal of work when speaking in terms of human manual labor...

Using a bicycle converted to turn a car alternator/generator to charge this battery would take all day, and hard to pedal as well....you would need about 20 people in good shape....there are much easier ways....

I built one, and at 62 years of age, can charge up the battery just enough to start my wife's car after hers sits in the garage too long. Note, it does give me rubber leg syndrome, and I am no good for mowing after this.

Or a few good pro cyclists who can average 245W/hr for a 6 hour tour stage for 21 days of 23 days. Have to have a couple of rest days in there. The domestics are probably the lowest payed professional athletes, so you may be able to afford them for a while.

Why, it isn't a practical alternative. About the cheapest would be a simple alternator connected to an old bicycle on a cheap stand with an inexpensive battery charger circuit.

Only problem is that you would have to peddle for hours to charge up a decent sized lead acid battery.

Smaller devices like radios and lamps can be obtained or built fairly cheaply that work on windup or shake charging systems.

Again why, a VDGG is simply a high voltage static generator, it isn't a real source of usable power (like trying to store the electricity created by electrostatic discharge). There just isn't enough current generated to make it practical compared to all the alternatives, even if price were taken into consideration.

You would have better luck with a homopolar generator, low voltage, high current. You might have to have lots of Indian citizens pedaling these, with their wires connected in series/ parallel arrangement to charge up a large battery bank.

On the other hand, learn to make hydrogen from water and heat, and ?? electricity, and generate more electricity, from which to make more hydrogen etc.

On the other hand, learn to make hydrogen from water and heat, and ?? electricity, and generate more electricity, from which to make more hydrogen etc.

Seriously?

Please remember to post an appropriate emoticon least people new to the site reading your comment think this is a good idea and we start getting the old water electrolysis pseudoscience questions again. Alternatively just don't mention it.

I was thinking that the mere mentioning of a cyclic reference would be enough discouragement from that. Now, if they had good hydrogen generators, and some good high amperage DC, they could make hydrogen, store it at some pressure, and then use it in fuel cells later and come out winners, but they have to be able to buy the crackers to have with the cheese, after they buy the cheese for cheese and crackers.

I was thinking that the mere mentioning of a cyclic reference would be enough discouragement from that.

That's what emoticons are for, even then all common sense on the part of the reader can be lost if they are told something will work when it won't, especially if they go looking for it online where most of the links are to convincing looking pseudoscience scams and poorly implemented backyard scientific experiments.

Hey, if they want to use a lower power intensity device to make hydrogen (for a long time), and supposing they could store it up in a bottle (cylinder), and then further suppose they could run an ICE or a small micro gas turbine off it later, and turn a real generator, then they would have an intermittent source. Power in < Power out, but Energy in > Energy out, don't ever forget that, even for a moment.

The amount of current generated by a VanDeGraaff generator running continuously would take over 100 years to charge a 10 AH lead acid battery.

How about collecting the charge from the VDGG as high voltage DC on a superlarge audio capacitor (1 F is now available for small price on Alibaba), then use a chopper/transformer to convert it to AC, then down convert the voltage to supply more current. It is not the HVDC current that matters, it is the total energy stored.

Unfortunately due to the high self discharge characteristics of these fairly inexpensive capacitors I think you will find that you will lose as much power as you put in, to mention nothing of the combined losses of all the voltage conversion electronics.

Assuming a theoretical ideal 100% conversion and storage efficiency you would still be waiting a loooooooong time (hours or more for example) to store up a meaningful charge that may give you a few seconds of useful power to power a LED light (for example).

A hand cranked generator makes much more sense than a hand cranked Van De Graff generator as a power source.

Yep there are better cheaper ways for this to happen.

Check the voltage rating on the 1F capacitors. They're generally about 2-3 volts. Your VDGG voltage would zap through them in an instant.

The van De Graaff machine acts as a high voltage capacitor, storing the charge. But switching voltages that high is problematic. (How do you switch voltage that jumps inches through the air?)

Assuming you could switch the high voltage, possibly you could use a Tesla coil transformer in reverse and rectify the output.

The efficiency with the above scheme, I am sure, would be very low. A simple DC generator is close to 90+ percent efficient at converting mechanical energy to electrical.

In electrical engineering terms, there is a huge impedance mismatch between a VDGG (high voltage, low current) and a battery (low voltage, high current), and matching these together is an inefficient process.

Wow, that trial balloon didn't go very far at all. Thanks for information about the V limit of the audio capacitors. There are machines that exist for converting HVDC to 3 PH MVAC, etc. since ABB apparently joined the business of medium class power conversion.

This is still far too expensive for what OP wants to do. Basically, there is no road from where he is to the destination. The better answers have already been given.

Either learn to do solar thermal (CSP), or photovoltaic, since apparently not much wind where he is.

The wet and humid air over India for most of the year would preclude any chance of success.

As others have said the wattage of a VDG source is at a very high voltage and in micro amps

Developing a switching power supply to convert that to 12 volts at 200 ma(2.4 watts) would be hard, costly and would use up half of this wattage.

Now an organic solution, such as stroking cats or sacred cows, would simplify things, but again would suffer humidity problems in certain seasons. In addition, can you imagine a cat strapped into a harness with a mechanical stroking machine....unless you are up 'fur' that task...

OK now we're getting someplace....

If this has devolved into "cat" generators (not Catepillar, but Feline cats)...

https://www.youtube.com/watch?v=jk3xBhqcjqY

That one is absolutely the most brilliant idea I have seen in a long, long time. Now where is that cat, and took my buttered toast?

Plant a lemon tree.

He he! This whole thread is a lemon anyway.

You would get more energy stored on your capacitor by forgetting the VDGG, losing it in the woods, then just making a really high antenna, and collecting the static electricity when the wind blows. In fact, if you design your charge collectors just right, you will be able to hear the ocean from the Himalayas. I think something like moth scales texture interlocking on highly insulating plastic like PE would be a good start, you could also make a spiral airfoil out of the plastic, and turn an alternator with that. Anyone tampering with the wires (like my cat did) from the alternator to the battery will receive their just punishment and shaming. They will also be identified by the wet area between their legs. Your best bet. Plug a battery charger into an electric power outlet where there is power, charge up the battery, put the battery on the bicycle, pedal up the mountain. Tell the guru that next time, he gets to pedal the bike back home.

As you now know from many posts, your idea is impractical.

I thought that you idea was similar to pulling a caravan behind a F1 racing car, totally unbalanced technology I mean....

Is there something that you have not mentioned as to why you wanted to do this?

Furthermore, the usage of lead acid battery makes the idea even worse as they are one of the least efficient storage batteries around. There is an area of charge (from memory) that allows a sweet spot of around 70%, but usually less, so you will be wasting probably half of any energy produced!

I recently found this paper that provided some really interesting observations of charge and lead aid batteries, though it appears that only one type/manufacturer's batteries were used if I remember correctly:-

Lead_Acid_Battery_Efficiency.pdf

I hope this helps.

I am an engineer, not a scientist. I was talking to post doctoral experts who are working on futuristic batteries. My suggestion was - to design a battery where +ve and -ve charges can be generated within the battery without an external power source. So it can be charged while it is also connected to load. Charging should not take hours. Pl look for a concept http://contest.techbriefs.com/2016/entries/consumer-products/6672

Now you will understand linkage between these discussions on Van De Graff generator, previous discussions on how rain clouds get charged etc etc.

"Pleasure in the job put perfection in the work." -- Aristotle

The only way to do this is to remove the battery chemicals that have changed state to an external place to change their state and return.

This is what flow batteries do and they are candidates for fast recharge analogs of gasoline engines.

Read about them here, work proceeds, perhaps some day = prime time in cars

Aurizon: So far, flow batteries take up a large amount of space, you can Google search the largest flow battery and see for yourself the energy storage capacity in MWh, and the power in MW, or kVA, either one.

I have heard of attempts to come up with this for automobiles.

I would like to see an Aluminum cell for this (similar to Li+, but three times the charge on Al3+ ion, and also the Stanford University battery of this type was recharged quickly compared to Li+, did deposit aluminum metal on the anode of the battery, and also employed Al3+ ion charge storage similar to Li+, thus the power density is very favorable, and the weight is also favorable.

One could make an analog to a flow battery on the aluminum battery, by (1) pulling out the "spent" anodes and swapping them with ones with fresh aluminum deposits, draining the electrolyte, and recharging with fresh electrolyte, maybe.

Better yet would be just have an interlock system that releases the battery from under the car, car rolls forward to next slot in exchange bay, and takes on freshly charged battery bank, and leaves. Tracking, payment, etc. all done wirelessly. Since the aluminum battery can be charged much more rapidly than Li+, and has better characteristics for the power demand, and can sustain at least 10 times the cycling of Li+ with no fire hazard, I fail to see why Li+ still could have any place in future automotive applications.

Aluminium batteries are primary or one time batteries. The recharge process of turning the Al2O3 in Aluminium again is extremely energy intensive. This reaction is not operated in a reversible manner, so the energy gaing from the use of the aluminium battery is probably only about 20-25% of the cost of new metal, since the Hall process is in molten salt.

As said in the original link, they are not ready for prime time yet in cars, but get better over time.

With an added lithium battery for current a system with a flow battery that charged the Lithium might be workable, it depends on speed and amount of acceleration being done. With a flow battery you would fill up with charged battery fluid and leave discharged battery fluid at the station - a relatively fast process. Measurement of the charge level and volume of discharged fluid versus the volume of charged fluid = the fee.

These might better suite long haul trucker use?

Apparently, you did not read what I wrote or check into the research published last year on Aluminum battery.

Yes, the old Aluminum-air battery is a one shot device. NO, the new one is completely rechargeable (in spite of what you think), and can be recharged exceedingly many more times than Li+ battery, and can be discharged deeply each cycle without significant loss of capacity. You really do not understand when you are still thinking Hall-Heroult process: https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_process

The new Aluminum battery: https://en.wikipedia.org/wiki/Aluminium-ion_battery

This battery was developed at Stanford University. Wake up and smell the coffee.

I do not see any battery technology that will ever beat diesel for Ice Road Truckers any time soon, or ever.

A truck with a small nuclear reactor might work, however. This will be brought online by Skunk Works maybe in the next four years. They will work for some planes, and also for tanks.

You will never catch me smelling coffee. Yes that aluminium ion battery looks encouraging indeed as it offers full rechargeability.

Tesla and other potential battery users should have their nose to that grind stone.

Even so, Lithium is where it is now after 20 years of intense research, what will the pace of advance of Al-ion?

With all the knowledge gained from the Li+ battery, and the current state of development of battery fabrication. I think they should have commercially viable Aluminum/Aluminum ion batteries before Obama leaves office (you watch, he will probably declare himself dicktater for life.

I have tried to understand battery operation better- theyε are not capacitors and do not follow C= εo εr*A/d. Hence they all involve chemical reaction. As discussed about Aluminum electrode batteries, these are irreversible (within the battery, may Al could be recovered outside). My own proposal is there will be a +ve and a -ve electrode- anyway. The current passes through the same electrolyte either for charging or discharging in opposite direction. If for arithmetical discussion, electrolyte had low resistance- charges on the electrode plates would cancel out. Hence the electrolyte or any medium between the electrodes has to be insulating- but it should be conducting for discharging so that internal resistance of the battery is low.

1. Hence any medium between the electrode has to have diode like behavior
2. Electrodes must be high charge density material type.
3. I still dot know whether I am looking for a battery or a ultra ultra super capacitor so it is reusable, does not have chemicals which looses its property after usage (hence that battery is not rechargeable). Flow battery in present form are not suitable for vehicles.

These are just passing thoughts on a futuristic battery.

"Let me tell you the secret that has led me to my goal: my strength lies solely in my tenacity." -- Louis Pasteur

"If you don't know where you're going, then any direction will do." -- Lewis Carroll

"ABILITY is what you are capable of doing. MOTIVATION determines what you do. ATTITUDE determines how well you do it." -- Lou Holtz

"The greater the obstacle, the more glory in overcoming it." -- David Hume

Thanks CR4- I love those quotes below.

Basically after reading what you wrote, I have a word for your thought process on batteries: WRONG!

Go back and read college general chemistry text, especially the chapter about the Danielle cell, the Galvanic cell, electrochemical potential, the relationship between Gibbs free energy and electric cell potential, etc.

Then look at the works of Tafel to understand something about the voltage-current relationships of electrochemical cells. Bokris is another good author who has a lot to say about electrochemistry.

I did not log in when I commented at 36. Do note I have stated that batteries are different and capacitors have a different formula for energy storage. Batteries have a chemical reaction Flow battery was discussed to take out electrolyte and pour back after charging. But this to has draw backs.

This is how I started searching for a new source (conceptual now) and looked at rain clouds getting charged. Then came Van De Graff generator. So it has been a logical flow. To look for a futuristic battery which need not be chemical etc etc

There have been many vehicular energy storage proposals over the years. Assorted batteries and internal combustion(IC) of various materials have been the most successful. Capacitors and springs have been the least - until now - Van de Graf generators are mechanical charge pumps that have a vanishingly small amount of power, with a paradoxically high potential(voltage) is now the least capable method of powering vehicles.

It is good to be open minded about potential new power, but one should assess them with dispassion and accuracy.

They have done a good job at using high speed flywheels, in a vacuum at 500,000 rpm or more, using epoxy glued carbon fiber rotors

These have worked in some applications on level ground, with proper mounts to obviate precessionary forces, but are not yet ready for prime time.

I have looked into the aluminium ion batteries and they will have an impact in the field in about 4-5 years, if scaling and fabrication aspects are solved, because they can be far cheaper, due to lower cost of common aluminium and the presence of 3 electron transfers (albeit at only 2 volts versus 3.7 for Lithium - which has only a single electron transfer) - thus aluminium should win - unless some intractable problem emerges??

I can see a future for flow batteries, based on Vanadium as well, due to the fact that they refuel as quickly as gasoline tanks, although they need two hoses, one to fill the charged liquid flow tank and the other to empty the discharged fluid flow tank. The lack of flammability of these aqueous fluids will ease these transfers.

I get what you are saying about flow batteries. There is one great big show stopper, however. Range.

Or tank size. You can't have range and still have a 20 gallon tank. The energy density of prepared electrolyte/reagent is just not high at all compared to liquid transportable fuels, including liquid methane, and liquid hydrogen, or even compressed hydrogen.

Yes, the energy density is lower than combustable which use air and make CO2, one hopes rising costs for burning good organics to polute the air will gradually be curbed.

I am not sure where the fluid energy density of flow batteries will reach, but it will be lower than combustables, however, the efficiency and lesser motor weight might compensate. They will most likely be used with an accompanying lithium battery to provide traction on start, etc, to reduce the dimensions of the flow cell - which dimensions are decreasing, but are still objectionable.

Unlike magnetic poles, +ve and -ve charges can remain in isolation- meaning we can have a plate which is only +vely charged or only -vely charged. Both need not be in equal proportion. Given that what happens if we bring a highly +vely charged plate and a highly -vely charged plate together (they were charged separately earlier. The electrode itself can be Aluminum- with 3 electrons - if our friends prefers that over Lithium. I found charge density is number of electrons per volume of atom. Magnesium has higher density though it can release only one electron as its atom size is small). Chemical technologists feel charges are created in electrolyte, but reside on electrodes. If so, ca we find other ways of generating charges without electrolyte? Anyway we need high density electrodes only !!!!

Wow! You really do not understand. Magnesium is not univalent, it is divalent. Go read a chemistry book. I don't care what chemical "technologists" think, they do not have a suitable level of education. Degreed chemist or chemical engineer would never, ever say what you said, and certainly not in the way you said it.

You have 0% chance of success with your project, unless you stop spouting nonsense, go read some entry level books, and get some sort of base to stand on. Then you can experiment. Right now you have 0% chance of understanding what you are doing, or why it does not work.

You also need to use both ears twice as much as your mouth (speaking in terms of responses). Read, try to understand, listen to what is being said as advice, ask questions about what you do not understand, then you should think about and write a two minute outline of what your response on the blog will be. Right now, you are totally wasting your time.

See https://en.wikipedia.org/wiki/Magnesium_battery

Magnesium secondary cell batteries are an active research topic, specifically as an alternative to lithium ion based battery chemistries. A solid magnesium anode allows a higher volumetric energy density than lithium, carrying two electrons per ion, display a volumetric capacity of 3833 mAh cm^-3 vs. 2036 mAh cm^-3 for Li metal,^[1] although its energy density per unit mass is under half that of lithium (18.8 MJ/kg vs. 42.3 MJ/kg).^{[note 1][note 2]} In comparison to metallic lithium anodes, magnesium anodes have not exhibiteddendrite formation during charging,^[2] which may allow magnesium metal to be used without an intercalation compound at the anode;^{[note 3]} eliminating the intercalation layer raises the theoretical maximum relative volumetric energy density to around 5 times that of a lithium ion cell.^[4] Magnesium batteries may have a cost advantage over lithium due to the abundance of magnesium on earth.^[2]

Nice cut and paste job. I have made batteries of a completely different type using magnesium, copper, and some solid phase media (easy to buy crystalline salts mostly), and it is odd, but magnesium combination puts out more volts (1.5-1.7 V new), and far more current for this type than its aluminum counterpart.

They are called phonon cells, in which insulating (normally) materials behave almost as semiconductors as charge transport media, just at quite a bit lower flux density of charge carriers. Phonons (thermal vibration modes) in the crystals result in band overlap between different crystal types such that valence band electrons of one crystal type may have a suitable Fermi level and excitation to transfer an electron (or proton if available) to/from another crystal whose conduction band is an energy match. The metal pair is polarizing the cell to the extent of the galvanic potential of the pair for the conditions in the media. Crystals with hydrate structure seem to work best thus far. Under some conditions, mainly where the temperature is high enough to melt/dissolve the media in its own water, the cell operates essentially as a galvanic cell, with the more active metal "corroding" away. They are not rechargeable in the sense that applied potential will restore the cell, however, as long as the anode metal remains, the cell will have output very similar to day one.

Under loads, I have made cells with output resistance as low as 3 Ohms thus far, but the output resistance is a strong function of temperature, and obviously contact area. No light sensitivity was obtained in early attempts to incorporate lead perovskite type structures, however, it is noted that all solar perovskite minerals known thus far are moisture sensitive...

Nice to see your science background and your passion to develop new batteries.

As an engineer- the way I see the problem (of long charging times of existing batteries and electrodes getting eroded etc) is different. Hence- I told my post doctoral science colleagues who are working on flow batteries- that we need to redefine the problem. In India we have different working approach - try to reinvent the wheel using tax payer's money. I feel saddened to see money spent, papers published, but all purely academic.

That is how I started the previous thread- about rain clouds getting charged - without a source of electricity. In India- even solar panels are imported and so I am concerned with Dollar outflow. Solution you may find, may be or may not be suitable to Indian conditions.

So my search is still on.

10 of the Magnesium plates, 30.48 cm each side, by 6.35 mm thickness (12" x 12" x 0.25") cost about $400-$500 depending on where you get them. Not cheap by any standard.

I will be working on plating copper (extremely uniformly with no vacations, pinholes, etc.) onto one side of the magnesium plate. A stack of 10 plates should yield a voltage of 17.3-17.8 volts when the correct crystal matrix is added. I expect something like 15-30 Ohm output resistance, at 70-90 °C.

If there is not much wind, have you considered using a wind turbine of very large cross-sectional area (use cotton to make sails, etc.)? Or make mud bricks dried in the sun, and build a wind channel to produce a high wind current in one spot, and use triboelectricity, or an efficient small diameter wind turbine to turn a generator.

One can use iron (cast iron plates) and copper for phonon battery, but at much reduced voltage. Iron is relatively easy to smelt from its oxide, so recycling the metal is not as hard as aluminum or magnesium.

WOW great you are actually trying to construct a magnesium based battery. I have given calculation for increasing the wind speed. Note as a thumb rule- wind entering = wind leaving. No storage. Given that when wind is captured by a huge funnel with an opening of say 2.5 meters and is let out through a opening as small as 25 cm ratio of diameters is 10 times. So wind speeds will increase by (10^2)= 100 times!!!!! So 1m/sec wind will be actually rushing out at 200m/sec. That should be enough to create turbulence for tribo-electricity generator.

At link http://contest.techbriefs.com/2016/entries/consumer-products/6672

Saw that. looks interesting, since no moving mechanical parts, but must be made bull stout, pig tight, and horse high.

Thank you so much. You have gone out of the way to procure such expensive magnesium plates. Therefore, I feel it my duty to let you know what I have in my mind when I wrote that on NASA’s web page.

FIG 1 are 2 magnesium plates with copper coating. Considering the dimensions of the plates mentioned by you, even if you keep powerful magnets, the field strength will be low. Wish dimension along NS magnetic field is as small as 6 mm and powerful Samarium or Neodymium magnets are placed.

The outlet area is about 4 times inlet area, so that wind speed would have fallen by about 16 times. Wind speed anyway falls due to turbulence with turboelectric materials on the way out.

When outlet side wind speed is closer to the inlet speed, energy is assumed to have been extracted to the maximum. Magnetic path must be completed externally between N & S poles.

Actually, at this point I have no idea what you are talking about, and I cannot follow what you are trying to communicate. I do not use magnets at all in phonon battery experiments, although it did occur to me to see if magnetic removal of electronic state degeneracy might help with charge carrier transfer.

Are you the one designing this flow system through the copper-coated magnesium plates? Why? How is that any better than just an Aluminum plate? Steel plate?

Too bad funnels don't work that way.

I guess that's why they call it a bottle neck, huh.

The velocity has to speed up anyway, at the neck from the opening, based on applied pressure. What about creating a Bernoulli effect with some venturi nozzles to attempt to gain even more air flow?

I saw recently a horizontal axis wind turbine design that is based on a spiral cone, that seems to be highly efficient.

So, to summarise, it's codswallop.