What do you know about lithium ion battery technology?\nDo you know about the parameters for current and voltage  when charging a lithium ion battery.... What ever you know about creating a circuit that will reduce or cut off the voltage when a lithium cell is fully charged please read my quesition on the Engineering section(Science).  I am not talking about the NiCD and NiMH rechargable batteries.
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http://en.wikipedia.org/wiki/Lithium_ion_battery
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Its using induction charge principle. Essentially the primary coil side of the transformer is built into the base and the secondary coil is built into the toothbrush. \n\nThe primary winding of the inductive charger transmits charging power to the secondary winding, inside the target device, without making direct electrical or mechanical contact with it. In the target device, power is received with a coil and then rectified by a diode. This DC voltage is used in charging the battery of the device.
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"gods_my_ruler" obviously has NO IDEA what he is talking about.\nOf course you can, easily split H2O into H2 and O2 gas through a process known as "electrolysis".  Actually, 12 volts is way over the minimum voltage required to electrolysize water.\nYou will also, of course, need to use some form of electrolyte (commonly, "salt", or Na/K Hydroxide are popular choices) in order to help the water conduct electricity since pure water does will not conduct at all.\n\nBut you question was about controlling the current flow.\nI assume you are having problems with the current getting too high and overloading your power supply?\nFor starters, I would downgrade your power source to something with a little less voltage if possible.\nYou can also use combinations of small (on the order or just a few ohms or less) resistors wired in series/parallel in order to give you just the right resistance you are looking for in order to decrease the current through the cell.\n\nWithout more specifics about the problem you are having, that is about all the advice I can give for now.\n\nRemember, it is not the voltage that controls the H2 production rate, it is the current.\nAccording to Ohm's Law,\nV = R*I\nso a higher voltage (with a given resistance) does mean a higher current, but the same goal could be achieved with a lower voltage and much lower resistance.\n\n\nEDIT:\nIn reply to "kurticus1024",\n\nUsing a reostat or variable resistor would work to dynamically control the resistance in the circuit, and thus the current through the cell, however, most reostat which I am aware of have a high minimum resistance (i.e.  even when turned all the way to the minimum setting, they are far from zero ohms) so by doing this, you will be DRAMATICALLY increasing the resistance through the cell and intern virctually cutting your cuttent to just a few miliamps.  A few miliamps is fine for many common electrical components whcih the reostat was designed for but if you intend on produce Hydrogen, you are going to have to wait a VERY long time to get any sizeable amount.
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You need at least A and B.  B to get a low voltage drop and A to get high current.  I'm not sure what effect C has.  It's been awhile.  \n\nAfter a little more research, C would also apply for the efficiency reason.  So D is your answer.
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In an electrolytic cell you can plate most any metal that doesn't quickly react with the solvent and its solutes.  The force of the copper ions gaining electrons at a negative charged zinc electrode is certainly possible.\n\nSince the copper would receive two electrons and go from a +2 to a zero oxidation state, you would say that it is being reduced.
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Solar or light can be converted into current and batteries can be made at a smaller scale. Example is, small calculators are powered by solar cells.\n\nAs for as construction of those batteries they are made of smaller cells and then smaller cells are joint with other smaller cells to make little large cells. Its very expensive to make them on commercial level thats why we are addicted to oil.\n\nCheap things sometimes don't come cheap.
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Because I'll bet you let it sit all summer without ever using it or charging it, right?\n\nLead-acid batteries have to be regularly discharged and recharged to retain their ability to work.  If you go two or three months just letting a battery sit, it's done for.\n\nAfter you buy your new one this year, and when the season is over, here's what you need to do:  every two weeks (at LEAST), fire up the snowmobile and run it for a while.  Then put the battery on an automated trickle-charger -- if you get one that has a "maintenance mode," so much the better, you can just leave it on all the time, and the charger will maintain the battery for you.\nIf you do the above, your battery will be ready to go the next winter, and will last at least 4-5 years, probably more.
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Lightning basically is a discharge of static electricity. Atmosphere and ground work like two plates of a condensator.\n\nCharging a battery requires a steady current within a limited voltage range - if the voltage range is exceeded, all kinds of unwanted reactions take place which are likely to destroy the battery.\n\nI think what you are after is not use of the lightnings, but something like a cable hanging from the sky through which the electrostatic charge can be neutralized.\n\nThere are a couple of practical difficulties creating and fixating such a cable (or a sufficiently high tower). If we had them, we could indeed leach away potential differences between various layers of the atmosphere and the ground. Several science fiction writers have exploited that idea assuming availability of high temperature superconductors and spacelift cables. It might just work.\n\nSuperconductors are almost a necessity because a conventional cable that long would use up most of the energy as thermal energy released from its electrical resistance.\n\n\nSo: The use of lightnings as energy source is highly unlikely. The use of the energy which causes lightnings is theoretically possible, practically we lack the technology to make it useful. It is unlikely that we would rely on that energy if we could make space-lift cables because in that case we'd simply use solar energy collectors in space and lead down all the energy we need from the vast amount of unused solar radiation.
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Short circuiting the battery is not a good idea, but it should not explode or leak "acid" as you suggest.  It is actually incorrect to call the inner contents of a standard 9 volt batter "acid" since there is actually no "acid" inside.  Most standard batteries are called "alkaline".\n\nThe wire placed acrocess the two leads of the battery has very little resistance...almost zero (but not quite zero, just a tab above).\nAccording to Ohm's law,\nV = R*I\nwhere V is the voltage, R is the resistance, and I is the current, you can see that with a very small resistance, a very large current will be drawn.  This large current will heat up the wire. Depending on just how much current and the type and thickness of the wire, the wire may or may not begin to glow or melt.\nSoon after shorting out the batter (within a few minutes) the battery will be dead.  An aweful waste of a battery in my opinion.
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batteries have an electrolyte solution inside them;  when they get old this solution gets depleted of charge carriers, but i suspect you can recharge them by shaking them all around, thus mixing up the electrolyte and getting a bit more juice out.\n\nalso possible is that when you hold them in your hand when you take them out, the batteries warm up.  this warming means the ions in solution move faster, and therefore have longer diffusion lengths, so you can eke a few more minutes of game time out of them that way.  this effect (in reverse) is also responsible for your car not starting on very cold mornings.
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Sony made batteries for many brands including Dell, HP Apple and themselves among many others.  Here is the scoop however:\n\nSince they may explode only while charging, certain airlines ie Korean Airlines, not the FAA, is restricting the use of all laptops with battery not plugged in, or plugged into the aircraft power without the battery installed to prevent explosion.
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Salt water works better because it's a better conductor of electricity as opposed to just tap water.  In salt water, you have a solution of both Cl- and Na+ floating about creating a means of transferring electricity (electolytes).  So, instead of a saltbridge to provide the transfer of ions, all the ions needed are right there, which will quickly drain the battery.  Think of it as a short circuit - you have a large current because the path of resistance from the cathode to the anode is nothing.  Plus, there's plenty of ions to provide that means of conduction.
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The extra pins can do more than just provide one set voltage.  For example like the previous answer said they can provide battery level info.  Additional pins can also provide power at different voltages for devices such as computers that may require it.  Really the function depends on the battery itself.  Just a note, some Li ion batteries only have + and - terminals, they just aren't usually used for computers and high tech devices
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Yes the + and - charger terminals connect to the + and - battery terminals respectively.  The current reversal relative to discharging causes a reverse flow of ions in the battery electrolyte which restores the charged distribution of reactants.  As the battery charges, these distributions approach the end state, so less current can go into further charging.  This means that although the charger voltage may be initially ramped up with time, starting low to prevent overcurrent when the battery is in its most receptive state and rising as battery voltage increases, the "smart" chargers reduce current as charge approaches full and eventually taper it to a "trickle" rate.  (For lead-acid car batteries, trickle rate is roughly the "100-hour" value, meaning a rate that would charge the battery from completely discharged to fully charged in 100 hours). The trickle charge can be maintained for long periods, keeping the battery fully charged while minimizing water loss due to electrolysis.
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well, i think it is... but just in case, while its charging, move the click wheel around until the screen comes up. then at the upper right hand corner where it tells u how much battery u have left, there should be a picture of a lightning bolt which means its charging. if its a picture of a plug, it means that its done charging.
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You need to specify how much current is going to be drawn from the battery, and also, how long you expect the circuit to operate before the battery needs to be replaced.  If you don't know, describe exactly what the application is, and maybe I can come up with a good estimate.  Note: it's usually a lot better to use a voltage regulator than just a pot.
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It would help if you were more careful in your wording.\n\n"How would one design a snubber circuit for clamping in a flyback converter used as a 250 watt battery charger? The flyback converter switching frequency is 50 KHz and the max duty cycle is 45% on.", is my best guess at what you meant to say.\n\nThere is information on Wikipedia regarding flyback converters:\nhttp://en.wikipedia.org/wiki/Flyback_converter\n\nI am guessing that the snubber would be a zener diode and resistor in series, connected in parallel to the output terminals.\nRather than calculate the value of these components now, I would like to hear more from you regarding the location of the snubber in your circuit...\n\nHope this helps!