Originally posted by Aaron
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Unfortunately, charging up an empty capacitor needs energy that is taken out from a battery, a solar cell etc. And slowly you source dipole is killed in case of a battery if you do not take care of recharging it but then it needs outside energy. (Of course when using a solar cell you do not have to care about recharging.)
There is one more problem: when you charge up a cap from a source dipole the amount of energy you take out is mainly governed by the capacitor value. If you use a very 'big' capacitor like say a supercap so that you do have a decent energy source to supply a load, then the source dipole also "suffers" (loses energy) while charges up the supercap (or a very big value cap).
I understand you can charge up a cap many times from a battery but all that happens is you slow down the "killing process" because you do the discharging intermittently.
I also understand that you can have a higher energy output from a cap than what is stored in it if you discharge it in a very short time. Tesla nicely described it. (Say you store 10 Joule in a cap and you discharge it in half a second you can have 20 Joule for that half second.)
BUT unless you can gain some extra energy from the very quick discharge, all you do is consuming the cap's energy by your load in a faster way. So you have to charge it up more frequently from the source dipol, this involves consuming more and more energy from the source dipole: you have to recharge it if it is a battery. If it is a solar cell you load it more frequently by charging up the cap but if you think it over you cannot utilize as much energy from the cell (if you choose the charge / disharge process) as in a continuos operation without using the cap (switching losses).
I would yet like to see a practical setup where a source dipole can trigger a process that involves energy gain, preferably without using rechargable batteries anywhere in the process, except for a startup.
rgds, Gyula
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