Off Grid Home Forums Technical Discussion Using capacitors instead of a battery

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    that’s a nice piece of equipment, but a high cost for only 130 watts. there are cheaper alternatives, but the concept is the same. it may be possible to step down in octaves of volts. converting from 70-90 volts down to 12 would pull much less current from the capacitor bank than when the bank gets down to a lower range like 15-30. my thinking is, converting from such a wide range would have inherent inefficiencies.

    EDIT: actually, thinking about it, how complex would the charge controller be to efficiently charge the capacitor bank from solar panels? you wouldn’t want 90 volts going into a dead bank, as you’d have much current loss without converting it down.


    That particular converter is designed to be used in a diesel locomotive, where the voltage is very dirty, to say the least, and fluctuates up/down constantly. I imagine that there would be alternatives much cheaper, being the source would be much cleaner..

    Through experience, it’s rare (in my situation) to use 10 amps at any given time, on the norm. All of the outlets I use are only good for 4-5 amps maximum. Even when everything is in use in a normal day, my trimetric isn’t displaying any more than 6-7 amps, even during a shower when the pump is on. Might require multiple converters for amperage limited circuits but never a need to buy batteries again..

    Ohms law.. higher voltage, less current. Capacitors hold voltage which is consumed by resistance. (Load) Higher voltage reserve means less load from the converter to feed the useable (lower) voltage loads throughout..

    One wouldn’t need a controller. Just a blocking diode to avoid the stored voltage from going back out to the panels at night from the capacitors..

    The open circuit voltage of the panels comes into play. Most 12 volt panels have an open circuit voltage of ~21-22 volts. (no load) Using 22 volts as an example, 5 in series would be 110 volts D.C. The capacitor bank would need to handle at least 110 volts. When the capacitors were fully charged, it would show as an open circuit to the panels. The amount of panels (current/wattage) would define how fast the capacitors would charge as long as they were kept (in this case) in groups of 5 connected in series and combined in parallel. The individual panels should be designed to withstand the current that they make. The wiring to the capacitors should be designed to carry the current produced by the panels per distance and lowest possible voltage.. (lower limit of the converter)

    Also, in this case, a gasoline back up generator could be adjusted to charge the capacitor bank directly @ 110 v.d.c. Adjust the R.P.M.’s down to 110 v.a.c. and put a full wave rectifier Inline.. Simple! The c.p s. (cycles per second) wouldn’t matter..


    Idle Current: (including power “on” indicator light) approx. 50 mA

    Efficiency: 85% – typical.

    Batteries are only 80% efficient..

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