# How would I make a 4700u cap charge faster if the solar cell in parallel has a max output of 4.5V and a very low power??

I'm still working with my fled solar engine. I have a solar panel that can output a maximum of 4.5Vdc.. The solar panel is connected in parallel with the 4700u cap.. The motor only requires al least 3Vdc to function. I used 2 solar cells (1.5Vdc max and 3Vdc max) connected in series as my solar panel/power supply.. I thought that this might work since I only needed a 3Vdc solar panel to charge my capacitor, but it does'nt. I tested my solar panel and connected it in parallel with the capacitor and i measured the stored voltage using a multimeter. The capacitor only stored 0.7V (and this was when my solar panel were at its max!!)..
It seems that the solar panel has a very little power output.. What should I do?? How could I make the 4700u cap charge faster??

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steveastrouk8 years ago
Is the motor always connected to the capacitor ?

Steve
beannie (author)  steveastrouk8 years ago
yup.. a terminal of the motor is connected to the positive of the cap and the other terminal is connected after a certain resistor value. I already posted this sort of problem in this instructable: FLED Solar Engine by TEXTCLA55.. see the schematic there..
8 years ago
What you need to do is store the juice for a period determined by the voltage on the cap. If you take a look at the little robots here.<a href="http://www.pagermotors.com/Products.php?f_category=Robot">www.pagermotors.com/Products.php</a> you'll see circuits in them which will do what you want. <br />
framistan8 years ago
Your LED must have a SERIES resistor going to it.  I suspect you connected your LED directly to the capacitor.  Since the LED is a diode, it will ALWAYS have point seven volts across it (even WITH the series resistor).  The resistor limits the amperage to the led to about ten milliamperes.  measure your voltage across the LED plus RESISTOR combination.  if you just measure across the led, you will always get about point seven volts.  Without the resistor, you will burn out the led. Also with wrong polarity going to the led you will burn it out.  it is difficult to answer your question because we dont really know the diagram of what you built, and we dont know your skill level where you measured...etc..... hope my guessing what you did helps you a little...
beannie (author)  framistan8 years ago
but its not an ordinary LED. its a flashing LED (FLED)..
cyberpageman8 years ago
Sorry, I see you already said your solar panels together put out 4.5 v.  There is not much you can do to speed up charging if the panels don't put out much current.  There are way of increasing the voltage (see "Joule Thief") but this won't help because the current is still low.  The best thing is to get more solar panels.
cyberpageman8 years ago
<span class="Apple-style-span" style="font-family: 'Times New Roman'; font-size: medium; "><div style="background-color: rgb(255, 255, 255); padding-top: 5px; padding-right: 5px; padding-bottom: 5px; padding-left: 5px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 12px; "> There is some description of "how-to" at <span style="color: rgb(255, 82, 0); text-decoration: none; cursor: pointer;">http://www.edn.com/article/CA56664.html<br /><span class="Apple-style-span" style="color: rgb(0, 0, 0);">I'd think if you connected a 1.5 v and 3.0 v solar panel in series, you'd get 4.5 v. Did this happen?<br /></span><br /><span class="Apple-style-span" style="color: rgb(0, 0, 0);">I'd think you'd need a diode between the cap and solar panel. Check out "diodes" on the Internet for an explanation. They allow current to pass only one direction, so that when the voltage from the solar panel drops, the capacitor won't run a current through the panel.<br /></span><br /><span class="Apple-style-span" style="color: rgb(0, 0, 0);">4500 F is a big capacitor. Fool around using a smaller one, maybe 10-20 uF--try to light a LED with it (don't forget to add resistor to the LED--maybe 100 Ohms). If it lights, see how long it stays lit. Calculate the current drawn. Measure the current if your meter has a mA scale. If you can measure the current produced by the solar panel--it may not be enough to charge the capacitor. Also, motors draw a lot of current. You can measure it using a 1.5 or 3 v battery and your meter to get a feeling for what is going on. <br /><br />There is an article on Ohm's law at </span></span><span style="color: rgb(255, 82, 0); text-decoration: none; cursor: pointer;">https://www.instructables.com/id/About-OHM-and-his-LAW/</span></div></span>