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my solar setup wont work with my joule thief, it just bypasses it. why? Answered

i got a few solar cells wired up in a series to produce around 4 volts, so to get more power from it i connect it to a joule thief i made but the power goes through it and isnt boosted at all. the joule thief works. at 1.5volts it makes around 5 volts. so i cut the power on the cells to 1 volt thinking im overloading the circuit but it is still bypassed.  i even connected a couple of capacitors to the solar cell to trick the joule thief into thinking the solar cells are a battery but still no luck. my question is why doesnt the joule thief boost solar cell power but will boost a dead AA battery?

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steveastrouk (author)2011-11-12

The magnetic core is probably saturating from too much current I'd guess.

A Joule thief is NOT the right circuit to do this with !! You CAN boost volts with other circyuits - there are some really nice chips from a company called Linear Technology that will work well.

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florlayamp (author)steveastrouk2011-11-13

youre right, its probably not a good circuit but i would figure it would work the same with solar cells as it would with batteries. apparently not

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steveastrouk (author)florlayamp2011-11-13

Two reasons: one is to do with the magnetics, and the other is to do with the output resistance of the solar panels which is significantly high, compared to the requirements and load that a Joule thief applies

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frollard (author)2011-11-12

A joule thief doesn't make more power, it just boosts voltage at the expense of amperage (current).

What exactly is happening when you connect the joule thief to the solar panels?

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florlayamp (author)frollard2011-11-13

the voltage passes right through the joule thief circuit like it isnt even there. dont solar cells produce enough current to make it work? these cells can drive a 3 volt motor real easy.

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frollard (author)florlayamp2011-11-13

Yeah; there might be something wrong with the circuit, or applying more than 1 volt to the thief interrupts the oscillations...

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