Instructables

What is wrong with my anyvolt3?

I am trying to find the best way to use a bike dynamo to power gadgets as I cycle around town.  I use a bridge rectifier to convert to DC, then a capacitor for smoothing, then an lm317 adjustable power regulator to set the output to 12 volts.  This way I can power any car charger accessory with my bike like a phone.  I can draw .5 amps from it.  From what I understand, adjustable regulators are inefficient because any voltage above the target voltage is burned off as heat.  Adjustable switching regulators are better because they convert nearly all  incoming power into usable electricity.  

My problem is, I can only draw .1 amps from the dynamo with the anyvolt3.  Everything else is the same.  How could a $2.50 lm317 work 5 times better than the $55 anyvolt3?  What am I doing wrong?

Take a look at the input voltage to the anyvolt with an oscilloscope. I suspect its input current demand is so spiky, its upsetting itself. The scope will nail it.

More capacitance, and using low ESR caps may help.

Steve
frollard3 years ago
how much current (total wattage) can the dynamo output? Where is the anyvolt in the circuit? after the rectified smoothed dc I hope...in which case it should output whatever the specification is if it's supplied with enough juice.