I have an LM317 regulating voltage from a bridge rectifying circuit to charge a 12v motorcycle battery. Voltage measures about 14 but current is only .03 amps. Can I simply change the 240 ohm resistor from the out pin or is this more complicated? Would a Darlington transistor increase current. Not very experienced unfortunately. Would appreciate any advise.

 

Do you have any filtering caps?

 

Yes, 2200 50V for each coil. Output seems to be smooth. I am trying to make a pedal generator to charge a lead acid 4v battery for remote villages without power for lighting. The generator is putting out about .4 amps and 60 volts dc after rectifying. I chose a typical LM317 regulating circuit instead of something specifically for lead acid battery charging. I brought many components from the States but don't have the exact parts for several possible circuits. Would you please advise if there is a substitute for BC547?


file:///Users/keithgum1/Desktop/lead%20acid%20Battery%20charger.webarchive

------BC 547

or, please suggest another circuit.

Last question: Is there such a thing as a current doubler? I tried a Darlington transistor to boost current but was not successful (yet). It appears we need more current and less voltage?

 

That is a transformer. A step down transformer will output a lower voltage than the input, but at a higher current.

 

I am ten hours from the nearest electronics shop in Manila. Is there any commonly used transformer (radio,etc) I might adapt for this purpose? Would the leads of the generator be soldered directly to the transformer?