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Battery charger circuit? Answered

Hi,
Can someone help with a simple battery charging circuit? It is to be attached to bicycle dynamo to charge the 4 V battery. Now the power generated by the dynamo would be fluctuating depending upon the RPM. So need to build a charger that would ensure constant supply to the battery. Preferably simple and economical circuit as this would be used on some charitable work. 

Discussions

Will check for battery type, am not from tech background so didn't foresee it, but thank you all for the help !

Lead Acid? Lithium Ion? Nickel Cadmium? etc? Each chemistry requires a different charging paradigm and most are far less forgiving than say, Lead Acid.

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iceng

3 years ago

Not being familiar with the LM715 Op-Amp,

I would generate near 4 volts like below and

"then feed that into the charge controller that is designed for that battery." as

Mpilchfamily said.

BIKE12Reg4.bmp

Use an LM715 to take the voltage from teh dynamo and regulate to 4V. See the data sheet for the LM715 for a basic schematic and instructions for setting the correct output voltage. Then feed that into the charge controller that is designed for that battery.