qbone
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Help, Moped Cellphone Charger design
Hey guys. I am trying to built myself a battery charger for my cellphone, powered by my moped.
It is stated on the moped that the output is 6V, which is 6Vac.
So far I have rectified it by making a bridge of 4x 1N5819 so the voltage drop is as low as possible.
Now about the charging. I know that a 3.7V Lithium battery can be charged up to 4.2Volts, so I guess I should make a DC converter which gives 4.2V on the output.
After the rectifier I have about 5.35Vdc.
How do you suggest I go about designing this circuit?
I don't have time to order all sorts of fancy party like MAX1555, which I know would be the best way, but I do have a series of 78xx, LM317, LT1074 and MC34063 ICs available.
And all sorts of inductors, capacitors and resistor.
Could you help me out?
The cellphone is a Nokia 6100, and the Battery is a BL-4C rated 3.7V 820mAh.
Could I do it so that I make a voltage regulated circuit from one of the above ICs and limit the voltage to 4.2V and limit the current to something like 10c? (82mAh) - or how much do you think is safe?
One guy told me that if I charge it with something like that it wouldn't blow up the battery, and would just stop charging when the battery level reaches the output from my voltage regulator.
If someone has a diagram this would be much appreciated.
So far my diagram is very small to say the least, but I can post it if you wish. So far its just the rectifier, a capacitor and a transcient diode.
Hey guys. I am trying to built myself a battery charger for my cellphone, powered by my moped.
It is stated on the moped that the output is 6V, which is 6Vac.
So far I have rectified it by making a bridge of 4x 1N5819 so the voltage drop is as low as possible.
Now about the charging. I know that a 3.7V Lithium battery can be charged up to 4.2Volts, so I guess I should make a DC converter which gives 4.2V on the output.
After the rectifier I have about 5.35Vdc.
How do you suggest I go about designing this circuit?
I don't have time to order all sorts of fancy party like MAX1555, which I know would be the best way, but I do have a series of 78xx, LM317, LT1074 and MC34063 ICs available.
And all sorts of inductors, capacitors and resistor.
Could you help me out?
The cellphone is a Nokia 6100, and the Battery is a BL-4C rated 3.7V 820mAh.
Could I do it so that I make a voltage regulated circuit from one of the above ICs and limit the voltage to 4.2V and limit the current to something like 10c? (82mAh) - or how much do you think is safe?
One guy told me that if I charge it with something like that it wouldn't blow up the battery, and would just stop charging when the battery level reaches the output from my voltage regulator.
If someone has a diagram this would be much appreciated.
So far my diagram is very small to say the least, but I can post it if you wish. So far its just the rectifier, a capacitor and a transcient diode.
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