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charger for 450mAh Li-polymer 3.7V battery

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I have one of these 450mAh Li-polymer 3.7V battery for my RC helicopter, however I lost the charger, and I was thinking if its okey to put my USB's power cable to charge the battery directly?

(USB output 5V and my battery is 3.7V, I saw someone using USB to charge their mobile phone with 3.7v battery before, so I'm not sure if its okey to do the same with my 450mAh Li-polymer 3.7V battery)

I guess the current rating in 450mAh Li-polymer 3.7V battery means how much energy it can hold, so is it means I just need something output 3.7v, but what about the current output for the charger?

Thanks
 

Your Lithium-Polymer battery will catch on fire if you charge it wrongly like you said. The very hot fire is spectacular!

A mobile phone has a charger circuit inside that prevents its lithium battery from catching on fire. You lost your charger circuit.

The charger must measure the cell's voltage and if it is less than 3.0V then it must reduce the charging current until the voltage has risen to over 3.0V.
It must limit the charging current to what is recommended by the manufacturer.
It must regulate the max voltage to 4.20V.
It must measure the charging current then turn off when the current drops to 1/40th the cell's rating.
A Lithium cell must NEVER be trickle charged.

Make a video of your fire and post it here.
 

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