i want to know how i could wire a rechargeable battery?

i want to know how to wire a rechargable battery that recharges using a usb cable. im thinking of buying something like this http://www.allelectronics.com/make-a-store/item/LBAT-55/3.7V-2650-MAH-LI-ION-BATTERY/1.html if anyone has a better suggestion for a rechargeable battery that is better please tell me.

im trying to put it into this so i wont have the hassle in spending money on batteries http://www.instructables.com/id/How-to-make-a-fast-blinking-LED-bike-light/step7/The-Electronic/

Comments

[iceng]

You are pushing your technology. Step 7 ( you refer ) is a 555 timer. A quick look at the 555 spec supply voltage is max of 18V down to a minimum of 4.5V. The battery you want to use is only 3.7V fully charged. Your blinker would be 0.8V below operating supply ( Sorry it will Never Run on one battery ).

To make this work would be beyond hobby crafting. If you understood the involved electronics you would advise against trying.

[diabloboy]

im aware that its 3.7. thats why i would buy three more so i could get like 11.1 volts

[iceng]

OK, Li-Ion batteries are tricky to charge, if you stay with the USB as a power
source you can not charge the cells in series (only 4.4V is USB guaranteed).

Not that series charging is recommended because Li-Ion cells may not share and one will end-up being under charged or one may get hot. That is why they come with an internal Negative Temperature Coefficient (NTC) thermistor sensors, so you can monitor the battery temperature.

Li_Ion battery charging starts with a current limited source watching voltage up to a fixed voltage point, then a constant voltage watching current down to a minimum value.

As soon as one cell starts heating up or reaches 4.2V +/-50 mV you need to
reduce the charge current. A better method is to charge each cell individually
but a simple series resistor won't do because nobody can watch three or four charging batteries without damaging one in the process.

Here's a pointer to National Li-Ion charger IC's.
http://www.national.com/appinfo/power/files/f7.pdf

Maybe some one, like Apple, makes a smart USB Li-Ion charger that has built in step-up electronics.
I would look to buy an AC line smart Li-Ion charger on ebay.

The following may be useful information;

USB 2.0 can deliver 500 ma at 4.4V - 5.25V
USB 3.0 can deliver 900 ma at 4.4V - 5.25V

A Dedicated USB Charging Port can supply a max of 1800 ma at 5.25V

Sleep-and-charge USB ports can be used
to charge electronic devices even
when the computer is switched off

Battery Li-Polymer rechargeable cell. 3.7V 2650mAh
72 x 40.3 x 8mm overall.
Built-in charge control board with 10K NTC.
Three 38mm leads with female connector
(Molex 51021-0300 or equiv).

Hope this helps answer your question.

[Re-design]

That battery should only be charged using a charger especially designed for li-ion batteries.

Because.

[Re-design]

you could just use 3 - 1.5 volt nicad or nimh. That would let you use the 555 also.

[diabloboy]

would you know of any. and if i could convert it to a usb