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[on:]

hi all,

  i am new to lipo battery and am using AA batteries for my 1st robot. May i check what is the type of lipo battery i should buy and the charger as well? thanks

regards

[Reply #1 on:]

You need a couple of things:

Lipo battery / with a battery protection circuit
Balancing charger
Voltage regulator

Most hobby lipos run from 7.4 to 11.2 volts there are higher and some lower but they are hard to find.

The charger needs to properly balance the cells, this can be done by the charger or by an external device.

The voltage regulator to reduce the voltage to what you need.

That is the really simple explanation, for more information on lipo and chargers most R/C car or Helicopter sites have much more detailed information.

[Reply #2 on:]

thanks for your prompt and helpful response. but am curious, isn't the voltage regulator is in built with the charger? how to determine whether i need the 7+v type or 11+v type? i will be powering up my 1) motor driver 2) arduino board 3) sensors (IR + ultrasonic + IR(RYB)) 4) communication (bluetooth). do i need to take note of the amperes? thanks

[Reply #3 on:]

You likely want a "2S" (voltage is 2 * 3.7V = 7.4V) type rather than a "3S" (3 * 3.7V = 11.1V). You want the least amount of difference between the battery voltage and what voltage you'll be regulating your power to (which I assume is 5V).

The "C" rating of the battery tells you the amount of current the battery can discharge. For example, a "10C battery with 2200mah capacity" can discharge at a rate up to 10 * 2200 = 22,000ma (22 amps). HIGHLY unlikely you'll be using anywhere near that much power unless you're using some pretty big motors. "10C" is a pretty low rating for LiPo batteries so it's unlikely it'll be a concern for you.

Back to the capacity, the "2200mah" rating means it can provide 2200ma for one hour, or 1100ma for two hours, etc. Coincidentally, an alkaline AA battery is also around 2200mah so if you're running on AA batteries now then you have an idea how much more capacity you need or want.

[Reply #4 on:]

If you know what lipo battery you like to have, it's a good idea to look around on ebay.
You can buy them and also the lipo loaders for a good price...

About the voltage regulator, i guess you need that one for your arduino, so it isn't fried.

To load a lipo you need a charger which is capable to load the amount of cells of your lipo, a one, two or three cell etc.
Also there are chargers available that can load all these kind of lipo's

http://www.ebay.com/sch/i.html?_nkw=lipo&_dlg=1&_ds=1&LH_PrefLoc=2&LH_BIN=1&LH_FS=1