3.7 V BATTERY CHARGING

Other Hardware General Electronics
1

Hello friends,

i have a 3.7 lithium polymer mobile type battery,and my supply is 5v.can i give it directly to the battery for charging? please help me... thank you......

2

To charge the cell safely, you need something like this

// Per.

3

Zapro:
To charge the cell safely, you need something like this

// Per.

Sir there is any circuit or components other than a module for charging?

4

ecworks:
Sir there is any circuit or components other than a module for charging?

Yes. The chip itself with appropriate support components.
datasheet

Other chip manufacturers (TI, Maxim, Linear Tech. etc.) have similar chips, even in smaller housings (SOT23-5)

// Per.

5

thank you zapro... sir its danger to give 5 v directly to charge 3.7v LiPo battery?

6

Look to datasheet of your battery. CC-CV method is simple.

7

In essence yes, if the differential voltage is too high you will damage both your 5 volt supply (overloaded current) and the lithium battery due to applying both excessive current and overvoltage. Lithium charging requires both current and voltage control.

8

Yes, overcharging a Lithium cell is bad. Uncontrolled charging is bad. Connecting 5V directly to a 3.7V Lithium cell is bad.

9

Quite a pointless youtube video. It offers no information with respect to battery type, state of charge, voltage applied or current flowing.
However, the recommendations of controlling voltage and current with respect to state of charge still stands.

10

jackrae:
Quite a pointless youtube video. It offers no information with respect to battery type, state of charge, voltage applied or current flowing.
However, the recommendations of controlling voltage and current with respect to state of charge still stands.

It says it's a 5000 mAh LiPo, and it seems to be 2s. They don't say what the charge voltage is, however.

I don't remember exactly what voltage a LiPo burns at, but it is around 5V. I remember this because a couple years ago I had to do a root cause analysis of a 6s LiPo fire in a medical device. In the end part of the problem was a bad lot of cells where one was shorted, resulting in the 25.2V (4.2V*6) charge voltage being split between the remaining 5 cells: 25.2V/5 = 5.04V.

If you have cells you don't care about, hook one up to a DC supply and turn up the voltage. It should turn into a roman candle not far from 5V (or a bomb if you have it packed into a sealed enclosure).