Lithium Polymer Battery Charging Circuit

The battery charger circuit is designed for 7 4v lithium battery pack two 18650 in series which i commonly use in most robotics project but the circuit can be easily modified to fit in lower or slightly higher battery packs like to build 3 7 lithium.

Lithium polymer battery charging circuit.

The 10 k preset positioned at pin3 of the opamp is used for setting the over charge level for a 3 7 v li polymer battery this may be set such that the output of the opamp goes high as soon as the battery is charged to 4 2 v for a single cell. The advised charge rate of an energy cell is between 0 5c and 1c. In a li ion battery lithium ions move from one intercalation compound to another while electrons flow around the circuit to power the load. Do not draw more current than the battery can provide say about 1 2c.

There are five main things to watch for when charging and using batteries. You will be able to prolong the usage of these battery type. The second simple design explains a straightforward yet precise automatic li ion battery charger circuit using the ubiquitous ic 555. In this project we will build a two stage battery charger cc and cv that could be used as to charge lithium ion or lithium polymer batters.

Set up the battery balance circuit. I use 300ma for the 18650 li ion battery. Digi key today s cells use lithium based intercalation compounds such as lithium cobalt oxide licoo 2 for the positive electrode as it is much more stable than highly. Set the 1k trimmer slowly until it starts emitting light or tl431 ref with 2 5v at the foot.

If you are using a trickle charge most chargers uses topping when the level of current drops. 4 4 out of 5 stars 22. Do not charge them above their maximum safe voltage say 4 2v usually taken care of by any on cell protection circuit. Free shipping on your first order shipped by amazon.

First set the voltage of your set power source to 4 25v. Knowing these simple tips for properly charging your lithium ion batteries will take a long way. Fully charging a battery can take from 2 to 4 hours depending of the charge rate which i recommend to keep between 0 5 and 0 7c. Get it as soon as thu sep 17.

A li ion battery as we all know needs to be charged under controlled conditions if it s charged with ordinary means could lead to damage or even explosion of the battery. However most power cells can take a higher charge c rate with little stress. The current drawn from the power supply is a value between 100ma and 400ma according to the power of the battery. Charging li ion battery can be critical.

The complete charge time is about 2 3 hours. Do not discharge them below their minimum safe voltage say 3 0v usually taken care of by any on cell protection circuit. When the current flowing into the battery is less than 3 10 of the nominal capacity the battery is 100 charged and the circuit above is what will tell us when this happens.