Long, long time ago, when I began to loose my mind and money for RC helis, I came across Lithium-polymer batteries for the first time. My LiPo charger was... let's say "not perfect", so I decided to make something that will suit my needs and satisfy my will of creation - my own LiPo charger with integrated balancer.

I ended up with device that let me charge few LiPo's without blowing them up. I must admit, that the final result was far form being prefect, but it was not that bad either :) Anyway - if someone is interested in something which can be used as a starting point to build something perfect - feel free to use it.

Some info more or less similar to truth:

• balancing cells with current of 100-200 mA
• programmable cutt-off voltage (4.00 - 4.40V)
• programmable charge curent upt to 1.5A (255 steps)
• displaying voltage on each cell individually
• short-circuit protection
• input voltage: 14V min (no step-up converter)
• charging 1-3 cells

User interface based at:

• LCD display
• rotary tact switch
• 4x LED
• buzzer

Circuit is based on ATmega16 working with dedicatem MAXIM LiPo charger circuit, and condiotioning circuit from Texas Instruments.

LiPo - part of balancer circuit: You can see balancer socket and transistors used for cells balancing. BQ2312 is used to (among other features) measure voltage on each battery cells

WARNING!LiPo batteries are dangerous if not charged properly! If you decide to use presented cirucit, you do it at your own risk and responsibility - I do not take nay responsibilty for malfunction of software or hardware.