build lithium ion battery


Posted on Feb 5, 2014

The article now describes how to build a charger controller board and how to program the AVR microcontroller. You should have a LiIon battery you can practice on - my practice battery is still alive and well despite considerable abuse. The more you know about the battery the better: Maximum charge voltage and amps (sometimes printed on the case),


build lithium ion battery
Click here to download the full size of the above Circuit.

thermistor (yes/no and resistance - they are not always 10K) and Smart Battery or not. In addition to the charge controller a DC supply capable of providing at least 2 volts more than the max cell voltage (14. 6 volts in my case) at the desired current is required. At the capacities I want you are out of the "Wall wart" category. I found a laptop supply for a Dell rated at 18V @3. 5A. The board is fabricated using easily obtainable components - refer to the parts list in the Atmel App Note. I made some substitutions and marked the schematic up accordingly. The ATMEGA8 is a new release and has 8K Flash, 1K RAM in a 28 pin narrow DIP package and can be clocked up to 16MHz. If you are willing to eliminate the Smart Battery interface and delete some of the debug code the code could be made to fit in an AT90S4433 as per the original Atmel design. The microcontroller software used is GCC version 3. 2. This version is required to accommodate the direct I/O assignments that resulted from the conversion from IAR that was used in Atmels App note. The software is actually a combination of Atmels, converted from IAR, an I2C interface, converted from 68HC11/Imagecraft and my own GCC code. As a result the program does not read as well as I am used to as 3 different styles are evident. The current / voltage control is managed by a PWM output into a P-Channel MOSFET. A large inductor / capacitor combination is used to stabilize the...




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