A complete 12v 6v battery charging system built on a PIC16F628A microcontroller, a very powerful 16.6 amps 2xlcd display with charge voltage, current and temperature can be observed (volt ampere with lcd display can give an idea for a simple measurement circuit for heat) source .asm .hex files prepared with software assembly language exists.
The cyclic voltage is usually different for each type of lead acid battery. For example, standard lead acid batteries should be charged up to 14.2V and charged up to 13.4V, Gel-Cell (Sealed Lead Acid) batteries should be charged up to 14.1V and 13.3V respectively.
These voltages are for a battery temperature of 20°C. At high temperatures, voltages need to be reduced and the amount of compensation also depends on the battery chemistry. Typically, lead-acid batteries require -20mV/°C temperature compensation while Gel-Cell batteries require -25mV/°C compensation.
Obviously, a low-cost charger has no way of adjusting the required cyclic voltage and cannot provide voltage regulation or temperature compensation for these voltages.
The Battery Charger is built on three boards. The power control components are mounted on a fan assisted heatsink that is cooled using an 80mm 12V fan. The transformer is a 300VA toroid.
The front panel contains the power switch, control switches and LCD module. On the back of the case are the charging cable, temperature sensor input socket, fuses and cooling fan. It also has a finger guard to cover the fan blades.
Charging circuit Main Features
Suitable for 12V lead acid batteries
LCD shows charging stage and settings
Temperature, voltage and current measurement
3-stage charging
Optional sync phase
Battery temperature control
16.6A charging capacity
Initial trickle charge when battery voltage is low
4 preset battery chemistry settings
2 adjustable special battery settings (adjustable for 6V batteries)
Voltage drop correction on battery cables
Wide battery capacity range (4-250Ah) in 18 steps
PIC16F628A Fast Charge Circuit
source http://www.siliconchip.com.au/cms/A_103191/article.html http://www.siliconchip.com.au/cms/A_103239/article.html
PIC16F628A Fast Charge project source code schematic pcb files alternative links:
Password: 320volt.com
Published: 2009/02/04 Tags: battery charger circuit, pic assembly example, pic16f628 projects, power electronic projects
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