Smart Battery Charger with Graphical Data Logger

From Open Circuits

Contents 1 Summary 2 Collaborator Anyone? 2.1 Ways of Collaborating 3 OverView 3.1 Screen 3.2 Some Features 4 Hardware 4.1 PIC Hardware 4.2 Analog Charger Hardware 5 Software 5.1 PIC Software 5.2 PC Software 5.2.1 Menu Choices 5.3 Download and Install 5.4 Command Details 5.5 Bugs and Enhancements

[edit] Summary

• Name: Smart Battery Charger with Graphical Data Logger
• Status: still developing, java is close to working.
• Technology: Java -- should run on many platforms, Windows 98 through Vista, Mac, Linux PIC, could be BitWacker or even other microcontroller with serial port.
• Author: russ_hensel ( where you can find an email address to reach me )
• License: not fully determined, but open source and object code.

Purpose:

• A smart battery charger ( one component of which is a PC ) for charging, discharging... NiCad, Nickel Metal, and perhaps other battery types.
• Graphical record of the charge current and voltag.
• A complete log of activity is provided both to the screen and to a log file.

This is one of a series of articles on Microcontroller Serial Communications, rooted at this site here: Microcontroller Serial Communications Articles

[edit] Collaborator Anyone?

Anyone want to help with this project? I have plans for the hardware, but software could support a lot of variants, and you may prefer a different hardware configuration. The Java software I will work on untill it works well enough, but I could use testers, and once it works well enough the code will be open and available for others to enhance.

Some people at the Sparkfun forum seem interested.

[edit] Ways of Collaborating

Anything you want to do is fine, it could include:

• Just building ( and testing ) the charger
• Improving and/or extending the board, a more compact board, adding a PIC and power supply..... are possible ideas.
• Writing alternative PC interfaces for the hardware, some might prefer .Net or....
• Enhancing the Java program ( you need to let me finish what I am doing first )
• Testing the Java -- some can be done using any device with a serial port, I have a simulator that substitutes for some of the hardware.
• You can just lurk, that is participate in a stealth mode.
• Add to the list anything that occurs to you, I will let you know if it works for me.

[edit] OverView

[edit] Screen

File:SBC SS.png

Notes:

• Comming soon

[edit] Some Features

• Charging data graphed and saved to log file.
• May be used to charge, discharge, test, or cycle batteries.
• Charging algorithim on the PC: High current phase may be ended by peaking, time limit, or voltage limit

[edit] Hardware

Hardware will come in 3 parts, the powersupply, the microcontroller and the analog charger section.

[edit] PIC Hardware

BitWacker will be fine, will also have some alternatives. We will need 2 analog inputs, 2 digital outputs, and a third digital or analog output.

[edit] Analog Charger Hardware

Circuit overview. An op amp and darlington transistor will be used as a constant current source. A second op amp will amplify the current signal for input to the PIC. A third op amp will amplify and condition the voltage signal for the PIC. The op amps will be powered by a single 5 volt power supply. Input voltage will be between 12 and 25 volts so that many cell batteries can be charged. To reverse the current for discharge 2, 2 pole relays will be used. The relays could be replaced by a double pole double throw switch ( the user, not the software would have to be used to throw the switch ).

Board design will be in Eagle, single sided for Toner Transfer.

Schmatic ( premiminary )

Board ( premiminary )

[edit] Software

[edit] PIC Software

• Off the shelf BitWacker Software should be fine if used with BitWacker.
• Will have a BoostC implementation for the PIC16F877A and similar
• Roll your own, will need 2 AD inputs, 1 output, and serial link.

[edit] PC Software

Java Based have almost working version.

[edit] Menu Choices

• File -> Exit
  • Closes the comm port and exits the application.

• File -> About the Application
  • About Box for the Application

• More comming as work proceeds.

[edit] Download and Install

See the page BitWacker PIC and Other Microcontroller to Java Communications for the Java Components. For the microcontroller and other hardware email me.

[edit] Command Details

comming.....

[edit] Bugs and Enhancements

See the list at RS232Probe Enhancements and Bugs a list for all the related applications.