ATTENTION: THIS PROJECT IS NOT FINISHED YET! IT'S ONLY PROVIDED AS "DRAFT"!

PIC R/C Accucharger

This is the second generation charger for R/C accus. It has evolved from 1st generation charger and it has some benefits over the older design:

It has 4 accu stations, eg. you can leave 4 accus to charge overnight. It first charges 1st accu, then 2nd and so on. If accu is ready, green led will be lit on that station.New feature
It has 4 row LCD-display where user can watch as charge-process goes on. It shows time, temperature, accu-voltage and cumulated mAh charged so far. It also shows what accustation is being chargerd and what stations are ready. 4 rows = new feature
It can charge NiCd, NiMh and LiIon accus.
It has 10 memories for different type of accus.
"Programming" can be done ordinary PC via serial port (eg. normal "Teraterm" or similar terminal-program will do fine for setting up the charger)
It can stop charge based on voltage or overtime. In 1st station there is also overtemperature warning.

The heart of system is PIC16F876-microprocessor. There is separate PIC16F84 for controlling the LCD and leds. Code has been made in CCS-C. I'm releasing this so soon because general Open Source method is to "Release soon, release often" and I'm hoping that it will be useful for someone already.

Items needed

Basic knowledge of PIC-microprocessors (specifically, how to "burn" or "prom" the .hex-file in to them.)
Basic soldering abilities
Basic knowledge of accus and how they are charged. This project relies on operator to know what he/she is doing. The charger will not stop you from blowing your accus by overcharging them or charging them with wrong setups... So be careful and gather basic knowledge of accus before you try this charger. ("The power comes with great responsibility" they say... Same rule applies here...
Normal PC for controlling the charger. Any operating system (Windows, Mac, Linux etc.) will do fine, as long as it has some sort of terminal software (in Windows, Teraterm or Terminal will do fine, and in Linux minicom is fine. With Mac, well, it should be minicom also...). In the future, there will be GPL'ed software for at least Windows and Linux for controlling the charger. It could easily "backup" memory locations and calibration values, draw charts of charging current, voltage, temperature etc. etc.
Ability to make some sort of PCB for charger. It could be normal patch-board, PCB made by "normal" etching methods or it could be milled with prototype-miller (as we do). The main thing is that you have the parts and they are connected together in right way :)
Some R/C accus to test charging with
Power supply capable of at least 2V higher output than your biggest accu. So if you have accu that will be 10V full, you'll need 12V power-supply. It should also be able to deliver the current needed for charging, typically somewhere in the range of 100mA - 5A. You'll set the charging current in each memory-location separately.

We could provide you with preprogrammed PIC's if you can't prom them for yourself. But please, first try to find someone in your local area who has the knowledge of doing "PIC-promming".

Current status of the V2-charger:

22 Feb 2004: Basic schematics are ready, mechanics under construction
29 Feb 2004: Mechanics and power supply (0-24V/4A) almost finished

Files:

V2 Eagle files

Normal disclaimer

Well, as normal to assume, we will not take any responsibility if you decide to try this and burn your house down with LiIon charging process. All source-code is released under GPL licence. It basically means that you can modify, transform or even sell the product based on this sourcecode. But you must provide the sourcecode you modify freely available to anyone who want's it.