SDK Purchasing Information
From Free Charge Controller
The Free Charge Controller firmware/software development kit (SDK) will be the first publicly available hardware platform for firmware development. The current version is based on the v2.0 hardware. Please see the hardware section for the v2.0 board for details on the hardware. Below are some highlights of the hardware that make it particularly flexible and open to hacking.
High Current Traces
The high current traces connecting the power electronics (page 2 of the schematic) have extra thru-hole mounting points at each node. This allows the easy addition of extra copper wires to decrease resistance, increase current capacity, improve efficiency, and swap power components out for bigger ones - such as the MOSFET, coil, etc.
Surface Mount Parts
Thru-hole parts were used whenever possible. The one exception to this was a 1206 surface mount (SMT) package used for the majority of resistors, capacitors, and LEDs. These large SMT packages are considered by many to be much easier to work with than thru-hole components.
All ICs are in a DIP package and mounted in chip sockets for easy replacement should a mishap occure durring development. The main microcontroller is pin compatible between the ATMega16, ATMega32, and ATMega64. The only IC in an SMT package is U4, the MOSFET gate driver. For this reason, this part will be soldered on the board for you at the time of purchase.
Two expansion headers provide access to all the microcontroller I/O pins. This easily allows for prototyping of additional features and daughter boards - including the control of relays for connecting/disconnecting additional batteries, inverters, etc.
Absolute Maximum Ratings
To program the charge controller, you will need an inexpensive AVRISP mkII compatible programmer. Here are a few sources:
- Mengjin Su @ Fun4DIY sells an inexpensive kit. All you need are basic soldering skills. (Currently out of stock)
- Search for 'AVRISP' on eBay to find many options.
All documents, code, hardware files, and other information on this site is released under the Creative Commons Attribution-Share Alike 3.0 License. You are free to copy, share, distribute, sell, and modify this product so long as you give credit to the author (Chris Troutner and/or Free Charge Controller Project) and distribute any resulting work under a simlar or compatible license.