I then decided that the TI evaluation board was not a very good fit to the project. Instead, I wanted something that could easily connect to a battery, a charger and an iPod. And it had to be able to drive 4 ohm speakers, since that's what all car speakers are. So in May of 2008, I designed my own PC board using a TPA3100D2 chip, which is similar to the other one but could handle the 4 ohm speakers. I brought it to Burning Man in the wood box for use as a camp stereo, and it worked rather well.
Another problem manifested during this prototype period. The TI chip was prone to blowing out one channel, presumably due to static discharge on the iPod connector. A chat with a TI app engineer confirmed this.
The CDAMP board had a battery charging circuit, but it wasn't designed properly to charge the 14.8V lithium-ion pack from an 18V solar panel. I ended up bypassing the charging circuit at Burning Man.