My tiny 9x9 mm heat sinks arrived, so time for a test!

They really don't look like much, but they do work! Temperature of the PCB with and without the heat sink rises to ~64 °C, but obviously the thermal current limitation is limiting at a higher level when the heat sink is present, allowing the voltage to crawl out of the "valley of death". :)

What would be ideal is to log the current in each case and compare the charge current with and without heat sink. I have to figure out a way to automate this though, since I'm working on other stuff while these tests run. What I am doing is having the Pi record a log of the voltage, so I'll be able to compare this data at least. Stay tuned!