Most manufacturers publish detailed charging info in their datasheets. If you are interested in more detailed info a web search will turn up several of these, along with some projects for building your own chargers using the various battery charging chips available from Dallas, Maxim and others.
I’ve considered setting up a custom charging station using one of those chargers so I can top-up these tiny RC batteries after I’m done running the car for the day. I’m thinking that I could use the quick-charger that comes with the car while playing and let it charge up normally after I’m done.