So, I can get these batteries very cheap - less than $2 a piece. However, I have no real idea how to use them. (I intend to power a robot with them if I can.) So this begs the question: what kind of batteries are they? Are there commercially available chargers, or is this some kind of specialty unit?
Is it possible to (safely) build your own circuit around these? I feel almost like this is a little off topic, but honestly I don't know where else to ask this question, as I don't know where to start.
Thank you kindly.
Edit: I don't know how much it means, but the were dumped en mass and they have a self-test function on them... some of them are even full (varies quite a bit.)