From what I've seen, LiFePO4 batteries seem like one of the top battery choices for robotics applications. However, I've seen people mentioning that you can't use a charger for a different battery to charge these, but I haven't seen why. If I were to build my own setup to charge LiFePO4 batteries what would it specifically need to do? What kind of voltages or current rates does it need to supply to charge these?
More specifically, I was think about setting up a solar charger for these batteries. Is there any immediate reason why this is a bad solution? Such as, the battery needs to charge with a current above some amount for it to work properly?
If you're ambitious enough to provide an example along with your explanation, I'm specifically thinking of having 4 of these batteries with 2 pairs of 2 in series in parallel.