Solar *AND* regulated DC power source to charge LiFePO4 battery

[davegravy]

I want to design a power management system for my device that will charge its 12V LiFePO4 battery from either solar (with MPPT) or 15VDC, intelligently selecting whichever is available and gracefully handling situations where both are present.

From my research lots of battery management ICs support MPPT, lots support a 15VDC source, some support 12V LiFePO4, but I haven't found any that do multiple sources. I also haven't seen anything that provides MPPT but doesn't also integrate battery charging control.

I need up to 5A charge current, and it would be nice to have coulomb counting accessible to my MCU but I believe I could use a discrete fuel gauge IC for that.

How should I start thinking about this?