Off grid solar, DC-DC, AC-DC charging of DIY Lithium Battery

How do you charge your DIY LiFePo4 battery from multiple sources such as your alternator (DC-DC), An AC source you happen to stumble upon, your solar panels, etc. How do you bring all these power sources together to charge your battery with as much of the available power as possible. Preferably on the cheap too.

[@MrGunningpeter]

Hi, I have two 55ah batteries and two 52ah batteries (lifepo4 cells) can I run them in series if I dont fully charge them?