This version has an OPAMP for the current control, this makes the shunt resistor really small saving a lot of energy.
Below all the precompiled HEX files for various type of battery package, but pay attention, i didn't test
the Lithium family!!! The FLOAT is for car lead-acid battery.
Download charger_v2 FLOAT (HEX inside is precompiled for 13.86V)
Video of the box construction here!