Emergency charging car battery with 4 li-ion cells, possible?
Hello, I'm trying to make a DIY emergency charger for my car battery. Is it possible to use 4 li-ion cells in series? That will be 4x4.2volts at full charge of the cells. I think i should limit the voltage and also the current with some sort of circuitry. Considering that I will use this when the car battery is almost fully discharged, there will be a huge power draw. Any suggestions?