Charging issues with Toyota style Denso Alternator

your underdrive pulleys are working against the alternators RPM. Try a smaller pulley on the alternator. What is your estimated alternator shaft speed with your underdrive pulleys (OD of crank pulley / OD of alt pulley X RPM = shaft speed)
PerformanceCurve_0(1).png

Pretty close to your output, this is a Denso graph.