Inductor based boost converter with LED indicator and charge cutoff at target charge voltage.
Replace 100uF capacitor with capacitor bank of whatever size you need. 100uF takes about 10ms to charge to 149V in this circuit.
Comparator assumes rail voltage. You can change voltage divider feeding the inverting input to change the charge voltage.
Consumes about 20mA in passive mode. LED will light once target charge is reached.
