FWIW with regulators it's best to use a pair 3.7V batteries if you want to maintain 5V for any length of time (especially regs like that which drop below the target voltage).checked with the voltmeter and the power is always on. good thing is that it lets through below 5V like when i have a single 18650 in. with 3V batts in i get 4.99V... now how do i fix this switch?