volt homemade charger, what are the limitations?
In short, it’s not likely to work hardly at all, but I do not believe anything will “smoke”; as we in the field say. Why I say this: The USB “standard” is to be able to supply 500ma. See reference below. We know that there are computer USB chargers…. Two cell chargers of mine say that they can supply 850 ma and 550 ma. Look at your wall charger for the current rating. The charging current will not be more than about 80% of that number but will most likely be smaller. Seems to agree with the USB spec. There may be a chip in the phone, or whatever, that *needs* a solid 5 volts to work. Your resistor divider will provide that voltage, only with *no* current being drawn. With those resistors, the equivalent source resistance seen by the phone is 44.4 ohms. As current is drawn, the 5 volts will drop. It’s not marked, but based on the size of my Li-ion cell battery it is no more than about 1000 mah. To fully charge it in 10 or 12 hours would take the full 100 ma. If it actually tried to dr
