So say I want a fully contained li-ion battery pack, with both charging circuit (5v input) and output 3 - 4.2v) on the same two wires. Trying to work out how one could accomplish this. I have looked for a prebuilt module to perform this task and cannot find anything close. You get either charging modules or battery management, not both. I am not aware of a charging module that sends the battery voltage back out of the same two leads used to power the charger.
This is for an old headlamp with separate lead acid battery pack on the belt. No room in the torch body for a charger. Lead acid is dead and everything is charged through a two-core cable. Our club has a number of these lamps which we would like to convert without touching the charge rack.
I have thought about how to go about this but without very fast switching of input voltages/op-amps it is difficult to work out a simple solution that doesn't involve an op-amp or two, and even then I am not sure it would be safe/effective.
I know it can be done effectively because most phone battery packs have this capability! Just not sure how they achieve the switching?
Any ideas?
This is for an old headlamp with separate lead acid battery pack on the belt. No room in the torch body for a charger. Lead acid is dead and everything is charged through a two-core cable. Our club has a number of these lamps which we would like to convert without touching the charge rack.
I have thought about how to go about this but without very fast switching of input voltages/op-amps it is difficult to work out a simple solution that doesn't involve an op-amp or two, and even then I am not sure it would be safe/effective.
I know it can be done effectively because most phone battery packs have this capability! Just not sure how they achieve the switching?
Any ideas?