I've finally managed to set up a more efficient portable charger that uses 8 AA alkaline batteries(actually not so efficient). Schematic:
There are two switches in the schematic:CH1 and CH2.When all the alkaline batteries are fully charged,only CH1 is closed.That will make the regulator dissipate less power.After the batteries are discharged enough(until each one of the batteries reaches ~1,15V) so that togheter they output <7 volts,CH1 is opened and CH2 is closed to continue charging(until the top 2 batteries each reach 1,2V and the rest reach 0,8V(per battery),shutting down the voltage regulator).
I'm not really sure in what package is the regulator,but it has a heatsink attached and I attached another bigger improvised heatsink.It's not heating up too much.
I am sadly using batteries from different brands and I don't think they have the same age(I used some more than the others),but I am constantly keeping an eye out on them.
According to the datasheet,it should output 5V and 1A.
The role of this pack is to charge a dead phone battery for a bit so you can solve an emergency(call someone).
I already tested it on another phone(and it worked great) and on another device which showed some unexpected behaviour(the battery charge level flipping back and forth between fully discharged and a bit charged,but it had some problems before testing the circuit on it).
The original charger of the smartphone I wish to connect it to has an output of 5 V and 1,3 A
Can I freely use the charger with my smartphone without causing damage(Would you use it on your phone?)
EDIT:I understand that the two-switches-activated-simultaneously problem and the differences between the batteries caught your eye,but I would like an answer more focused on the current and voltage supplied to the smartphone,as well as the way the regulator outputs power(is it ok if it's continous?should it be pulsed so it won't cause any damage?)