I want to make a battery pack with mains charger to power my tablet that has a wonky battery. It lasts all day if I do not use WiFi, but with WiFi it dies within the hour.
I have 4 Nokia BL-5C 3.7 V 1000 mAh and 2 Nokia BL-6C 5v 1000 mAh batteries (but no way of charging them.
Is there a way of using either of the batteries I have (in series?) and make a circuit to charge them while still connected to the tablet via its DC in?
I was told at Uni by a techie, that I need to make a charging unit, but has a "step down" out put to the DC in of the tablet. In theory it could charge and supply power at the same time, but with a switching circuit would act as a plain battery?