Backup battery charger circuit
If you need more battery juice while travelling, then you need a backup battery to charge your smartphone. There's a lot of charger but it does not work for a long time. Your charger will die some day. Why? It's true that your charger circuit is damaged.
The battery charger often does a lot of work to increase the voltage from a li-ion cell which has 3.7V to 5V for charging. The IC which is in charge of boosting the voltage will be very hot. If it's working continuously with high temperature, it will die. So, the battery in your backup is still good but the circuit is damaged. Then you need a better charger circuit for your backup battery holder.
We have the backup battery charger circuit which can charge your smartphone at 1.5A (max). It's fast and work reliable. It's a good solution for replacing your current damaged board. I've tested this board for more than 3 months and it still works as normal. For the best performance, you should only use 1 or 2 cell paralleling. This will prevent battery discharging each other.
The circuit has on-board LEDs for charging and discharging status. When your battery discharge and the voltage drop below 2.6V, the circuit will stop charging your phone, you need to plug-in the USB to re-charge the circuit (with battery) for it works again.