Don’t spend a penny to make a battery by yourself, Now let me introduce this method
The followed is the required items to make a solar charger and steps.
1. rechargeable?batteries (which can be regular cycle charge)
2. four Neodymium magnets(N42 or N45)
4. solar cells
6. Copper coil
Fold the two ends of? the playing card,then paste the copper coil