Trying to figure out if I can charge Ipod nano battery with an external charger. I am making a bike flashing light. I figured it does not require that much power and 3.7v should do. I'm not sure if it's possible to charge this ipod nano battery outside the ipod without damaging the battery.
Here are the components: Ipod nano battery
I don't know what connector you've got on the battery you are trying to charge but if you source it you can make charge leads for any of the chargers there that will do 1s (a single LiPo cell).
Your charger might do, but it doesn't have a settable charge current which means it is most suitable for a limited range of cell capacities. The charge current and charge algorithm are unknown so what is it really doing? A hobby charger can be set to appropriate values for charge current and often termination voltage and some degree of overcharge protection by limiting the capacity of the charge. They also show you what is happening (voltage, capacity, etc.) with a display.