RC helicopter needs a new battery
My old RC helicopter is no longer charging and I think the battery is exhausted and needs to be replaced. It contains a 3.7V 100mah battery called 601720.
I have been looking for it online, but cannot find anywhere I can buy a battery cheap. Alibaba has minimum order of 1000 pcs. On other online stores they have other models of the 3.7V 100mah battery. Like 651620 or 751517. What is the difference between these models? Do I need the 601720 battery that I cannot get hold of?