I have a PT Switchback 1 bike light that is several years old and the battery is not holding a charge like it used to. PT says the battery is no longer available and the only store on the web I found has it priced at $90. For $100 I could buy a new Niterider Minewt 350 plus so buying the $90 battery does not make much sense.

I measured the voltage on the battery and it was 5 volts. Can anyone recommend a somewhat cheap substute battery I could use for this light?

It seems you have nothing to lose by opening the battery case and seeing what kind of battery is in there. It is possible to but replacement battery packs and install them in PT's battery case. You could also just buy a battery of same voltage, create your own plug and solder it in to the lamp's cord.

For someone used to working with these things, maybe that sounds simple. But for a noob like me, I'm having trouble finding more detailed information for a similar problem to the OP's with the Switchback3.

See thread: https://www.bikeforums.net/showthread...Tec-Switchback