Originally Posted by
ItsJustMe
It won't be the switch button breaking contact, it's normally open on almost all blinkies and closes when you push it. I think it's almost certain to be the battery contact. Probably not corroded either, I think the mass of the batteries is just forcing them down when you hit a bump and causing the one with the negative downward to momentarily break contact with the top contact.
Exactly.
The contact interruption is so minor that the higher voltage from new batteries will almost certainly fix it.
Unless it is very cold, that makes it a little worse. I have fixed many, lights that got "bumped off" this way.
After spending most of my life doing this kind of thing for work, I've learned that it is not unusual. It happens in all kinds of electrical things. Plus it's easy to try. I shimmed my battery support piece of the cover that keeps the batteries in place in my Radbots with a small piece of inner tube. That can help too. It's not the switch.
If you want the light to work better, the higher voltage from lithium batteries will help too.