Originally Posted by
2manybikes
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.
If your answer were credible, then a best practice for blinky maintenance would be to put fresh batteries in them daily, or at least a couple of times a week. The initial voltage of lithium cells is indeed higher, but it drops rapidly with use, just like other AA or AAA technologies so, here again, constant vigilance with recharging if rechargeable, or frequent replacement, if not, would be the best practice. Erm... no, just no.
Actually the electronics in blinkies are able to function at extremely low battery voltage levels. We've all been behind 'that guy' with the batteries so shot you can barely see his blinky but it is flashing away, albeit at a very low light intensity. There is no need to chuck fresh cells out in the trash for optimum performance. Higher voltage is NOT the issue, poor battery contact, i.e. 'bounce' at the contacts is the only problem. Eliminate the bounce through shims, increasing the spring tension, or the re-adjustment of bendable tabs. Of course if there is corrosion present this should be removed. Paper towel moistened with a weak acid like vinegar or lemon juice does this easier and better than an eraser which may not even be around in most Generation X/Millenial households.