Strange problem with Panasonic NCR18650's across 5 different flashlights.

Yes. I push the button and it’s high, the light will stay lit. Push the button again, a very rapid blink. Repeat this on this flashlight, until it has cycled back to the high function, when it will once again stay lit.

On a couple of the lights, I also get a low beam which stays on.

And it doesn’t appear to have anything to do with whether it’s a 5-mode light or a 3-mode light.

Is it just me that LIKES the idea of a cell that eliminates blinky modes? J)

The protection circuit is at the top, right? (+end)

Do I literally remove the entire top piece?

The bottom. See: The Anatomy of a Protected Battery

Ok, and what about the flat wire? Can that come off too?

I hate that darned mode, too. But it’s even more irritating when it only blinks once, because it’s so bright.

It’s kinda up to you how much you remove. You can strip the whole thing back so it’s a bare flat top cell if you like (leaving the original Panasonic wrapping on of course)

I still don’t understand how you end up with a strobe mode that pulls more current than a high mode, especially when the driver is regulated. In other words, why isn’t high tripping the protection too?

Ladies and gentlemen, we have a winner!

I just took the end off of one, and that battery works perfectly in the 4 different style of flashlights I have here.

You’re confusing me. Isn’t this thread about you being unable to access blinky modes (aka strobe etc)?

I meant a single blink that is very rapid.
The very first blink of the strobe was apparently tripping the protection circuit.

I like the idea of just having the flat top at both ends, but that won’t make the battery too short will it?

The only real concern is whether any of your flashlights are without a spring on the bottom of the driver board. If they don’t have one, flat tops are unsuitable. You also wont be able to reliably use flat tops in multi-cell lights, if you ever get any.

Ok, and in the case of multi-cell lights i’ll be ok with the newer black series of Panasonic that Pulsar13 linked, right?

When you switch the light on/off, there's always an electrical spike. This can be very high current for a few microseconds, but relatively harmless since it's very short. These spikes are way higher current than running on high etc.

However in this case, the protection circuit in OP's battery is sort of overprotective, it saw this current and immediately shuts off, thinking it was a dead short.

Think of it as some kind of allergic reaction.

And it’s funny in an odd sort of way, that this batch of batteries was probably stronger than they anticipated for, when they put the protection circuits in there.