No Strip On Top Of Protected 18650

I just realized that I have three protected 18650s without the strip extending across the top, and with no vent holes or whatever they are. These are generic blue cells, like AW's, and could be AW's but I don't know since I get them from different places.

So, if they were actually unprotected would they be a different length (they're the same as the normal ones) than the protected ones? They appear to have the strip down the side, but for all I know this could be wrapper overlap.

If they are supposed to be protected, would the missing strip on top negate the protection?

If it's still protected, how important are the holes?

In other words, should I ditch them, or not worry and just use them.

Thanks.

Re: No Strip On Top Of Protected 186500

I don't know the answer to your question, but what your Sig quote from? I like it!

Re: No Strip On Top Of Protected 186500

It's from the song "It Takes Time" by Patti Smith and Fred Smith. I first heard it on the soundtrack of the film "Until The End Of The World," one of my all time favorite movies, and a spectacular soundtrack.

Re: No Strip On Top Of Protected 186500

Bob,

Can you post some pictures ?

AW

Re: No Strip On Top Of Protected 186500

There are many protected cells that "don't" have strip across the positive end as it's done internally somehow and you may or maynot see a wire running under the wrapper.

The only way to "really" tell is under load, either reading current and/or voltage.

Re: No Strip On Top Of Protected 186500

AW,

I'll try I'm not sure what you want to see, but here's a couple. The known good is on the left in both. They both have the indentation on the negative end, which I've always assumed was the pcb or whatever, but I thought they needed the strip across the top.

wptski says above that this isn't so however.

wptski,

I don't have any way of loading them except to use them, so that's what I'm doing The plan is to keep a close eye on them, but they're on a boost driver - BB - and I'm thinking that's a bad idea, so will probably put one on a DB instead.

Thanks for the input.

Re: No Strip On Top Of Protected 186500

BobG:

The one on the right looks like there is a flat strip under the wrapper, correct? If so, it's connected on the inside as I mentioned above.

The right one looks to be protected. It does have four vent holes on the top.


AW

Okay, I see what you're saying, I've never been sure how these things actually worked. Thanks AW and everyone.

Most of the good cells dont have that strip.

AW said:

The right one looks to be protected. It does have four vent holes on the top.


AW

Click to expand...

The 4 holes have nothing to do with the cell having a protection circuit, they're vent holes to discharge gas buildup instead of having the cell explode.

The side strip is present in all protected cells ( connecting the +ve and -ve for the PCB ), some are cold welded on the side on the top button out of sight. The vent holes and the crimp indicates there is a PTC inside ( the crimp to hold the two discs in place ).