Foursevens MMR-X plastic disc not necessary?

I recently purchased a Foursevens MMR-X from someone, after I saw that Foursevens has gone out of business. I searched around and found one that was supposed to be new and unused. When I received it, I found that it does not have the plastic disc in the tailcap, which is used to block the outer spring contact for the battery in the head end of the flashlight.

My understanding is that this is necessary if one wants to use a regular 18650 battery in this flashlight, otherwise it will short by have both a negative and positive contact touch the positive end of the battery. (The MMR-X comes with a special version of the 18650 designed to use both of these contacts, so that the battery can charge in the flashlight. This is explained in this review: http://www.candlepowerforums.com/vb...L2-1x18650)-Rechargeable-review-RUNTIMES-BEAM.)

The person I got the flashlight from said that the disc in unnecessary and stopped shipping with the MMR-X after a couple years. Is this correct? Can I use a regular 18650 battery in the MMR-X without masking the extra outer spring contact in the head end of the flashlight?

Thanks for any feedback on this.

From a bit of reading this morning, I would say that you are correct. The disc should be used with non proprietory cells.
Are you absolutely sure it's not there?
Here's a picture from flashlightguide.com, if i hadn't known it i would have assumed it was part of the switch..


Jim says
"A standard 18650 battery may also be used to power the MMR-X. Before installation, the plastic insulating disc must be unscrewed from the tailcap using a pair of needle-nose or snap-ring pliers inserted into two holes.The insulating disc is then placed into the battery tube so that it prevents the outer spring from contacting the positive terminal of the standard 18650 battery."

From that picture of the tailcap, it shouldn't be too difficult to make your own using the tailcap as a template. Especially as you can remove the switch, it should be easy enough using the plastic from a milk bottle or similar.

Good luck.
P

Thanks for the reply. Yes, I saw pictures like that and a similar explanation of the purpose of the disc in the review here in the forums that I link to in the OP.

The disc is definitely not there in the flashlight I got. What's strange is the the person selling it claims that two years after release (both the reviews were written in 2014 when the flashight was released) the disc was no longer necessary. And he even said, "we" stopped including it, making it sound like this is a former Foursevens employee sellling off remaining stock.

But I have not gotten a response from this person as to how it is that the disc was no longer necessary. So I'm wondering if anyone else knows anything about this.

Thank you also for the suggestions about how to fabricate a replacement disc for this purpose. I also wondered if simply taping around the outer edges of the positive terminal of a standard 18650 with electricians tape would be good enough.

And how worried should I be about experimenting and possibly shorting a lithium ion battery? Can it explode?

gg555 said:

And how worried should I be about experimenting and possibly shorting a lithium ion battery? Can it explode?

Click to expand...

Don't do that - if you short it you will at least get burnt. Li Ion can deliver a lot of current.
P

I put the previous post up when i saw yours as I was worried you'd do something dangerous if not - I've now woken up a bit.

Taping the head of a cell will not stop it shifting and touching the -ve terminal. I know it's frustrating but you shouldn't mess with these cells. This is from me, and I take EVERYTHING apart.

You may or may not know that Prometheus Lights have taken over Foursevens and apparently are selling new old stock on their site.
https://darksucks.com/collections/foursevens

Why not contact them and see if you could get hold of a disc or even some more proprietary cells?

Good luck in your quest.
P

Thanks for the further ideas. Yeah, I figured just putting a regular 18650 in there, without the disc, was a bad idea. I will refrain from experimenting.

But I'm trying to figure out if there is a reason why the person who sold me the MMR-X said the disc was not necessary and that Fourseven's stopped shipping it with the MMR-X after two years. I asked him to explain that further and he seems to have stopped responding to my messages, which I find dubious. If I don't hear anything, perhaps I will leave negative feedback, though I hate doing that.

Anyway, I sent an email to Prometheus Lights to see if they can get the disc. Thanks for that tip. I saw on Fourseven's website that someone would be taking over, but did not know that had already happened or who it was.