Proto2 worked fine with button-top unprotected cells. However, proto4 only fits flat-top unprotected cells. I think this is caused by the known issue with the driver being in the wrong spot, and it should be fixed by correcting the driver fit.
It’s supposed to fit like this… which is how both proto1 and proto2 were made:
… but proto4’s driver cavity wasn’t made quite big enough, so it ended up more like this:
I hope it’s clear from the diagram why this could cause issues with battery length. Restoring that part to how it was in earlier prototypes should fix it.
Welcome to the world of lithium batteries where there are no standards when it comes to the physical size.
Unprotected flat top cells are recommended because button top may or may not fit. This was known information for many many months. In post #1 it says the maximum battery length is 66mm. If you have several button top cells then there is a chance some will fit and some won’t.
Unprotected flat tops, on the other hand, will all fit which is why they are recommended.
At first I thought you were talking about Bluzies review where a flat top battery did not fit, but that review was 3 weeks ago and was talked about here already.
I don’t normally even buy button top cells. It is much easier to make a cell longer than it is to make it shorter. It would be nice if it fit both for the sake of those who don’t want to go monkeying around with their flat tops or, invested heavily in button tops.
The battery tube length is locked in. It’s a very narrow range of lengths due to the double tube design and both tubes have to have good contact for good functionality.
It’s quite possible Neal will offer the light with the option of a good flat top cell. I have zero concerns about the battery length.
Which “review” are you referring to?? Please provide a link. That information is not correct. The length of the battery tube was not the issue.
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Nope, not a “glaring oversight” at all. See above & see TK’s detailed explanation quoted below outlining the suspected real problem.
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Hopefully you will not have to deal with disappointment. Hopefully your particular accumulation collection of high drain cells will work just fine.
But, even in a worse case scenario (which seems extremely unlikely); the FW3A just holds one cell. So, in the very, very, very unlikely event of “worse case scenario”; hopefully you will be able to deal with the disappointment, get one or two cell that fit, & be at least moderately happy with the cool new FW3A. :+1:
Thanks for the illustration of where the real problem lies. I had not seen that diagram, and probably never would, due to the time required to read through 7400 posts. Just for the record, I’m not lazy - I did read every post in the D4 review before buying, and also every post (to date) in the D4S thread, though I haven’t bought that one yet.
The issue seems to be simply a matter of paying more attention to the size tolerance of the various parts, which hopefully the manufacturer will address before beginning production. But yes, it would still bother the heck out of me to see so much good work go into this project and then have the versatility crippled by poor manufacturing.
Are you still not sure if I am serious or kidding? Since you didnt respond to my post explaining the cap clip, I was not sure if you just didnt understand what I was trying to do or maybe there was something wrong with the design that would keep it from working……… maybe it is a good design but without explanation your reply suggests otherwise.
It looks like it would work on a baseball cap, if it’s not too heavy, but wouldn’t work very well in most other places. If I had one I would probably take the clip off, or maybe break off the extra fold.
TK, since no one from Maukka’s review has asked here yet, can you tell us why the two battery tubes in the FW3A can not be equally lengthened 0.5mm to 1mm so as to make it fit both flat top and button top batteries?
(Right now it only fits some button top, but not all. Max battery length is 66mm)
I figure there must be a reason and it was probably determined over a year ago, but people where asking and I don’t know the answer.
It’s mostly just too late, and would risk making shorter batteries lose contact when bumped.
Also, I think Lumintop may have only a compiled version of the 3D model, without any way to modify it. They might need the original from Fritz instead of an exported / compiled version. I’m not sure about the details though.
I'm surprised this has even come up. High-drain cells are flat-top by default. Button-tops are weird and abnormal for high-drain, unprotected cells. (I actually had to be very careful buying batteries for my L6 for this reason!)
Aren't most super-compact lights advertised similarly, some kind of "unprotected/flat-top only, others may not fit"? My Zebralight SC62, Lumzoo GH10, and Emisar D4 all have battery fitment concerns. Two of those aren't even high-drain! I'm sure we will get reviews very quickly in which members measure very precisely and test with a variety of cells, between protected and not, button-top and not.
I increased the available inner length of four Utorch UT01s by simply adding a snug-fitted circle of copper wire inside the tailcap, such that it makes full contact with the end of the tube. Takes five minutes, and works like a charm. It’s a very easy way to add a couple of mm’s.
I suppose this light might be somehow structurally different to prevent that from working, but it’s one potential fix if length is a problem.
No, no, it makes no difference if it’s a high drain or low drain or high capacity or whatever. All the 18650s from the “Big 5” Japanese companies (Sanyo, Panasonic, Sony, Samsung and LG) only come as flat top. It is the distributors that will add the button top which is why there are so many different sizes and styles of button top.
Now if your talking about any other battery company, then the sky is the limit and anything is possible. You can get 18650 batteries made in smaller factories as well as all different sizes, top configurations and protection circuitry. Some smalker companies will even take a Big 5 battery and rewrap it with and without a button top and/or protection circuitry.
There’s no way to do that on the FW3A that I can see. There’s no need for it either. Just use a flat top. I bet Neal will offer it with a battery installed like he did with other lights. At least I hope so.
A good flat top like a Samsung 30Q or 35E should only cost $5. I don’t see the need for anyone to get worked up over this battery.
I don’t have an FW3A. However, I suspect it would be possible to mod the light for extra length providing there are sufficient threads to allow it to be unscrewed enough and still hold together.
However, it would take some experimentation and would certainly take a lot more than 5 minutes.
A single c-ring created from wire or a narrow copper ring would not be sufficient. You would need 2 rings: 1 for the inner tube and one for the outer. And they would need to be separated by some kind of insulating material. Kapton tape or maybe Arctic Alumina epoxy.
These rings would need to be roughly the same thickness as the stock body and inner tubes with a similar gap between. They would also need to be the same height. Get it wrong and the switch won’t work right.
Easiest way to do it is probably to:
Cut a very thin uniform length from a copper sheet. Try to make it as narrow as possible. Maybe 1-2 mm thick.
Cut the strip into 2 separate pieces.
Bend each strip into a C-ring. One for the inner tube, one for the outer. Test for fit.
Run a couple strips of kapton tape along the transition between the two tubes. Maybe super-glue it in place.
Super-glue the other other tube to the top of the kapton tape.
Use a knife and trim off any kapton tape sticking out the top or bottom of your c-ring sandwich.
File the top and bottom of the rings so they are completely uniform.
If necessary to maintain good battery contact, replace one of the stock springs with a longer low-resistance spring.
