That’s what I figured. I saw a post from Lumintop on the board claiming their cell with the built in port is only 2mm taller than a protected cell, of course taken with a grain of salt since it’s coming from Lumintop themselves.
Are these cells even still popular? Seems hard to find them for sale. Is there a go to brand?
Not that I know of. I have a variety of ’em that were come-with cells, like from Nitefox, Wuben, etc. I don’t even pay attention to which is which, as I rarely “have to” use them, and mainly just keep ’em around in case I want to gift a light to someone who may not want to bother with a separate charger.
The issue is not the USB port, its that they are likely protected. The protections circuit is what makes them longer. My S2+ wont take protected batteries. They stick out of the body about a 3/8 inch. So I use unprotected with are considered better (by many BLFers.)
The USB port makes them longer than any other battery. I’ve had some from wowtac in S2+’s for a few years. The springs on both ends are definitely fully compressed but they work. I don’t know that I would recommend it though because there is zero room for error.
Here’s an interesting wrinkle - I have some 70mm Epoch 18650 cells with USB charging. In my 7135 lights purchased late 2019 the cells allow the light to barely close and do not actually work. In the FET lights with new square thread purchased late 2020 the cells fit and function fine.
Newer, FET driver, square thread on the left. Older triangular thread, 7135 driver on the right.
I think what’s making this topic confusing is that there is no standard of dimensions between manufacturers for these cells. They all seem to differ, and seem to take a different approach. Nitecore makes one with a significantly less capacity, maybe they reduced the battery capacity so the cell occupies the same space as a standard 18650. Whereas we can clearly see from HKJs thread that other manufacturers just added the circuit on top of a pre-existing 18650.
HKJ did a dissassembly review of these of these “USB cells”, I believe the protection circuit and charge componenets on these cells are on the same PCB that holds the micro USB port, so I’m not sure that is correct? I’m positive the Micro USB port does add some height overall. Maybe that’s the 2mm Lumintop quoted, 2mm over their protected cell. Which makes sense. Will try to dig out that post.
Also, yes I understand why most BLFers prefer unprotected cells, and agree for the most part they are better. But for this application, I need the light to be “travel” friendly where I don’t have to carry extra equipment (ie: charger). I will already have a Micro USB cable and USB power supply with me wherever I go for charging phones and other devices that will be with me.
Thanks for the pictures spoonrobot. Provided these cells are still popular and not all discontinued, I’m sure I can make it work.
I know Nitecore still makes them. Have to look more into what supply is still out there, and if this is a long term solution or perhaps these cells are going the way of the dodo…
They all start with a standard length flat top battery. I pulled one apart a few weeks ago rewrapped by Night Provision 2600mha. It had failed a couple of months ago and I finally yanked the top off to see what was going on. It wasn’t the charging circuit that had failed. There was a bunch of rusty crusty something that had apparently bridged the gap at the flat top and outside shell and shorted the cell out. Probably very slowly, so it wasn’t a massive hot mess. But the cell is totally dead and I’m not going to try to jump it. I’m not sure what caused the rusty crusty though. Maybe I’ll cut the rest open to see what the inside looks like.