TBeam Battery Size

Hi folks. Bought a TBeam, bought separate batteries. The battery I have won’t fit. I think I did something wrong. Bought TR 18650 3.7V batteries, but very difficult to get into the holder, and I don’t want to break anything.

Battery length: 67.5 mm

Anybody know what I’ve done wrong? Any insight appreciated. Cheers

It is a very tight fit, slowly wedge it in.

I have found that there are different sizes of these batteries. I’ve ordered a 65mm smaller size. Cheers

just measured mine and they are 65mm and fit tightly.


Ya mine is larger than that. It’s 67.5 and apparently has a protection circuit up top, which makes it larger. I’ve never heard of batteries having multiple variations on a single part number.

I ran into this. I just took a razor and very carefully cut the plastic wrapper off the battery, and then removed the protection circuit (it was spot welded on, and easy to remove with brute force).

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Oh that’s wonderful. I have a new one on the way, so I’ll wait until it gets here. I have a superb flashlight that came with it (save money) so I will compare them. Cheers for that. This needs to be documented somewhere.

New battery arrived. Noticeably shorter. Tight, but it fits. Cheers

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I have used pliers to carefully squeeze the contacts on the battery holder to allow 18650 cells that have the bump (are not flat) to fit. Never had a problem with battery width.

OK but to be sure, would have to measure ultimate length.

Yeah, there’s “button top” and “flat top” 18650’s out there, and unfortunately, no one bothered to specify the difference in the t-beam specifications.

I have two button tops with different lengths. I’m just amazed that this is a thing.

The actual 18650 spec is 65mm long (that’s what the 65 in the name means). They are flattops and this is what you get from original manufacturers like Samsung, Panasonic, and Sony.

Unfortunately, the world is full of 3rd-party brands that rewrap the original cells and add their own stuff. These cells may be out of spec by up to 5mm in some cases. Original manufacturers also never sell direct to consumers; they are strictly B2B components. So we are at the mercy of the resellers.

The battery holder in TBEAMs appear to be original 18650 spec.

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Searching for an 18700 battery holder as many of the flashlight versions of this battery are longer (especially with onboard BMS / USB ports for charging). Ordered an NCR18650GA that is the proper size.

I got a USB version charger with sliding bottom terminal.

hi folks,
how about 18650 protected and not-protected versions of cells?

It’s all in the thread. Protected cells are taller.