Disposable vape designed to easily remove its 520mAh Li-ion rechargeable - Page 1
Forum section: electronics / projects

author: RoGeorge
author_rank: Super Contributor
timestamp: May 14, 2025, 02:17:54 pm
content: Few days ago bought a single-use vape for a former smoker. Though, even the vape is a disposable/single-use, on the box it says "Removable Battery".That was a nice surprise, because usually a disposable vape has a rechargeable Li-ion batteries inside, but the battery is very hard to remove. Often, the only way to remove the battery is to tear/cut/break the body of the device.This model has by design a twist-to-unlock the bottom mechanism, such that the battery can be removed repeatedly. Looks like a very reliable battery door. Inside, there are nice golden springy contacts to the battery (both contacts are on the same end of the battery). Also, the body/enclosure is made out of a metal cylinder (good as a shield, in case you want to reuse the vape body + battery assemble to host a DIY circuit).Apart from the battery lid, rest of the parts are press fitted into the metal cylinder. The mouth muffle can be pulled out without any tools and without any damage, by strongly wiggling it left, then right, and so on, with both hands. The rest is fit with rubber seals, and the heater can be dismantled too (has 2 sideways plastic clips easily visible). Out of all the disposable vapes I've seen, this was by far the easiest to dismantle.Vape brand is "blu bar"?, and the battery type is KFC 16300, 4.2V Li-ion, 520mAh (1.92Wh at 3.7V).On the battery it is written "Do not recharge", so I guess it's a raw Li-ion cell, with no protection/BMS/fuse on it.Though, the battery is rechargeable (I've tried, and it can be fully charged to 4.2V top while limiting the current to only 100mA, will measure its real capacity later). Make sure to not overcharge/to not overdischarge/to not short-circuit the battery. Best will be to add a small Li-ion protection board (single cell protection board for Li-ion, sometimes called single cell 4.2V Li-ion BMS, can be bought separately).Writing all these because such a disposable vape seems just right to host an active probe, or some other DIY electronic device.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 14, 2025, 03:12:09 pm
content: For the docs, there is a video about this exact same model:Easiest free street-lithium yet - with gold flashed contacts!bigclivedotcom(I didn't solder on the battery as in the video, used the existing springy golden contacts instead).Found, too, a reddit thread about the "Do not recharge" printed on the battery body:https://www.reddit.com/r/batteries/comments/1k5fcs1/are_they_really_not_rechargeablekfc_13350/

author: amyk
author_rank: Super Contributor
timestamp: May 15, 2025, 01:50:14 am
content: There are suspicions from others that such cells may be either ones that got rejected during factory testing as having a very high rate of degradation upon being recharged, or otherwise use substandard materials not suitable for cells sold as actually rechargeable, i.e. basically a way to make a profit from recycling.Yours is actually in a capacitor-style can, and has two leads, but they soldered those to a PCB to provide coaxial contact rings.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 15, 2025, 07:23:39 am
content: About the self discharge-discharge rate, the vape has a 1 year shelf-life. So, I guess the self discharge rate can not be too bad, or else the battery won't last until all the liquid is vaped. Must be something else.My guess is they written the "Do not recharge" warning because the manufacturer doesn't want to take responsibility for long term reusing of the battery. Since the battery is removable, some might got the idea to recharge the battery using random chargers, which might start a fire.Casual removable Li-ion batteries (like the mobile phone batteries, or the 18650) have an internal protection board, while this one has no fuse and no protection against overcharge, overdischarge, overcurrent or reversed polarity. Beware of that!Preferably would be to add one of those small circular breakout boards with a Li-ion protection circuit. Also, don't let it unattended while charging, preferably use a fireproof place, or container, or pouch, etc., the usual measures while handling Li-ion cells.For now, I've only recharged it using a Rigol DP832 CC-CV power supply set to limit the charging current at 104mA (0.2*520mAh, aka the typical 0.2C), and the max charging voltage limited at 4.2V (the 4.2V is written on the small paper leaflet found inside the vape's box).By the amount of energy taken during its first recharging, this battery looks no different than any typical 500mAh Li-ion rechargeable.I've logged the I and V. Will post some plots after a few charging/discharging cycles.

author: sleemanj
author_rank: Super Contributor
timestamp: May 15, 2025, 08:17:59 am
content: QuoteMy guess is because it has no protection circuit on the battery that they don't want clueless people recharging it and burning their house down.I doubt that there is anything "wrong" with the cells in vapes, indeed it's a pretty high-demand environment, so I could imagine that they are actually quite well spec'd for low capacity cells.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 19, 2025, 03:37:38 pm
content: These are the measured charge/discharge curves:Charging was topped at 4.2V, but it was kept connected for longer than it should (left it connected all night to a DP832 power supply set for 104mA/4.2V).I have 2 batteries (from 2 bought vapes, battery date is only one month apart, cca 2024-06), one measured 605mAh, the other 564mAh. Charge/discharge was made at 0.2C constant current (104mA). Both were showing more than the nominal 520mAh written on the battery. The attached plots are for the battery that mesured more.About the "Do not recharge" printed on the battery body, the only difference I can spot from other casual Li-ion cells (from example compared with mobile phone batteries), is a slightly higher voltage for the discharging plateau (about 0.1-0.2V more). Maybe they are 3.8V nominal and 4.3V max, like I've seen to a few models of Samsung phone batteries.It was possible to discharged them down to 2.5V, so they seem to be unprotected, raw Li-ion cells.Side note, the open voltage was more than 3.5V when removed from their empty single use vapes.