Ok, here's the answer I got from buGG, the electrical guru, regarding the unprotected 14500s (as you can see, the guy really knows his $#!+):
Re: Unprotected 14500 battery issue
the included protection circuit of the device [DSE905] is a good idea, but how well it works or whether it works at all are really unknown until something goes wrong. i wouldn't count on it here, but that's not to say that protected batts are necessary either.
in the 14500 battery i only recommend one model, the AW IMR14500, available here:
AW IMR 14500 LiMN Rechargeable Lithium Battery
the reason being is because even though this cell is unprotected, it is made from a chemistry far safer than the conventional li-ion batteries, those with a protection circuit or without; if either battery fails only the IMR battery will not vent with flames and explode. the protection circuit of other li-ion batteries is good mainly to prevent overcharging and over discharging. most chargers are going to account for overcharging of the cell regardless, and with an IMR battery you will know when you need to recharge it because you won't get any more vapor from your atomizer. at that point, the battery still has a significant charge in it to be placed back on the charger and get back to tip top shape. if you were to vape with an unprotected li-ion cell until you couldn't get any vapor, the cell would likely have permanent damage. recharging a cell like that would cause it to swell, cause gas build up, and seriously increase the chances of battery failure and explosion. that's why protection circuits are really helpful, but with the IMR, used with any atomizer, you'll know well before the cell has dropped to unsafe voltage levels, generally below 2V.
the other thing is that the AW IMR14500 is the only battery in that size category that can handle all the atomizers that we currently use, be they standard or low resistance. any other battery will fail to meet the amp draw of a low resistance atomizer, most of them will fail to meet the amp draw of standard 510 and 306 atomizers, and many will fail to meet the amp draw of all the rest. this doesn't mean that the atomizers won't work, it just means that because the atomizer wants more current than the battery is capable of providing continuously, the battery becomes stressed, there is occasional voltage sag, and the overall runtime and lifespan of the battery will decrease.
so be sure to tell the other forum member, regardless of the mod they choose, and regardless of the atomizers they choose to use with it, to start off right and grab the AW batteries.
AW LiFePO4 3.2V cells for 6V mods (safe chemistry like the IMR),
and then the following for any 3.7V or 7.4V mods that will accept them:
AW IMR16340
AW IMR14500
AW IC17670 (protected)
AW IMR18500
AW IC18650 (protected)
