:) I have a few question which I hope you guys can help me clear up.
--I see there is lots of mention of protected 18650 batteries but every now and then I see people using unprotected cells in their flashlights. Under what circumstances is it "safe" to do so...? (I'm taking along the lines of eg. single cells lights/cells in series/ cells in parallel etc)
--Next I have a few 14500/AA lights on the way that I plan on leaving in the cars for "emergencies". How well do Li-ion batteries hold their charge...? (ie. how often should I take them out to have them charged..?).
--Other than the protected AW 14500s what other brands are "reliable" when it comes to 14500 batteries...?
Protected cells will self-discharge faster than unprotected ones - the protection circuit needs power after all.
The various LiPo devices I have say to charge them every 3 months whether you use them or not. You'll still have some life in the cells after 6 months, but 3 monthly charging is likely to be useful though it will shorten the life of the cells - keeping lithium cells fully charged will lower capacity and shorten life. But it means they are ready to use and most of them are essentially dead in 3 years whether they have been used or not.
I only use unprotected cells in single cell devices where over discharging them will merely kill the cell, not cause a fire. Well, apart from a very high current incandescent device that takes two 18650s and trips the protection on every cell I have. Not tried the (protected) 3100mAh cells I have in it yet as I don't use it much.
Depending on the variables , a decent cell should hold charge for months ...
I have a few 18650 that will only drop - maybe .05v in ?? 6 months [ it be a rare bird ]
Others will be almost depleted in 6 months from self discharge ...
Unfortunately its a case of buy and try , and to some extent the luck of the draw .
Protected or unprotected , bit like a condom , works most of the time ... If you feel comfortable using unprotected cells , and you are careful , whats the problem ?
In single cell lights I see little issue for experienced users
Protected batteries have a circuit that prevents over charging and over discharging (like running a flashlight until the light goes out). That's the ONLY difference. Overcharging cells can shorten their life span and/or lead to explosive venting. Overdischarging will drastically shorten their life span/capacity. Which makes them vary unstable in multiple cell lights if they're not matched. So if you can in essence be the "circuit" and monitor your cells to make sure you don't overcharge or over discharge, then unprotected cells are fine. Don't be afaid to use them but like alot of things in life, use common sense.
Well, if li-ions for flashlights are anything like li-ions for cell phones, I would say they will last at least a year to 80%. I haven't had the chance to store any 10440, 14500 or 18650 for any length of time because I used/needed them. But now that I have alot of 18650's, I'll store a few to test shelf life.
I use Trustfire flame 14500's, both pro and unpro. No issues so far.