I’m a little nervous now after reading this thread…
I frequently use my Olight S1 with wand attachment as a night light for my kids. The other morning I woke up and the flashlight was off due to the battery (CR123A) being totally depleted. Did this damage the battery or simply lower the life expectancy of the battery? Or both? Neither??
Can I use the discharged battery again?
A CR123A is a primary battery and cannot be charged.
For a rechargeable LiIon you need to check the voltage, if it is below 2 volt it is safest to recycle the battery.
Thanks for sharing your research :student:
Sorry it’s actually an 18350. Keeppower. I’ve let it run down to empty quite a few times over the last year while camping, using as a night light etc. Guess I’ve been lucky so far.
So what do you guys DO with all the batteries you’re not using right that minute? Are they in storage? If so, how do you store lights without letting them drain down too far??
I’ve got a Nitecore charger where I keep my spare 18650 or 18350s charged up so that they are ready to go when my flashlights die. Is that safe?? I believe the charger has a cutoff system that shuts off when they are fully charged.
Reading this thread makes me feel like I’ve been a bad father for almost burning my house down due to irresponsible battery parenting.
Most lights do not drain the battery when off, this means you can store the battery in the light for years.
Ask Olight tech support what is the minimum operational battery voltage for your flashlight. If 2’5+V, nothing to worry.
Store batteries where you know no moron would touch them.
Minimize battery stress keeping their no-load voltages well below the specified maximum (I’d say at or below 14/15th of this value) and, of course, not too low. Between 40-50% of SoC (state of charge) is said to be optimal for this purpose, which should correspond to around 3’77-3’85V… but heck, no need to be so anal on this, just aim at around slightly above nominal no-load voltage and you’ll do fine.
My last li-ion battery shipment tested exactly 3’8V on my multimeter.
Storing batteries on a charger is generally unwise, to my knowledge lots of them have some kind of ghost drainage which could kill unprotected batteries if kept for long enough :person_facepalming: (it could be a very looong enough, though).
Advice
At this bargainly price, do yourselves a favour and get one:
DT-830D for 3½ bucks at Aliexpress
Cheers
Thank you salvadore. Too had we cant program phones to stop charging at 80% and shut down at 10% rethought monitoring them
As I said, there’s really no point in preventing your device battery state of charge from falling below 10%, unless you deliberately do so in order to still have some power left in case of emergency.
Device manufacturers know what they’re doing: your stuff’s battery will never get damage no matter how many times it does a forced 0% shutdown. Every bit of this I already explained above.
Cheers fellas 
Keeppower has a protection circuit at the bottom so you cannot harm it by emptying it fully. Just keep on using it as you do.
That is if it is NOT an IMR battery! They do not have the protection.
Take a look at these:
MOS DIY 26650 Battery Protection Board
4.2V Dual MOS DIY 18650 Battery Protection Board (5-Pack)
The 26650 board has 2 additional slots where you could solder additional 8205A’s, for up to, at least, 8A sustained and 12/16A peak current delivery.
Cheers
Do you mean 16340 (RCR123) or 18350? I’m using the Olight 16340 in mine and didn’t think 18350 would fit… Sorry for derailing thread…
I did do one runtime test with the S1 till the protection kicked in. Was tempted to do another runtime test at another level, but then didn’t want to run the battery all the way down again.
I do not remember to have said I used just ⅓ of my battery capacity. I, generally, charge up to 60% of my maximum battery capacity so, in essence, that means I, at most, charge my device twice as much, all other conditions equal. Battery life expectancy, as said, potentially cuadruplies.
You could still benefit from a good deal of extra life expectancy (nearly 3x) by going up to about 72-74%, maybe.
With regards to the added wear on the USB jacks, I can buy a 10-pack of ’em for a buck or so (I have around 4 jacks lying somewhere on a bag, tinkerer I am). I am quite dextrous wielding my quality JBC soldering iron, and I have plenty of solder wire, cables and stuff… :cowboy_hat_face:
Hope this is adequately understood.
Cheers my dears
They are 16340 actually. Sorry for the confusion. Sounds like it’s protected so I’m not as bad of a battery parent as I thought!
Could someone please present the discharge charts for the following two batteries? 1) NiMH 3 cell, 3.6 volt, 930 mAh capacity and a load of 500 mA. 2) Lithium-ion 3.7 volt cell, 800 mAh capacity and a load of 500 mA. I would like to comapre the voltage of the two batteries as they drain. Thanks
Reviewer and tech wizard HKJ may be of help here. His website, https://lygte-info.dk, hosts thousands of battery reviews. Your question is too generic, there are lots of different possible batteries meeting those scant specs. A 930mAh cell could be some Ni-MH AAA, or some rugged long life industrial Ni-MH AA. Various 14500 (AA size) cells meet 800mAh li-ion capacity spec. And there's more.
Cheers :-)
Guys for Samsung 18650 30Q when do you charge them?3.6 or lower volts?
One more question if you put them out of the flashlights and store them which is the recommended voltage for storing li ions lets say for an year?
3,6V would be recommended yes.
Actually, 3,4V would be even better since self-discharge is even lower at this voltage.
Just check their voltage every few months just in case.
I wouldn’t worry about self-discharge on a cell in storage or in a flashlight with no parasitic drain. I have 50+ 18650’s stored away that were at about 3.6v 5 years ago and some that I pulled last year were still around that.
If anyone wants to know how far a cell can be discharge and still perform well I recommend reading this entire thread.
I read a lot of datasheets with lots of opinion’s on the web and I have personally tested a lot of cells.
The thread above goes against everything I had read or was told. Not to say the datasheets are wrong but no data on what happens if the cell is subjected to outside of those specs. It’s a must read for battery Guru’s. 
Thanks for the info HKJ. :+1:
I also still have the batteries in that thread at 10 years old now, I may do a discharge test just to see where they stand.
Anyone else still have some of these?
bluereidon, charge your batteries when you see fit. I usually do it below ≈3.6V, to always have some juice left.
Li-ion cell over-discharging is something I do not worry about. 2.5V is a frequently used and perfectly safe figure, even 2V for some chemistries. Those numbers can be found in top OEM cell datasheets.
I've recharged cells which were somewhat below 2V, from laptop packs. They can still work after this but I advice to keep them quarantined while whatching their self-discharge rate.
To me, the over-discharge thing is a busted myth, of course thanks to wisdom and discernment. 
What really “hastens” battery/cell degradation is high voltage, and what I mean here is you can noticeably increase the number of useable cycles and life span by reducing the charge voltage. See BU-808: How to Prolong Lithium-based Batteries @ Battery University.
:-)