How far can LiIon be discharged?

How do you get it to stop charging at a certain percent?

Thanks HJK for the info :slight_smile: it seems that the cells fall-off at the 3volt average mark then rapidly dropping to the 2.5 volt, but the rebound is quick when the load is switched off.

Yes thank you HJK. I wonder why low voltage cut off is not at 3volts? No real power left so flash lights should shut down to save the cell

That’s none of my business. :crown:
However, what they say about battery life expectancy, cycle count, etc is something which matches my (limited) own real life tests, even if these lack any validity and or credibility to you. Thus, go out there and continue using your batteries as the rest of humanity, you’ll be more avidly feeding the related research & manufacturing industry. Thank thee. :face_with_monocle:


Thank you HKJ!

It doesn’t stops; my cooked solution is to use some kind of software (Battery Monitor Widget) to trigger an alarm when certain conditions are met, so I exactly know when to unplug the PSU brick. In this case:
batt% >= 60 AND Plugged

An added benefit of my policy is that I can minimize the time I have to spend “plugged” because my device nearly always charges the battery in CC mode as, at these charge estimation levels, maximum battery voltage is never reached and thus charge current flow is never dampened.
Most efficient battery management policy. Period. :cowboy_hat_face:

For the sake of completeness:

Hope this helps.


Thanks a lot HKJ, article Sticky’d.

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).

At this bargainly price, do yourselves a favour and get one:
DT-830D for 3½ bucks at Aliexpress


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 :crown:

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.


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!