How far can LiIon be discharged?

Draining slowly mean the battery spends more time at the lower voltage, i.e. more damage.
But as I say above the 2.5V or other end voltage is not the danger limit.

Well, I’ve barely read a thing about those Nyquist plots, yet anyway, that explains “everything”. Thank thee. In such a case, that just confirms (my) the predicted safety of using single (1SxP) buck driven li-ions led flashlights because of their minimum (led) Vf, which coupled with the intrisically higher internal impedance of the battery when approaching that low Vf… means it is even more difficult for the battery to reach “that low”. Hope this is understood my dears. :laughing:

Cheers

What would your advice then be for discharging phone batteries to ensure a proper calibration of them?

For instance, I am using an iPhone 6 Plus. I read that the battery should be completely drained once per month. However, I read online that it is unwise to completely discharge the battery (run the iPhone on max brightness and play a video with max volume till it shuts off).

I, for now, don’t let my battery drop below 10. I just wonder how I can fully calibrate it by letting the capacity of the battery drain fully so I can charge it from 0-100 and have the highest accuracy of calibration for the said battery.

You only need to calibrate it if your believe the remaining time is far off.
A full discharge/charge will allow the fuel gauge to recalibrate itself, these chips are counting mAh into and out of the battery and this will go out of calibration over time. Some of the newer chips can also correlate with battery voltage and do not need much calibration.

I’ve not done a “battery calibration” for months on my XT1032, and still it shows me accurate enough charge estimations… :sunglasses:
I minimize battery wear by not charging it above 60%, generally. See here:
BU-808: How to Prolong Lithium-based Batteries
Additional information: in the article it is reported that, for 4’2V maximum voltage li-ion chemistries, 3’92V or below no-load voltages are reported to do away with all voltage related stresses. 3’92 / 4’2 equals 14/15 so I’d use this fraction to determine/estimate this equivalent voltage for the now commonly used higher maximum voltage ICR chemistries (commonly used in modern mobile phones).

Stupid myths and [censored] seem to abound everywhere. :person_facepalming:

Your device’s battery is completely firewalled through its power management circuitry. That means in no [censored] way will it allow the battery to be over-discharged.
I bet the lowest no-load voltage your phone’s battery has ever seen is fairly above 3V. I’ve never seen below 3’1V (load voltage, which is always higher than no-load) through my battery monitoring software before a forced low battery system shutdown.
What is more: what you call a “charger” is not really a charger but, usually, just some kind of more or less capable constant voltage supply with @#$% gimmicks.
The aforementioned power management circuitry inside your device decides what/how and when whatever crap is done: “negotiates” power input with the PSU/charger for up to the required amount, feeds the device’s internals and then uses the remaining power to charge the battery.

How could they, the manufacturers, gladly offer the kind of device warranties you seem to enjoy in these iCraps, Crapdroids, Wincraps, etc. in the hands of uneducated [censored] morons without this kind of sophisticated power management? :person_facepalming:

Well, hope this is properly understood. Maybe I should write a sticky about this somewhere, for the love of @#$%…

Regards,
Salvador

Yes, I meant exactly that. According to the previously alluded article at Battery University, just around 58% of remaining battery capacity is held at 14/15th of maximum charge voltage (3’92 out of 4’2V).
My battery is a 3’8V nominal unit, and, at most, I see just below 4’33V full charge voltage. At 60%, I can guarantee you I’m obtaining 4x the estimated battery life expectancy since for every reduction in (nearly) 0’1V maximum battery voltage it is estimated the cycle count doubles. So I attain 8x the cycle life at above half of the useable battery capacity: guaranteed 4x typical battery life expectancy.
And no, it is not inconvenient for my optimized rooted system: I consistently attain above 3 hours of SoT (screen on time) with just ½ of the battery capacity.
Moto G 2013 XT1032 running stock über-optimized “Crapdroid” Lollipop v5.1.
Hope this helps. :cowboy_hat_face:

Cheers

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:

Regards,
Salvador

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.

Cheers

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).

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