How far can LiIon be discharged?

48 posts / 0 new
Last post

Pages

HKJ
HKJ's picture
Offline
Last seen: 11 hours 59 min ago
Joined: 05/24/2011 - 12:23
Posts: 5204
Location: Copenhagen, Denmark
How far can LiIon be discharged?

How far can LiIon be discharged?

title

I do often see a question about how far LiIon can be discharged and if it is safe to charge a discharged LiIon. These questions can be fairly difficult to answer precisely, LiIon manufactures do not publish much about it and LiIon is not just LiIon, there are many different chemistries with similar but not equal specifications.



How to measure the discharge cut-off voltage?

Some people do not wish to discharge below 3.6 volt (or something), but why stop there when the specifications say 3.0 or lower?
There is some sort of reason for this and it has to do with how you measure voltage: Usual voltage is measured with the battery out of the equipment, i.e. the battery is unloaded. Here is an example:

Panasonic%20NCR18650A-discharge-2.0

Here I discharge a cell to 2.5 volt with 2A, when I stop the voltage jumps to 3.3 volt and it jumps fairly fast.

Panasonic%20NCR18650A-discharge-2.0zoom

Zooming in on the stop, the curve shows 3 minutes. It takes 12 seconds for the voltage to raise from 2.5 volt to 3.1 volt. This means that if you take the battery out and measures it you will never see the 2.5 volt.

Samsung%20ICR18650-26F-discharge-2.0

Lets try with another cell.

Samsung%20ICR18650-26F-discharge-2.0zoom

This is also a 3 minute view, the voltage raises from 2.5 volt to 3.1 volt in 3 seconds and in 7 seconds it is about 3.2 volt. Again it is not possible to measure the voltage where the equipment turns off.

How far the voltage jumps depends on the discharge current, a lower current will give a smaller jump and on the battery chemistry, different chemistries gives different voltage jumps. This means that measuring voltage with the battery out of the equipment will not give a correct indication of the minimum voltage the equipment discharged the battery to.

Due to the above jump in voltage it is rather difficult to know what the actual battery voltage is inside the flashlight when it is on and the safe way is to assume it is empty when the unloaded voltage is below some value. The 3.6 volt is fine for some batteries, but it is possible to go lower with many modern cells as seen above. The table at the end of the remaning capacity article can also be used.



How far to discharge batteries during normal use?

The first answer to this is easy, check the datasheet:

DischargeVoltageDatasheets

Here are some values from 4 different datasheets. The most common values are 2.75V and 2.5V today.

These values are the lowest voltage that is allowed on the battery if the full lifetime must be reached*. This means that for any normal usage this is the lowest value to discharge the battery to. This voltage do not include any current, i.e. the limit is not one that can only be discharged to at high currents, it is allowed to discharge with a very low current to this specification.
It is not within specifications to discharge below this voltage, just because the battery will recover to above this voltage when the load is removed.

*Usual, the 2.0 volt specification is not used for lifetime tests on that cell, there the lower limit is 2.5 volt.


But my over-discharge protection do first trip at 2.3 volt, is it faulty?

Usual no, protection is normally not used, i.e. it is allowed to go outside the range for best lifetime.

MinDischargeVoltage1

Here is some data from Samsung, the over-discharge protection is supposed to be outside the normal usage range.

MinDischargeVoltage2

And if I include a bit more of the table it can be seen that it varies with application. At high current the protection can be at a lower voltage.
From this table it looks like it is acceptable to discharge LCO/LMO (Real ICR/IMR) cells below minimum value, when it is done at high current, but with the more modern cells it is best not discharging too much below rated voltage.



How low voltage is safe to recharge?

Here are some illustrations from LiIon handbooks:

VoltageRange

VoltageRange2

In both illustrations there is:
Operating range, that is the voltage range from the datasheet.
Protection/safety range, that covers a wider voltage range, but may add extra wear to the battery.
Keep out/unusable range, that is very low or very high voltage and the battery is dangerous.

DoNotCharge

The Samsung guidelines also list a minimum voltage.

These 3 items gives the minimum voltage as 1.5 volt, somewhere below 2.3 volt and 1 volt. This covers different brands and different chemistries.
Another importance detail is pre-charging, when the voltage is low the battery must not be charged at full current. A reduced current must be used.
When a battery is discharged to this low voltage it may lose some capacity and will lose some lifetime.

The reason to not charge very discharged batteries is because the chemistry breaks down at low voltages, depending on how much the chemistry has degraded the battery may explode when charged!



Conclusion

With the above as basis I will recommend the following:
1) Do not use over discharge protection as signal for when to charge batteries, it might wear the batteries down faster.
2) Do not charge batteries measuring below 2 volt, except if you have data saying it is safe.
3) When cells are down to 3.3 to 3.6 volt unloaded they are empty according to my tests, when the load is a few ampere.
4) Just because the cell recovers voltage, do not make it advisable to discharge below the limits while current is on.

And remember that if a battery gets hotter than usual during charger and/or will not charge fully (i.e. charger will not terminate), it is dead and maybe dangerous.



Notes

This article uses excerpts from:
Lithium Ion Rechargeable Batteries Technical Handbook (Sony)
Lithium Ion Batteries Technical Handbook (Panasonic)
Pack Design Guideline (Samsung datasheet, I have done some cut and paste in the table)

More voltage jumps with and without load

My website with reviews of many chargers and batteries (More than 1000): http://lygte-info.dk/

Edited by: sb56637 on 04/15/2016 - 12:01
CRX
CRX's picture
Offline
Last seen: 5 hours 7 min ago
Joined: 04/02/2013 - 15:27
Posts: 1825
Location: Scotland

Thanks. Beer

will34
will34's picture
Online
Last seen: 7 min ago
Joined: 12/18/2012 - 00:12
Posts: 3107

Thanks! very useful info.

everydaysurvivalgear
everydaysurvivalgear's picture
Offline
Last seen: 38 min 19 sec ago
Joined: 07/31/2015 - 10:25
Posts: 2316
Location: sydney australia (GMT+10)

Hey mate correct me if im wrong but if the battery says 2.8 volt cut of for example you need to reach that voltage to get the advertised mah?

HKJ
HKJ's picture
Offline
Last seen: 11 hours 59 min ago
Joined: 05/24/2011 - 12:23
Posts: 5204
Location: Copenhagen, Denmark
everydaysurvivalgear wrote:
Hey mate correct me if im wrong but if the battery says 2.8 volt cut of for example you need to reach that voltage to get the advertised mah?

Yes, but depending on chemistry and current you might get very close at higher voltage. The rest of the way down to 2 volt will only be few mAh, but will increase the wear of the battery.

My website with reviews of many chargers and batteries (More than 1000): http://lygte-info.dk/

Mitko
Mitko's picture
Offline
Last seen: 1 day 12 min ago
Joined: 09/19/2014 - 05:20
Posts: 1457
Location: Bulgaria

10x m8,

I just watched a Discovery documental movie about telecommunication satellites, they stated that some of those use LiIon batteries( they didnt mentioned what type) : they never charge the LiIon pack over 65% of its potential, and nevel let it go down under 30%: thus the pack coud be recharged over 80k times! I was quite impressed realy

chadvone
chadvone's picture
Offline
Last seen: 2 months 1 week ago
Joined: 08/28/2015 - 23:48
Posts: 622
Location: Iowa

This thread should be a sticky. Maybe a title change, so it doesn’t look like a question.

Zero

1dash1
1dash1's picture
Offline
Last seen: 1 year 1 month ago
Joined: 08/29/2015 - 22:02
Posts: 1576
Location: Hilo, Hawaii

Thank you for summarizing and providing references for us!

The discrepancy between battery voltage under load (with the flashlight turned on) and the rebound voltage measured after pulling the battery out had always been a nagging issue in the back of my mind. Your explanation helped clear that up.

And caused me to re-think my charging/re-charging practices. In the past, I targeted 3.0V (resting) as being the minimum I’d like to see my battery levels when recharging. However, if the rebound voltage is 3.0V, then the voltage under load might have been somewhere under 2.5V – not good! So, that means I’ll need to adjust my target level to something more like 3.3V or 3.4V.

Rule 1-1 as it applies to life, take it as it comes.

HKJ
HKJ's picture
Offline
Last seen: 11 hours 59 min ago
Joined: 05/24/2011 - 12:23
Posts: 5204
Location: Copenhagen, Denmark

chadvone wrote:
This thread should be a sticky. Maybe a title change, so it doesn’t look like a question.

Zero

I like my titles to match for all places where I publish. This is not the first article with a question in the title, there is also this one: http://budgetlightforum.com/node/45344 about low charge voltage, it was from there I got the idea for this article.

Anyway people looking for information will probably open a thread with a question title, to see if it has a good answer (At least I hope so).

My website with reviews of many chargers and batteries (More than 1000): http://lygte-info.dk/

MRsDNF
MRsDNF's picture
Online
Last seen: 9 min 19 sec ago
Joined: 12/22/2011 - 21:18
Posts: 11019
Location: A light beam away from the missus in the land of Aus.

Thanks HKJ. Again advice we should all heed.

My current and or voltage measurements are only relevent to anything that I measure.

Budget light hobby proudly sponsored by my Mastercard and unknowingly paid for by a hard working wife. 

djozz said "it came with chinese lettering that is chinese to me".

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

JakeDjanitor
Offline
Last seen: 2 months 1 week ago
Joined: 10/27/2015 - 09:00
Posts: 677
Location: North East USA

Great info! Thanks

Halo...
Halo...'s picture
Offline
Last seen: 10 months 4 weeks ago
Joined: 12/15/2011 - 02:39
Posts: 3304
Location: Halo island

HKJ wrote:
chadvone wrote:
This thread should be a sticky. Maybe a title change, so it doesn’t look like a question.

Zero

I like my titles to match for all places where I publish. This is not the first article with a question in the title, there is also this one: http://budgetlightforum.com/node/45344 about low charge voltage, it was from there I got the idea for this article.

Anyway people looking for information will probably open a thread with a question title, to see if it has a good answer (At least I hope so).


I would suggest “How far can LiIon be discharged? (detailed answer)”
Barkuti
Barkuti's picture
Offline
Last seen: 21 min 26 sec ago
Joined: 02/19/2014 - 14:46
Posts: 1455
Location: Alhama de Murcia, Spain

Thanks for this interesting data HKJ.

I've recently been giving some advice on FastTech's forums to certain users concerned about the safety of using unprotected batteries on single-cell (1SxP) buck driven led flashlights. Since the absolute minimum voltage a typical (Cree) led would drop for any current to flow is 2'5V (checked XM-L/XM-L2 datasheets), my conclusion is that it is pretty safe. It must be understood that, as we approach that voltage, current flow diminishes exponentially: it'd take “ages” to reach there (and it would be undeniable to notify on the light's output.

 

It is a bit surprising to me to see such a jump between load and “no-load” (voltmeter…) voltages in your measurements for that current flow, because that would mean there's close to 0'4Ω of resistance among:

{ R = (Vnoload - Vload) / I }

  • The battery's internal resistante (supposedly lower than 0'4Ω).
  • Whatever stuff between the battery terminals and your readout locations… ?
  • Am I missing something?

1dash1 wrote:
… And caused me to re-think my charging/re-charging practices. In the past, I targeted 3.0V (resting) as being the minimum I'd like to see my battery levels when recharging. However, if the rebound voltage is 3.0V, then the voltage under load might have been somewhere under 2.5V - not good! So, that means I'll need to adjust my target level to something more like 3.3V or 3.4V.

Hope the expounded above helps.

 

Regards,

Salvador

Copper is mine, copper divine!

Votes & comments: https://imgflip.com/i/1rwxix 

MRsDNF
MRsDNF's picture
Online
Last seen: 9 min 19 sec ago
Joined: 12/22/2011 - 21:18
Posts: 11019
Location: A light beam away from the missus in the land of Aus.

This question is asked a lot on the forum so will ask here.
If the batteries voltage is measured less than the recommended minimum does it make any difference to the chemistry and safety of the battery if its discharged below the limit very quickly or slowly, for eg in a flashlight that has very low parasitic drain?
Many are tempted and it is often mentioned that it is safe to recharge a battery if it has been drained below the recommended voltage slowly.
Hope that all makes sense.

My current and or voltage measurements are only relevent to anything that I measure.

Budget light hobby proudly sponsored by my Mastercard and unknowingly paid for by a hard working wife. 

djozz said "it came with chinese lettering that is chinese to me".

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

HKJ
HKJ's picture
Offline
Last seen: 11 hours 59 min ago
Joined: 05/24/2011 - 12:23
Posts: 5204
Location: Copenhagen, Denmark
MRsDNF wrote:
This question is asked a lot on the forum so will ask here. If the batteries voltage is measured less than the recommended minimum does it make any difference to the chemistry and safety of the battery if its discharged below the limit very quickly or slowly, for eg in a flashlight that has very low parasitic drain? Many are tempted and it is often mentioned that it is safe to recharge a battery if it has been drained below the recommended voltage slowly. Hope that all makes sense.

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.

My website with reviews of many chargers and batteries (More than 1000): http://lygte-info.dk/

gauss163
Offline
Last seen: 1 hour 36 min ago
Joined: 10/09/2013 - 18:04
Posts: 722
Location: USA
Barkuti wrote:
It is a bit surprising to me to see such a jump between load and “no-load” (voltmeter…) voltages in your measurements for that current flow, because that would mean there’s close to 0’4Ω of resistance among:

{ R = (Vnoload – Vload) / I }

  • The battery’s internal resistante (supposedly lower than 0’4Ω).
  • Whatever stuff between the battery terminals and your readout locations… ?
  • Am I missing something?

Yes. The internal resistance increases immensely when the cell is near empty. You can obtain a better understanding of the full impedance spectrum by perusing Nyquist plots (search on those buzzwords to find expositions on this and related topics).

gauss163
Offline
Last seen: 1 hour 36 min ago
Joined: 10/09/2013 - 18:04
Posts: 722
Location: USA
MRsDNF wrote:
This question is asked a lot on the forum so will ask here. If the batteries voltage is measured less than the recommended minimum does it make any difference to the chemistry and safety of the battery if its discharged below the limit very quickly or slowly, for eg in a flashlight that has very low parasitic drain?

Yes, the more time the cell spends in any “danger zone”, the more time undesirable internal reactions have to cause degradation. For example, if you discharged a cell at 1 amp and it hit 2.0V, then it may have been in the dangerous zone between 2.5V and 2.0V for only milliseconds, so only miniscule degration will occur. But if instead it drained from 2.5V to 2.0V from self-discharge while in storage then that may have taken many months, so the damaging internal processes will be running for much longer, potentially causing much, much more degradation.

gauss163
Offline
Last seen: 1 hour 36 min ago
Joined: 10/09/2013 - 18:04
Posts: 722
Location: USA
everydaysurvivalgear wrote:
Hey mate correct me if im wrong but if the battery says 2.8 volt cut of for example you need to reach that voltage to get the advertised mah?

The manufacturer rated capacity is quoted under precise conditions usually specified in the datasheet, namely at a certain constant current discharge rate (usually around C/5), at a certain termination voltage, at a certain temperature, after a certain type of charge and rest period, etc.

If you change any of those parameters then it may change the measured capacity. For example, if you discharge at a higher rate (with all else the same) then you will typically measure lower capacity, esp. if the cell has high IR (internal resistance), because the higher current will cause a higher IR voltage drop, pulling down the discharge curve so that it hits the termination voltage sooner. To access the remaining capacity you will need to discharge at a lower current (to stay above the termination voltage).

If you examine a typical Li-ion discharge curve then you will see that the voltage drops much more quickly after it gets past its “knee”, when the battery is near empty. Thus little energy is provided in this region. So if you keep your termination voltage to voltages after the knee then the capacity changes relatively little. But if you terminate at a voltage in the earlier part of the curve before the knee then there the curve is more flat (smaller slope) so a small change in voltage corresponds to a large change in time, so a larger amount of energy is lost by premature termination in the range before the knee.

Barkuti
Barkuti's picture
Offline
Last seen: 21 min 26 sec ago
Joined: 02/19/2014 - 14:46
Posts: 1455
Location: Alhama de Murcia, Spain
gauss163 wrote:
… Yes. The internal resistance increases immensely as the battery approaches nearly empty. You can get a better understanding of the full impedance spectrum by perusing Nyquist plots (search on those buzzwords to find expositions on this and related topics).

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. LOL

Cheers

Copper is mine, copper divine!

Votes & comments: https://imgflip.com/i/1rwxix 

paul02
Offline
Last seen: 1 week 2 days ago
Joined: 01/29/2016 - 05:01
Posts: 10
Location: Singapore

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.

HKJ
HKJ's picture
Offline
Last seen: 11 hours 59 min ago
Joined: 05/24/2011 - 12:23
Posts: 5204
Location: Copenhagen, Denmark
paul02 wrote:
What would your advice then be for discharging phone batteries to ensure a proper calibration of them?

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.

My website with reviews of many chargers and batteries (More than 1000): http://lygte-info.dk/

Barkuti
Barkuti's picture
Offline
Last seen: 21 min 26 sec ago
Joined: 02/19/2014 - 14:46
Posts: 1455
Location: Alhama de Murcia, Spain
paul02 wrote:
What would your advice then be for discharging phone batteries to ensure a proper calibration of them? …

I’ve not done a (full charge/discharge cycle) “battery calibration” for months on my XT1032, and still it shows me accurate enough charge estimations… Cool
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).

paul02 wrote:
… 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.

Stupid myths and [censored] seem to abound everywhere. Facepalm

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? Facepalm

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

Regards,
Salvador

Copper is mine, copper divine!

Votes & comments: https://imgflip.com/i/1rwxix 

gauss163
Offline
Last seen: 1 hour 36 min ago
Joined: 10/09/2013 - 18:04
Posts: 722
Location: USA
HKJ wrote:
paul02 wrote:
What would your advice then be for discharging phone batteries to ensure a proper calibration of them?

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.

Modern fuel gauges normally do not require a complete discharge to “recalibrate”. This was necessary only for much older/dumber gauges, which you won’t find nowadays (except possibly on very cheap devices).

This was discussed recently in this thread.

gauss163
Offline
Last seen: 1 hour 36 min ago
Joined: 10/09/2013 - 18:04
Posts: 722
Location: USA
Barkuti wrote:
I minimize battery wear by not charging it above 60%,

Did you really mean 60%? Is so, that’s absurdly conservative (and must be quite inconvenient)..

Barkuti
Barkuti's picture
Offline
Last seen: 21 min 26 sec ago
Joined: 02/19/2014 - 14:46
Posts: 1455
Location: Alhama de Murcia, Spain
gauss163 wrote:
… Did you really mean 60%? Is so, that’s absurdly conservative (and must be quite inconvenient)..

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. Steve

Cheers

Copper is mine, copper divine!

Votes & comments: https://imgflip.com/i/1rwxix 

JakeDjanitor
Offline
Last seen: 2 months 1 week ago
Joined: 10/27/2015 - 09:00
Posts: 677
Location: North East USA
Barkuti wrote:
gauss163 wrote:
… Did you really mean 60%? Is so, that’s absurdly conservative (and must be quite inconvenient)..

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. Steve

Cheers

How do you get it to stop charging at a certain percent?
gauss163
Offline
Last seen: 1 hour 36 min ago
Joined: 10/09/2013 - 18:04
Posts: 722
Location: USA
Barkuti wrote:
gauss163 wrote:
… Did you really mean 60%? Is so, that’s absurdly conservative (and must be quite inconvenient)..

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).

The Battery “University” page that you refer to is chock full of nonsense – as are many other pages there. Note that there are no references to scientific literature supporting those vague claims. Nor are the claims made in any precision that they can be scientifically evaluated (e.g. they completely lack essential context, such as cell chemistry, precise test conditions, etc).

That’s one reason why BatteryUniversity.com is blacklisted by Wikipedia. It’s a collection of hearsay and old wives tales assembled by the CEO of a charger company to help promote sales of his chargers. The author has no background in the field.

DBSAR
DBSAR's picture
Offline
Last seen: 3 hours 9 min ago
Joined: 02/11/2013 - 23:28
Posts: 4253
Location: Ontario, Canada

Thanks HJK for the info 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.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

JakeDjanitor
Offline
Last seen: 2 months 1 week ago
Joined: 10/27/2015 - 09:00
Posts: 677
Location: North East USA

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

Barkuti
Barkuti's picture
Offline
Last seen: 21 min 26 sec ago
Joined: 02/19/2014 - 14:46
Posts: 1455
Location: Alhama de Murcia, Spain

gauss163 wrote:

The Battery “University” page that you refer to is chock full of nonsense – as are many other pages there. Note that there are no references to scientific literature supporting those vague claims. Nor are the claims made in any precision that they can be scientifically evaluated (e.g. they completely lack essential context, such as cell chemistry, precise test conditions, etc).

That’s one reason why BatteryUniversity.com is blacklisted by Wikipedia. It’s a collection of hearsay and old wives tales assembled by the CEO of a charger company to help promote sales of his chargers. The author has no background in the field.

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. Hat

Regards,
Salvador

Copper is mine, copper divine!

Votes & comments: https://imgflip.com/i/1rwxix 

ChiggerPepi
ChiggerPepi's picture
Offline
Last seen: 3 days 2 hours ago
Joined: 08/20/2012 - 19:32
Posts: 614
Location: Big Island, Hawaii

Thank you HKJ!

Pages