Life expectancy of a 18650

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dazed1
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Life expectancy of a 18650

What would be the general conclusion of 18650 shell life?

Lets say you charge them like 50 times per year, would Panas green protected still hold charge/volts good enough and not losing more then lets say 5-10% output or any at all after 2/3 years?

At what poing you guys replace your batteries and how do you notice it? output drop? any hints on how to prolong the life? (just don’t say charge them to 50%) when i use my light on daily basis….

Thanks!

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

Kodachrome40
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Keeping most lithium ion batteries between 40%-80% of charge prolongs their life cycle from around 500 cycles to about 2000 cycles.

Phone, Ipod, Iphone, Laptop, Digital camera batteries are examples of what I use the 40-80% rule for.

I keep my 18650 between 3.8V-4.0V. I don’t let them go lower than 3.8 and stop charging them at 4.0V.

I do have some laptop pulls which I charge to 4.22v every time. I simply don’t much care about performance or battery life on those. But I still won’t take them lower than 3.8V.

Here are some links:
How to Prolong Lithium-based Batteries

Check out table 4: Table 4: Discharge cycles and capacity as a function of charge

My ipod touch is 3.5 years old with a bit more than 1400 charge cycles on it and I still get 85% of runtime of when it was new.

Lets not forget temperature and abuse factors are very important as well.

dazed1
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I dont’ quite get the first part of your post.

“Keeping most lithium ion batteries between 40%-80% of charge prolongs their life cycle from around 500 cycles to about 2000 cycles”

How can i keep them like that? lets say i fully charge my light, and use it for 1/2 minutes to check out my yard. I use 400 lumens mode on my TK 75 most of the times…..so lets say i use it for 2-5 mins every day or once every 2 days. How can i get it do 40%? i mean i don’t get the idea, should i intentional discharge to 40% and then re-charge? what if i use it once per week? its really confusing to me. If you use just a little your flashlight per day, you cant discharge or recharge like that, its way to complicated.

Edit, i guess charging them at 4.0 volts, while having like 80% of the maximum capacity is the best way to do it? its a bit easier to understand that to me now, thanks!

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

Kodachrome40
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Sorry I didn’t explain my reasoning well.

What I meant to say was I won’t let the battery voltage go lower than 3.8V. If it takes you one day to get there or one month it doesn’t matter. Use your flashlight and when battery reaches 3.8v, then charge them.

You can use an inexpensive multimeter to check the voltage. After a few times you’ll get an idea of how fast batteries are going down in voltage and then it gets very easy.

I use this very inexpensive meter to check for voltage. Link

dazed1
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So charge them to 4.0, and dont let discharge to lower then 3.8? isn’t this to little of a difference, and will make me recharge every few days? at what capacity (generally) does high quality cells go to 3.8V?

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

Kodachrome40
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dazed1 wrote:
So charge them to 4.0, and dont let discharge to lower then 3.8? isn’t this to little of a difference, and will make me recharge every few days? at what capacity (generally) does high quality cells go to 3.8V?

Please notice, I only do this to expensive cells I want to keep for a long time. I am sure its not very practical to do for very high powered lights.

3.8v to 4.0v is aprox. 40% of battery capacity. For example on my AW 18650 Protected 3400 mAh, 40% of 3400 is 1400mAh. That’s a little more than 4 hours on low on my light. So its not very inconvenient for charge every 4-5 days or so.

CRX
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The Panasonic 18650 A,B & CH and Sanyo 18650 2600 really rock for longevity & capacity.
That’s why a lot of the top brands have these cells inside.

I started this hobby about two years ago so i’m still a newb but i can’t really notice any decline in my very first panasonic cells, an 18650 A and an 18650 CH which may have been slightly abused due to my ignorance at the time.

The cheaper brands really are not worth buying as far as i am concerned – i must have thrown out five “DubiousFire” cells to every panasonic that i still have.
I have Sanyo 2600’s from laptop pulls that must be five years old at least and are still going strong.

When you use your flashlights frequently you really get to know them and can tell good cells not so much from visual output but from runtime and especially from how hot the light gets in high mode.
I even use this as an indicator of when to recharge batteries, there’s a noticable decline in the heat of the light.

I have ruined a few cells and would say the number 1 causes of destroying a Li-Ion is running it to below about 3v, shorting them out or cutting them in half with a hacksaw. Smile
So best to treat them with respect in those regards.

As to prolonging the life of cells, i keep all my cells near enough fully charged at all times and cycle them at least once a month.

I really don’t see the point in storing them at a third or half capacity or whatever because the whole point of batteries is to use them for convenience or when you need them most, probably when there’s no power for your charger…
Sure it may decrease the overall life of the cells but with so many good batteries coming out and the technology improving constantly you’ll want to be buying and replacing cells every 2, 3 or 4 years anyway.

That’s just my thoughts.

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CRX wrote:
I have ruined a few cells and would say the number 1 causes of destroying a Li-Ion is running it to below about 3v, shorting them out or cutting them in half with a hacksaw. Smile

I always thought it’s best to cut them in half using a blowtorch :bigsmile:

Lights out! That's when things get interesting...

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I was out of gas at the time Smile

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Thanks alot guys, i’m realtivley new to flashlights/chargers/batteries, i got my Panas green protected 3400 mah, (NCR18650B) having use them for around 1 year, so i always wanted to know what is the best way to prolong life, while having the max output – and optimal charge.

i now know the “best” way of doing it.

Charge to around 4-4.10V and don’t discharge lower then lets say 3.7 – 3.8V i think this is the best balance generally, i also keep my TK 75 (with batteries) in room temp not over 25-30c at most. Thanks one more time.

Edit, my incmong Efest LUC V4 (updated version) will be great in order to know when to get them of the charger, ~ 4.10V without having to check the volts, it has voltmeter on the LED screen, making life so much simple!

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

B42
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Check your Efest LUC V4 charge termination with a multimeter too though if that light runs in series. I notice some bays tend to terminate lower than others, 4.12-4.17, very dissappointing since I bought it to charge all evenly to 4.2V when I needed 4 at a time, as an alternative to the TR-008, which only has 3 bays and always charges all bays to 4.14V. Its kind of nice in a way, a charger imposed battery life increaser.

I also have had some Panasonic 3400mAh batteries that I have had for over a year, with heavier use than most I have heard on here, I tend to have 1+ hr/night average, sometimes up to 3hrs of usage of a light/night walking dogs. No difference in capacity that I notice yet. I do have more lights and batteries that I cycle through, so at least a couple hrs/wk usage is what they get. The only cells I’ve had a problem with (other than crappy Ultrafire in the very beginning) is a red Sony I got from someone else, they got very hot on charging, so I tossed them.

dazed1
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Thanks for the tips, but can’t you use the leds on the display to see the volts? or its in-accurate? i plan to remove the batteries from the charger @4.10 +-

What are the downsides of different volts (after termination)? not sure if TK 75 batteries are in parallel or serial tbh.

Also good to here about the panas doing great.

P.S. Do you have the updated version of the LUC V4?

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

CRX
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You could also hook up the volt meter Kodachrome40 linked to a TP4056 charger board to make one of these and have a handy compact charger/volt meter in one.

http://budgetlightforum.com/node/13913

You might find this information from HKJ useful too

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For batteries you using,

Charge them maximum to 4.1V (90% SOC) and keep cool and recharge when resting voltage 3.8V or higher —> maximum life expectancy

charge them 4.2V and use them till empty and keep hot —> lowest life

Cycle life:
if battery has 300 cycles before capacity reduce to 70% its 100% full charge cycles.
that battery may have around 1000 cycles if you discharge 50%

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CRX wrote:
You could also hook up the volt meter Kodachrome40 linked to a TP4056 charger board to make one of these and have a handy compact charger/volt meter in one.

http://budgetlightforum.com/node/13913

You might find this information from HKJ useful too
!{width:98%}[IMG]http://i.imgur.com/GUX9Ggo.jpg[/IMG]!

I’m new to 18650 Li-ions and was wondering how it can have 0% capacity at 3.3 and 3.2. If it has no capacity left at 3.3 how can you still run the cell down to
3.2 and still have light?

BTW that’s a nice chart on capacity TY. I’m keeping a copy for reference.

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I just (dis)charge my cells to 3.8v checked with a DMM and then leave them in their battery boxes.
Mine stay at 3.8v for 6 months+. Not sure how much longer because that’s the longest I’ve ever kept them in storage.

Slewflash 

CRX
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I’m no expert but as far as i understand it, about 3v is the lowest a li-ion cell is happy to go to, any lower and damage occurs so the voltage range for these cells is 2.8-3v to 4.2v

3v= fully depleted and 4.2v= fully charged. 3.7v is the nominal, average or working voltage of the cell.
This was confusing to me at first too.
They will still be able to output some power below 3v but like i said, it’s really bad for their chemistry.
Check out my signature links for more useful charts Wink

ACruceSalus
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Great TY CRX I think I understand. Also two more good links to bookmark.

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ACruceSalus wrote:
I'm new to 18650 Li-ions and was wondering how it can have 0% capacity at 3.3 and 3.2. If it has no capacity left at 3.3 how can you still run the cell down to 3.2 and still have light? BTW that's a nice chart on capacity TY. I'm keeping a copy for reference.

There is a large difference in voltage, depending on when you measure it, when loaded it is significantly lower.

In some cases that difference can be more than a 0.5 volt.

In the chart below I am switching a 3A load on/off. The red line shows the voltage and it jumps up and down with load/no load:

CRX wrote:
I'm no expert but as far as i understand it, about 3v is the lowest a li-ion cell is happy to go to, any lower and damage occurs so the voltage range for these cells is 2.8-3v to 4.2v 3v= fully depleted and 4.2v= fully charged. 3.7v is the nominal, average or working voltage of the cell. This was confusing to me at first too. They will still be able to output some power below 3v but like i said, it's really bad for their chemistry. Check out my signature links for more useful charts ;)

How low a LiIon cell can go depends on the chemistry and if you measure loaded or unloaded voltage. A modern Panasonic cell can usual go down to 2.5 volt when loaded, but will recover to 3.3 volt when the load is removed.

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

dazed1
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Thanks alot guys! its alot clearer now Smile

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

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I think that they should still hold. I have had a good experience with this. I would say a small loss is expected after a couple of years. I love the chart that was placed above. Thanks everyone

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I will toss an 18650 for ANY reason or for NO reason. Sometimes I just get tired of the wrapper colors.

When I get down to ~1 or 2 spares per flashlight, I’ll go scrounge another laptop pack & just dare any of them to so-much as annoy me.

But I charge most or all of mine more than 50 times per YEAR!! The best three or four get charged a couple-three times a week or more.

The newer ones are better than the older ones, so why keep them?

Dim

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I still have some of my first 18650 batteries ...

I find they either work ok or they lose their capacity to hold a charge ( cheaper nastier batteries ) for any length of time . 

Twice a year I go through my rather large 18650 collection to recharge them all , ( Takes about 3 days ) and its this time I check them for voltage ..

The ones that have lost there charge in 6 months just sitting doing nothing get discarded , but the better quality 18650 hardly lose any charge at all . 

I have one panasonic that if left @ 4.2v will still be 4.2v 6 months later .  

And other batteries that will be close to 3v after 6 months .. ( See the trend here ) 

Good batteries will hold a charge , cheap batteries will self discharge , and require more frequent charging ( maintenance ) 

Im also leaning more towards non protected batteries , as cheap protection circuits might put a slight drain on the battery ( I have noticed this ) 

Removing the protection circuit stops the battery from self discharging .  

If I buy more batteries , they will not be protected .  

 

As for degradation ( ageing ) , this is highly variable and depends very much on initial quality and how much the battery is used .

 

 Always remember , the easiest thing in the world to do , is to expel hot air from your lungs and through some vocal chords ..
The resulting sound may , or may not be worth listening too ….

 

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I store all my 18650 fully charged if they Are garbage in 5 years I don’t care because than we will have better and newer cells which I want anyway…

zelee
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some of my first 18650s already give up last week,i got them 2010 and been cycled charger 30-35 times a year.
thank you for your services :_(

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I am kind to everyone, but when someone is unkind to me, weak is not what you are going to remember about me.

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Kodachrome40 wrote:
Keeping most lithium ion batteries between 40%-80% of charge prolongs their life cycle from around 500 cycles to about 2000 cycles.
Lets say your 18650 is 10 Wh (for simplicity)
500 0-100% cycles = 5000 Wh
2000 40-80% cycles = 8000 Wh
It’s not really 4x the lifetime, it’s only 1.6x.. with the addition of major inconvenience.
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Kodachrome is right, 40-80% is the optimum. One cycle are always 100%, no matter if you use 3 times 33.3% or two times 50%.
For example the tesla always charges his battery pack to 80% to enhance his lifetime you need to select the full charge in the cars settings and even than it only lasts for few days until it switches back to 80% max…
But you have to think of the huge amount of cells and the costs in this case, that way different with a dozen cells from a flashlight fan.
—-
I am sure most here recharge the cells before they are empty, I do so, if I recognize a flashlight dimming I recharge this is good for cycle punt and for fun.

Batteries are so cheap so I don’t care so much about this and I always charge them fully because I want maximum current/brightness.

dazed1
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Hmm, it depends what cells you are using. Personally i like high quality batteries which cost like 10$ + per cell, (panas green 3400 protected) and considering i got 2× 4 cell lights, not exactly cheap.

Fenix TK61 MOD> resistor, transistors, copper heatsink, Artic Cooling MX4, dedome, 3A > 5.7A ~ 1700 lumens > (600.000cd)

Werner
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I only have brand batteries but a pair protected panasonics costed me below 14$…so I have bought a dozen or so, I remember times were good batteries were not available or very expensive but it’s a lot better now even ten dollar is okay if you consider to get the best protection circuit and a very good cell…
Sanyo 2600 cost around 11$ per pair…
The lgD1 4.35V batteries are also not so expensive( I ordered 3 pair for 9$ each at fasttech), I recommend them because the higher voltage is a huge benefit especially if you want to use them with linear drivers like the nanjg.
Charging them to only 4.2 gives you the benefit of high cycles with the benefit of high voltage….

I have some lipo RC packs which I store at 3.6V because these are somewhat expensive and I know that I don’t need them fully charged all the time, but even in this case I know that I can toss them in few years…

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hallo.i dont want to open new thread…can you reccomend to me any protected 18650 cells-the cheap ones? i need many of them…trustfire flames?
now i need cheap ones,but protected..

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Kodachrome40 wrote:
Sorry I didn’t explain my reasoning well.

What I meant to say was I won’t let the battery voltage go lower than 3.8V. If it takes you one day to get there or one month it doesn’t matter. Use your flashlight and when battery reaches 3.8v, then charge them.

You can use an inexpensive multimeter to check the voltage. After a few times you’ll get an idea of how fast batteries are going down in voltage and then it gets very easy.

I use this very inexpensive meter to check for voltage. Link

You guys must not walk the dog for an hour every night or go hiking, ect.!!!

When I am done my walk, my lights[K40vn,TK75vn, TK61vn, ect.] are around 3.6/3.7v. If I want to keep them at your suggested 3.8v, I would have to shorten my walk[The Siberian would not like that!] or bring another set of batteries w/ me!

I have had my 3400mAh Orbtronic 17 months now, mostly used on turbo, and they still get 52 minutes of max run time compared to 62 when new. My batteries may last 2/3 years but I will get my moneys worth of enjoying them, which to me is not 5 or 10 minutes at a time! Then again, there are people who do that and theirs will last longer.

I see your point but it does not apply to me.

If people were more like Dogs the world would be a better place. There would be much less conflict and violence,instead there would be true harmony and grace.

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