18650's Care and Maintenance

[acbezzi]

hello,
i´ve just bouhgt my first 18650 light (fenix TK12 R5), batteries (Trustfire protected) and charger (WF 139).
i have many doubts on the use (charging ,discharging, storing) of this type of battery. i´ve searched in the forum some topic on it but i couldn't find any. i´d appreciate if u guys could help me.:thumbsup:

my doubts are;

1. how should i store my 18650's, charged or discharged?
2. do they have memory effect? i mean, should i completely discharge them before charging again?
3. how long can they keep their energy without being used? i mean, would they be ready for use if i store them charged? or i should charge them just before use?
4. are there any safety reccomendations for charging them, besides not leaving them alone?
5. do they get too hot while charging? should i place a fan or cooler in front of them while charging?
6. are there any hints to prolong their life?
7. my light (fenix tk12) can use either two cr123a or one 18650. what do u think would be the advantages and disadvantages of both?

thax 4 the help

 

[Illum]

1. how should i store my 18650's, charged or discharged?
2. do they have memory effect? i mean, should i completely discharge them before charging again?
3. how long can they keep their energy without being used? i mean, would they be ready for use if i store them charged? or i should charge them just before use?
4. are there any safety reccomendations for charging them, besides not leaving them alone?
5. do they get too hot while charging? should i place a fan or cooler in front of them while charging?
6. are there any hints to prolong their life?
7. my light (fenix tk12) can use either two cr123a or one 18650. what do u think would be the advantages and disadvantages of both?

thax 4 the help

first off, heres some reading to do: Rechargeable Lithium Battery Information - Protected vs. Unprotected Li-Ion Batteries
Read through the basics of Mdocod's MDs Lithium-Ion > Incandescent guide + compatability/comparison chart thread

Enough reading, look at these pictures
Vidpro's "illustrated battery charging concept"
http://www.candlepowerforums.com/vb/showthread.php?t=235745

Vidpro did a good job explaining why cells heat up here, as well as illustrations beginning in post 4
http://www.candlepowerforums.com/vb/showthread.php?t=270416

If you like to see the technical stuff, consult NewBie's Li-Ion protection technology and possible dangers thread

There are battery experts aboard the forum, but I'll just share what I know

btw, :welcome:

It is preferred to have the cells charged for storage. Never attempt to completely discharge cells [~3.8V under load]
I've stored my 17670s for a month without significant drop in charge, but then again I'm storing them in a place where its 77F all year and out of the sun. With basic common sense storage practices you should be fine. I bought rechargeables to eliminate my use of CR123As for nightly excursions, so usually my cells are cycled over and over, barely left in storage for half a month.

Since there are many different types of chargers available, I recommend you to read through Mdocod's Consumer Li-Ion "cradle" charger roundup thread to get a better handle on what charger to buy as well as the characteristics of your charger.

Like all batteries, once its capacity is saturated it will begin to convert the additional energy into heat. If your batteries [I'm assuming unprotected] are heating up during charging. It is likely to originate from two possibilities:
the first is your charger is unable to terminate charge accurately. The other is that the charger only has a single channel, but you are charging two cells in parallel and the cells have a different state of charge between each other. This causes one cell to be overcharged and the other undercharged.

I would prefer to have protected cells in my collection because they protect from overcharge and overdischarge by disconnecting the battery

Note that due to internal resistance any battery chemistry will heat up slightly during charge [as well as discharge], this is normal. It should be warm to the touch and not "hot"

Prolonging their life requires some understanding of battery conditioning, and honestly I'm not doing a good job on mine:shrug:

its debatable on advantages and disadvantages of rechargeables because it involves a couple variables to which you as a user can apply.
If the driver of your light is capable of either, the 18650 is a batter choice, but keep in mind that 2xCR123A has a overall dimension of twice the length of a cr123A, ANSI dimensions as "16340" or 16mm wide, 34mm long, cylindrical. 2xCR123A is then comparable in width to a 16mm wide and approx 68mm long cell. Its closest alternative is actually the 17670 cell. 18650 is the same length but 2mm wider, so normally on lights designed for cr123as 18650s would not fit.

if you use your light only sporadically, rechargeables are not a good investment, especially considering the additional costs of charger and stress .
However, if you use your flashlight every night, rechargeables are the better option because it saves the cost of replacement cells.

There an abundant amount of information on the forum for Li-ions simply because there are so many users here who uses them

 

[LuxLoverr]

great topic! thanks to both

 

[march.brown]

if you use your light only sporadically, rechargeables are not a good investment, especially considering the additional costs of charger and stress.

I would agree with this when using (for example) AA and AAA cells ... My iTP A2s and A3s are used a lot so I always use Eneloops or Hybrios in them ... I also use a few Lithium Primaries AA & AAA (plus spares) in a couple of other torches kept only for emergencies , like in the car.

Unfortunately there is no really compact primary cell to replace my 18650s , so I have to use the Li-Ion rechargeables ... I don't use the three torches (with 18650s) for long periods and I don't recharge them very often ... I probably charge a 18650 every three weeks or so and sometimes even this is before they are fully discharged ... I like the 18650s because I can leave them for months and (if unused) they still measure almost 4.2 volts ... I only check the voltage every three weeks or so ... I realise that it is better to store Li-Ions only partly charged , but I ignore this and keep them fully charged ... My Li-Ions will die of old age rather than due to charging too many times , but I will just replace them every three or four years ... I use Ultrafires so it isn't expensive to replace them.

If anyone is considering using Li-Ion cells , I would suggest that a Digital Voltmeter is bought as this is the only way to tell how much charge is left in the battery ... There are several good threads on CPF about charging and care of Li-Ions and it is essential to read these carefully before embarking on using the Li-Ion cell.

As for the 123 size battery , I would stick to primaries where possible and (preferably) single cell torches ... There again , that is only my opinion.
.

 

[acbezzi]

thank u a lot illum!!!:thumbsup: your post was really helpfull!! my light can hold up two cr123a or one 18650. i have already bought some batteries( two TrustFire Protected 18650 3.7V 2400mAh and two TrustFire Primary CR123A) and a charger (Ultrafire WF139). i´m thinking about using primarily the rechargeable 18650 and leaving the cr123a's in my bag as emergency batteries. comparing one 18650 with two cr123a, which do u think would give more power(light) / runtime?

 

[acbezzi]

thank u mark brawn!

 

[Illum]

march.brown, there is some logic to storing cells at a partially charged state...and I think either mdocod or LuxLuthor gave a percentage of the state of charge for long term storage.
You are hopping along in the right direction. Until I can find that value in a post I'm holding off lest to lead anyone in the wrong direction

DM51 once noted in this thread http://www.candlepowerforums.com/vb/showthread.php?t=274781

Best storage for Li-Ion cells:
· 3.9V
· Between 3°C-10°C
· Dry conditions.

Never store Li-Ion cells:
· Below 3.6V or above 4.1V
· Below 0°C or above 30°C
· Humid or wet atmosphere

EDIT: I forgot to mention this great website called battery university, its an added reference to what we on the forum may have missed during our time explaining
How to prolong lithium-based batteries

yep, apparently the magic number is 40

If possible, store the battery in a cool place at about a 40% state-of-charge. Some reserve charge is needed to keep the battery and its protection circuit operational during prolonged storage. Avoid keeping the battery at full charge and high temperature. This is the case when placing a cell phone or spare battery in a hot car.

acbezzi, thats where certain members of the forum shines, user Selfbuilt reviewed the TK12 sometime in May and posted a review on it. Like many of his earlier [and later] contributions, it will just about answer all the questions the ower would want to know about the light: output, runtime, ergonomics, etc :twothumbs

to answer your question, referring to Selfbuilt's graphs under the assumption that your TK12 was the same as his
AW protected 18650:
Max 2hr 15min to 50% output
High 7hr 18min to 50% output
Medium 15hr 27min to 50% output

2xCR123A
Max 1hr 54min to 50% output
High 5hr 49min to 50% output

Interestingly as it seems the onboard regulator is designed for 18650s, and the 2xCR123A option is added to which the driver overhead allows.

Its always a good idea to keep some CR123As on you, on occasion I would find the need to use my cr123as in lights I brought without spares. In case you're wondering how to go about carrying cells, I'd recommend doing a little hunting around and be a little creative
Battery Holders --Also "Utility Bag" suggestions
How to carry batteries with you
CR123A carriers?
How do you carry spare batteries

Personally I found it easier just to carry another light, chances are where you'll need a light you wouldn't be able to see your own hands in front of your face, thats not the best time to lose a tailcap or load cells backwards. I still own carriers though, mostly for bail-out bags and field provisions. While a little expensive, surefires SC1, SC2, SC3 are good battery carriers, very sturdy little guys that holds 4-6cells in pairs, even comes with a o-ring where the threads meet. Only issue for the SC1 is once awhile theres the risk that there will be a crazy TSA agent/border patrol/military nut living next door thinking you're carrying a VS50...which in design it does resemble the VS50, or a plastic shelled anti-personnel mine. So my SC1 mostly stays at home


Cheers

 

[march.brown]

march.brown, there is some logic to storing cells at a partially charged state...and I think either mdocod or LuxLuthor gave a percentage of the state of charge for long term storage.
You are hopping along in the right direction. Until I can find that value in a post I'm holding off lest to lead anyone in the wrong direction

Hi Illum , I realise that storing Li-Ions in a partially charged condition will give them a longer life , but I'm not worried about gaining a few extra months of cell-life ... I prefer to have all my batteries in a ready-to-use state rather than have to put them on charge before using them ... Personal preference really ... All my LSD AA and AAA cells plus my 18650s are ready to use , even though I don't change them very often.

I check the voltages of the spare Li-Ions every few weeks and today they are either 4.15 or 4.16 volts ... There is one at 4.11 and another at 3.83 but they haven't been charged for quite a few months ... Those two are Ultrafire unprotected (blue) and all the others are Ultrafire protected (grey) ... I don't buy expensive Li-Ions as I will just simply buy more cheapies when these eventually die ... As I said before , this is personal preference and I'm happy with my cell choices so far ... Time will tell.

I also use cheapie protected 18500 Li-Ions in my converted Maglite 2C.

In the 123 size torches , I only use primary cells.
.

 

[Black Rose]

if you use your light only sporadically, rechargeables are not a good investment, especially considering the additional costs of charger and stress .

When I got my Li-Ion cells I thought that I would get a lot of use out of them, but it turns out that is not the case.

I am now at a point where I wonder if I should have even invested in the Li-Ion cells.
I already sold off my 16340 cells as they were not getting any use.
My 17670 cells get no use because the drivers in the drop-ins in my 6P and G2L won't stay in regulation with a single Li-Ion cell, so those lights now have 2xCR123A primary cells in them.

I like having my lights loaded and ready to go, but I have many lights and it seems that I end up using my AA and AAA lights more than my larger lights most of the time.

With hindsight being 20/20, what I probably should have done was buy a pair of 18650 cells and put the cells in the light that I want to use at the time I want to use it, instead of having a cell for each of the lights.

With low voltage drop-ins, better boost circuits, and low vF emitters now available, my need for Li-Ion cells seems to be slowly going away.

 

[march.brown]

With hindsight being 20/20, what I probably should have done was buy a pair of 18650 cells and put the cells in the light that I want to use at the time I want to use it, instead of having a cell for each of the lights.

I keep my spare 18650s in torches rather than in plastic boxes ... The torches can even be used if necessary.

My main 18650 torches are Solarforce L2's and L2i's , so I can use any one of them ... Unfortunately , I still have some 18650s in plastic storage boxes , though I have just sent for another L2i for $12-56 including postage ... I realise that this is more expensive than a plastic storage box , but it looks better.
.

 

[mdocod]

Hi Illum,

Keep in mind that the 3V rating on a CR123 cell is different from the 3.7V rating of a li-ion cell. The trend in the industry tends to be that rechargeable cell voltage ratings are closer to their nominal loaded average voltage, while primary cells are often rated closer to their open circuit voltage. In other words.... Getting 4.2WH (8.4WH for a pair) from a CR123 is pretty rare, but getting 9+WH from an 18650 is quite possible.

Eric

 

[etc]

that's a good point, I hear CR123A is more like 2.8V under load?

 

[qandeel]

Good topic.

Thanks to all the contributers. We keep learning everyday.

 

[Monocrom]

Good topic.

+1

Deserves to be a sticky.

 

[Illum]

When I got my Li-Ion cells I thought that I would get a lot of use out of them, but it turns out that is not the case.

I know the feeling, but I started out exploring then just stuck to running 17670s in Surefires, not so much for the regulation but for the benefit of whipping out a light that shined as if used with new cells week after week. Gradually I sold/given away the LiCoO2s I didn't use [10440s, 14500s, 18500s] and stuck with cycling two 17670s in Surefire L4s. Several years after I bought my protected 17670 it will still hold a charge, but the runtime is very poor...so I decided to retire them. One of which I have removed the protection PCB, soldered some wires to it, and now became a charging dock for unprotected cells

Its not pretty, but in a single channel DSD featuring a lousy termination point some added protection is always welcome

Hi Illum,

Keep in mind that the 3V rating on a CR123 cell is different from the 3.7V rating of a li-ion cell. The trend in the industry tends to be that rechargeable cell voltage ratings are closer to their nominal loaded average voltage, while primary cells are often rated closer to their open circuit voltage. In other words.... Getting 4.2WH (8.4WH for a pair) from a CR123 is pretty rare, but getting 9+WH from an 18650 is quite possible.

Eric

let me go and edit that

+1

Deserves to be a sticky.

Anything Mdocod sets his foot in has that feeling

 

[mdocod]

that's a good point, I hear CR123A is more like 2.8V under load?

Can be as low as 1.8V under a load if you are SureFire many years ago making a "special" bulb for an M4 that only runs a few minutes

Typically, voltage can vary from ~2.2-2.8V on average depending on the load. A 1C discharge rate (1 hour tun) will result in an average voltage ~2.5V through the discharge.

------

Rule of thumb is that li-ion will pull ahead of CR123s under more intense loads, while CR123s will have more energy available when discharged very slowly.


Eric

 

[Mikellen]

I also just started using rechargeable batteries specifically an 18650 protected battery from AW. I do have a volt meter and check the voltage regularly but can someone please let me know at what voltage should I not let the battery drop down to before charging?

Thanks.

 

[Illum]

Aw protected cells only protect against severe overdischarge and usually will not kick in even when cells have already entered into a deep cycled state. Its designed to kick in to prevent a fire or an otherwise hazardous situation, its not meant for the normal operation ofcells. Likewise so are overcharge protection, only some of the nutcases here [like me] depends on it for normal operation. My take for whats "need recharging" is about 3.9V...

I'm not sure where this came from but I have it taped beside my charger and have been using it for years to manually estimate remaining cell capacity. The capacity of cells to voltage is stated as follows:

Capacity   OCV    Load = 550ma
100%      4.20V    4.20V
90%       4.06V    3.97V
80%       3.98V    3.87V
70%       3.92V    3.79V
60%       3.87V    3.73V
50%       3.82V    3.68V
40%       3.79V    3.65V
30%       3.77V    3.62V
20%       3.74V    3.58V
10%       3.68V    3.51V
5%        3.45V    3.42V
0%        3.00V    3.00V

This chart is only meant for rough estimation only, as DM51's numbers will quickly become apparent following this thread li-ion discharge limit - 2.5v/2.7v/2.8v/3v???

 

[pae77]

I also just started using rechargeable batteries specifically an 18650 protected battery from AW. I do have a volt meter and check the voltage regularly but can someone please let me know at what voltage should I not let the battery drop down to before charging?

Thanks.

Most people seem to say ~3.8 volts is a good point at which to recharge Li-ion cells. At 3.8 volts there is approximately 30-40% remaining power in the cell so that gives you some margin of safety. There is no harm in topping up Li-ion batteries that are partially discharged but there is harm in discharging them too low. I would try to avoid ever discharging them below 3.6 volts at which point they are effectively empty.

 

[Mikellen]

Thanks for the information. It is extremely important to know!