18650's an idiots guide?

[lurcher]

I have recently purchased a couple of 18650 trustfire protected batteries and cheap trustfire charger.

I know nothing about lithium ion batteries. Searching on here I have learned a bit but I have some questions.

1. If I leave an 18650 fully charged but don't use it for any length of time should I discharge/recharge it periodically? or put it the charger for a while every few weeks? what maintenence regimen should I follow?

2. I am guessing it is best to recharge the battery as soon as I notice a drop in intensity in my light (A DBS dereelight) rather than run it flat? Do 18650's go down hill fast if run flat? how bad is it for them?

3. I don't fully understand the dangers of these things. My basic understanding is that if they are overcharged or thrashed in equipment then if things turn to custard they can explode and release very toxic gases. What safety precautions are recommended for these batteries? what causes them to explode.

4. If using a cheap charger are there any guidelines I can follow, setting a timer on my watch to remind me to turn off the charger after a certain number of hours for instance as a safe guard.

Anyhow looking forward to hearing any tips for an idiot regarding maintaining these batteries

Thanks in advance

 

[Kestrel]

Others know more, this is a good start if you haven't read it yet:
http://www.candlepowerforums.com/vb/showthread.php?t=201375
Good job going single-cell, imo. Do a runtime test, then store your extra cell at 80% usage if you'll be needing it, 50% usage if you won't be.

Important: Don't charge your cells if you're out of the house. I have read that people prefer burnt carpet rather than a burnt-down house. :-/

 

[etc]

The reason AW sells "protected" sells is so that the cut off at a certain Voltage, to prevent overdischarge.

that's one issue, the other is overcharging them. Get the Pila charger.

Myself, I don' thave any of them, I am waiting for high-capacity 18650 cells, at least 2500 mAh. (Current seems to be 2200mAh)

 

[SilverFox]

Hello Lurcher,

Maintenance on Li-Ion cells is pretty straightforward.

If the cell is going to be stored for an extended period of time (i.e. longer than a week), you may get longer life from the cell if it is stored at a lower voltage, like 3.8 - 3.9 volts. Every 6 months check the cells voltage. When it drops below 3.4 volts, charge it back up.

You will get longer life if you only use about 80% of the cells capacity, then recharge. To determine the capacity of the cell you will have to run a test. For example, if your light run 60 minutes and then starts dimming, limiting the discharge to 48 minutes would give you longer life than using it all the way until the light dims.

Most of the dangers involved with this chemistry occur during charging. If you are using a high quality charger that follows the proper Li-Ion charging algorithm, you will minimize most of your risks. However, you should always attend to charging and set up your charging area to be "tolerent" of a malfunction during charging.

The best advice I can give you concerning using a "cheap" Li-Ion charger is to put $10 into a jar every time you use it. You will soon have enough money set aside to purchase a quality charger...

Tom

 

[yellow]

as has been said:
* "protected" cells and nothing else
* when not in current use, use them a little bit, then store
* ONE use below a (very small) "safe" Voltage level of 2.5 V and the cell is damaged considerably, without hope to get to full capacity - but better end at 3 Volts
* no matter if used or not, after about 5 years, they start to degrade (most difference to NI-Cd, Ni-Mh that degrade while being used, not while being not used and stored)

 

[brighterisbetter]

Hello Lurcher,

Maintenance on Li-Ion cells is pretty straightforward.

If the cell is going to be stored for an extended period of time (i.e. longer than a week), you may get longer life from the cell if it is stored at a lower voltage, like 3.8 - 3.9 volts. Every 6 months check the cells voltage. When it drops below 3.4 volts, charge it back up.

+1

A very helpful older post from SilverFox is in my sigline, here.

 

[VidPro]

I have recently purchased a couple of 18650 trustfire protected batteries and cheap trustfire charger.

one more point, dont let the life or stability or capability of cells like those , determine for you how other cells would act.
that is all i am saying, is if you feel that li-ion sucks after dealing with it, then try other qualities of cells besides them.

i am not saying anything bad about them, just that if you dont get good life or capacity from them, dont blame the whole chemistry.

 

[LukeA]

The Idiot's Guide To Lithium-Ion Cells:

Use Eneloops.

 

[Kestrel]

The Idiot's Guide To Lithium-Ion Cells:

Use Eneloops.

 

[roymail]

The Idiot's Guide To Lithium-Ion Cells:
Use Eneloops.

Luke... :nana: ... that's a good one!

 

[linterno]

If you have no experience with Li-Ion cells then you have to read a lot about its use and safety. You must do a google search on "li-ion correct usage".

Don't believe that you have to use another chemistry. "If you have never owned a car but a horse then you can learn to drive".

Your batteries and charger aren't probably the best but work. Just be careful like you would be with any better brand.

I will not trust the charger. It will probably over charge your batteries (even below the protection circuit voltage the batteries can be over charged). You better test the battery voltage from time to time using a multimeter. If the voltage is over 4.2 +/- 0.05 (what most manufacturers recommend) then stop the charging.