I’m a noob. I got obsessed quick and bought 4 laptop packs and various lights that came with chargers and crapfire batteries. Of course the first thing I do is charge them all up and see how they do. Now I’ve got like 25-30 charged 18650’s and some helpful person tells me I should store them at 3.5V or so. So right now I’m sitting in my basement with a SRK and 3 SK98’s draining my cells. I’m ok with that……kinda. My question is if I have fully charged 4.17V or so cells in a light all year in a glove-box, or just in my normal temp gun safe without using it, how badly will it hurt the cells? Do I even care since I spent less than $2.00 each for them? I’m talking a mix of older 2010 or so Samsung, Sanyo, and Sony unprotected cells 2200mAh to 2600mAh. How long will they last if I leave them charged? This decharging via flashlight is funny. My wife came downstairs and was like WTF are you doing?
I know some prefer to store theirs at full charge in case they need them in an emergency. Panasonic recommend storing at lower charge for cell longetivity.
Be careful you don’t run down the unprotected cells too much and ruin them. You must monitor them constantly. It is a lot of work, I know! I went thru the same exact thing and ran mine down the same exact way. A couple of times I didn’t keep track and ruined some perfectly good unprotected cells. So, when I did this, I ran them down to about 4V, I found that 3.7V took too long for my patience or attention span. I figured 4 was better than nothing (meant two ways )
The problem with manually discharging unprotected cells is that voltage drops off more rapidly at the lower voltages, and it is easy to miss that cut off and over discharge.
That’s the problem here. If you only have a few cells, enough to fill a couple of lights, you would want to keep them charged up ready to use. Also because you only have a few, you KNOW that they will be used soon. All that changes when you have say, 25-30. There is no way you will be using them all soon, so they will sit fully charged. I too, pigged out on some laptop pulls and found myself in the very same situation as the OP!
I ended up discharging them a little with a SRK, a FF Warrior and a C8. And like the OP, my wife came downstairs and saw what I was doing, but after all these years she knows enough not to ask.
I leave my batteries fully charged, but every 2-3 weeks i discharge and re-charge them all leaving them charged, that way they get worked and not just left to self discharge causing problems later.
Edit, Nearly forgot, i use my “hobby charger” but i also use afew FL’s in pint glasses of cold water to disperse the heat quicker as it runs down which means the FL’s and batt’s don’t overheat badly.
I store them fully charged, and if they get damaged… perfect, an excuse to buy newer gen cells!
I don’t expect them to last forever, neither want I to prematurely destroy them (is this sentence correct?), but I know I will replace them with better new cells before they are actually worn out
I just check them once a month and if they fall below 3.7v I charge them, if they don't, they just sit there.
I would never keep them in a flashlight anywhere, for any length of time.
This is why I never wanted to mess with Li-ion cells. I just keep my NiMHs anywhere I want and they last a long, long time. Now, with Li-ion cells, I need to be concerned about charge state, temperature, length of storage. It's BS.
I just keep them in the garage and if they go bad, then to heck with them. It's such a waste of time spent checking, charging, discharging, etc, instead of doing something productive.
Do you have any nichrome wire handy? You could use some of that to help discharge cells, though you’d have to put it where it won’t burn something (and don’t connect it directly to the cell).
You need to get yourself a usb power bank or something - and use it to discharge them - it will (better) have low voltage cutoff, and you can charge your phone or something with them instead of getting a tan with all those flashlights!
Something like an ENB (2 or 3 cell) or ML-102 (single cell) so you can swap the cells easily as you discharge them. Both of these are under $10, and you will probably end up actually keeping a couple cells in them to actually use.
BTW - got a good laugh - could see my wife saying something similar. LOL
Not only can you not let them fall too low in voltage, but it is not a good idea to let them stay fully charged for a long time with out using them. From what I have read, Li-ions like to be used every day. Fully charged they can loose upwards of 40% capacity per year in hot environments. At 3.7V, only about 4%.
Now that I think about it, that is probably why my GPS batteries have gone bad so often and quickly. I leave my GPS on and plugged in on the windshield. During the summer they get very hot in a fully charged state. Of course once the battery goes kaput it still works so long as it is on the car charger.
A number of years ago, when all I was interested in was getting things done, I really abused the NiMH cells that I had. I used to throw them on a 15 minute charger and thought nothing of it. They used to get really hot while they were charging and I knew it wasn’t good for them. But back then just getting them charged up and put back in use was more important than anything. Trying to optimize and maximize everything one does is just not possible, and you can drive yourself CRAZY trying.
who cares?
i want them ready when i need them.they will get recycled as they fail.
having access to 6 month medical pull packs and transmitting tubes spoils me.
i mess with so much in gadgets that batteries get turned over often.
keep em charged and ready.no fun to be the proud owner of a bunch of fancy lights and a pile of intentionally discharged batteries when that freak storm takes your power out for a few weeks!
Why do you full discharge and recharge them…that over stresses the batteries, in fact, just topping them off before the charge gets too low is a very good way to make them last longer
For Li-Ion, I have a few cells that I keep charged. Like one per flashlight that is in rotation (inside it) and max one or two per type of cell. The rest I keep at around half charge in a cool and dry cellar. I try to rotate as few Li-Ion cells as possible.
For NiMh I more or less do the opposite. I keep all the cells fully charged and try to rotate all of them into use during a year. Especially the non LSD batteries. If possible I use them first and bring Eneloops as spares. Every winter I go over all my NiMh and run a refresh cycle and do a capacity check using my MAHA C9000. For non LSD I may drop them in my MAHA 808M on condition and soft charge once a month or so, if I haven’t used them for a while. And I’ve stopped buying anything but LSD.
I have a bunch of nice 3xAA to D adapters (works fine with either 1, 2 or 3 AA), and I have always tried only buying stuff that use D-cell batteries or AA. Never AAA or C. So I am able to increase the rotation a bit extra on my AA that way.
I also once bought a few 11 Ah non LSD D-cells. They are OK, but I really don’t have any need for them. When I recharge them it is because of the selfdischarge, not because I used up anything even close to the 11 Ah… 3 LSD AA for a total of 6 Ah lasts much longer than a 11 Ah non LSD D-cell. Ah, well. Win some, loose some.
Does anyone have a good suggestion for a good use of 8 x 11 Ah non LSD NiMh D-cells? Too few for a 12 volt application, and I won’t buy any more… :zipper_mouth_face:
I don’t,
I only discharge the ones that don’t get used much in a glass of cold water for 30 minutes to an hour on full with my batterd ultrafire 502b for my 18650s, and my not so used now dereelight c2h with javelin head with my 14500s. That doesn’t stress any parts of the light and batteriers in them at all as they never get hot while discharging, and i have to say sorry, i actualy ment to say 2-3 months Not weeks so that’s my bad.
P.S, batteryuniversitys info is 4 years old and well out of date for new cells.
I decided that in keeping with my ghetto flashlight ways I’ll just keep them charged, check them once a month and if they fall low charge them again. I have 27 good cells from laptop pulls. My only bad cells are the 6 new Trustfire red/black striped 3000mAh that came bundled with flashlights. I figure even with what goes bad I can just pick up another laptop pack to break open once a year. I read on here 18650 cell lifespan is 3-4 years. I think some of my laptop cells are from 2008-2010 and they charge up to 4.17v after resting and last a long time. Someday if the DreamCharger Review: Opus BT-C3100 ("dreamcharger!") is released I may buy one and repent of my battery abusing sins.
I rarely ever use flashlights. I’m thinking this obsession may be winding down. Time to go find something cheaper to obsess over like Meth J) So far I’ve been buying flashlights for 5 weeks. The only thing I want now is a Fandyfire STL-V2. I’ve got these so far:
Here’s my take on this. Quit guessing and wasting your time. Buy an inexpensive hobby charger and be done with it. There are dozens to be had for under $40. I have well over 100 lithium batteries of varying chemistry’s and I can’t even imagine trying to maintain them without my iCharger 3010B. Without a hobby charger or a bunch of really expensive test gear, you will never truly know the status of any of your batteries. Not knowing what is going on is never a good thing and potentially dangerous.
I consider it a tool for batteries, just like a soldering iron for modding drivers and leds.
I don’t worry about the voltage to much. Fully charge them and let’em set until I get ready to use them. If they go bad, good excuse to buy newer better cells, just like someone else posted.
I’m a firm believer that the stored temp’s are more important in cell life than stored voltage. Storing them in a cool place will extend the life of the cell and also reduce the self discharge. In this thread I have had a battery stored fully charged for better than 10 months and it has lost .02v measured a week or two ago from a week after fully charged. The stored temp is around 65°F.
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