I googled this question thinking I’d see this question asked a thousand times, but I didnt see it at all. I guess what I am asking is, if any of us buy a good quality Panasonic, or comparable quality Li Ion 18650(protected) to be used in flashlights primarily, and it gets charged maybe 4-10 times per year or so, how long can you expect them to last before they get bad and wont hold much of a charge any more?
I bought a few rechargeable`power tools in 2003-2005. I know they arent Li Ion, but they dont say whether they are NiCad or NiMh. They are mostly made by Ridgid and Milwaukee, so they are professional grade tools. Any way, I have owned the 18v Ridgid hammerdrill/driver and circular saw rechargeable combo since 2003, and its gotten a lot of usage over that time. Not every day, but its been used many, many times for many larger jobs. I’ve noticed that it seems to self discharge fairly rapidly now, and when fully charged, its charge doesnt last as long as before on either of the 2 batteries. But they are 9 years old! However, I did just completely rebuild the 2 doors and the door frame on a large shed about a month ago, which included sinking about 100 screws from 1” to 2.5” long, but I didnt have to switch the battery out of the drill the whole time. The saw did need a battery change once.
Can I expect that kind of battery life from a Li Ion 18650 in a flashlight? Maybe more? I wonder if the new Li Ion power tool batteries that replaced the batteries in power tools like mine 6-7 years ago last as long as the older batteries did?
Also, while I’m at it, how long will the NiMh batteries like AA or AAA Eneloops or Tenergy Centura’s last in flashlight use?
I wouldn’t use 18650’s for more than 3 years, after that period they build up quite high internal resistance, and often also lose some fair bit of capacity. $5 every 3 years isn’t that much anyways, is it?
I’d guess 3-5 yrs? I don’t believe they will last as long as NiMh or cad. They also have a shelf life whether used or not I think. Hope this helps as I’m pretty new with Li ion my self. Someone else more knowledgeable will chime in I’m sure.
Reasonable quality batteries generally don’t fall off a cliff, they just gradually degrade every year depending on use and storage. Just buy new ones when the performance is no longer acceptable.
Li-on (few hundred cycles) and nihm (maybe thousand) are less hardy than older nicds, so they won’t last as long, but that’s rarely a problem in flashlights.
Li ion batteries die from number of discharges and age (even if not used).
They last longest if stored at 40-60% charge.
They last longer if kept cool, and die much faster the higher the temperature.
The shallower the discharge before recharging the longer they last, conversely deep discharges reduces life.
Sorry i can’t give you an exact number on age or cycles, as far as i know there is nothing out there that can.
You did well with your power tool batteries. I’m an electrician, and we would put cordless sds drills and screw guns through very heavy use where each battery could get charged upto twice a day. After 6 months we would start seeing problems with some batteries, others maybe 12-18 months.
Thats what I heard about Li Ion vs. NiMh. The NiMh’s shouldnt be “topped off”, instead you should run them mostly down before recharging because they have a limited number of cycles, whereas Li Ions are ok for topping off, and shouldnt be allowed to run down below like 70-80% capacity before recharging(at the most), because they arent limited as much by number of cycles. Its more time with them. But Li Ion shouldnt be charged up to full, then stored for periods of time.
4 or 5 charges it should last 10 years if It’s a Panasonic. I have a Ultrafire 2400 mah cheap I bought in 2003 and charge every 2 to 3 months and works great !
On some Ultrafire cells I have noticed a message showing shelf life of 10 years………
Thats kinda what I was hoping, and kinda what I figured to be true. I have 16 lights now, and 5 run on 18650’s. I also have 4 single CR123 lights. Since I have so many, and I dont use any 1 light much more than the others, except for my Jetbeam BC-10 which always has been my EDC light, they get roughly equal use. I dont have a night job, so the only time I use them is mostly when I go out just to check them out, or hiking, or whatever. Realistically, I will not run the Li Ion batteries down within a few months in any one light(except the BC-10), so I will only be charging these 18650’s about maybe 4-6 times per year. Mostly it will be to top them off.
^That being the case, I would think they would last a fairly long time. I wont keep them at full charge for long periods, and they wont be stored at high temps either. I would be really disappointed if I had to buy new ones every 3 years after that little usage!
Just make sure that fully charge the cell and use the light even if 1 or 2 minutes per month until they get real dim before a new charge. Li ions don’t like to be charged every day just for the hell of it…. And if stored for some time leave them uncharged, this will give them a longer life !
I wouldn’t recommend uncharged, they do slowly self discharge and could stop working or have reduced life if they go down to 0V. 40-60% charge storage is ideal
Sorry, by uncharged I meant not charged at full capacity, but uncharged at the low side 50 to 60. If they drop lower than 10 they can be jumpstarted………
