Recharging Older 18650 Batteries

Church · Apr 15, 2019

Hello, I'm new to the forum and I have a question about recharging batteries. Photo below. I have been recharging several Surefire 18650 batteries that I've had for over 10 years. These were given to me along with several inexpensive Cree flashlights by a coworker several years ago. He also gave me two or three cheap chargers, all of which, I believe, came from ebay at that time. I've had fairly decent luck with these batteries, but there are a few that will not charge and I'm wondering if these have exceeded their lifespan. Several of these batteries have sat unused for a few years, and those are the batteries that will not charge.

I'm wondering if I should think about buying some new brand-name replacement batteries for my lights and headlamps.

Also, is there a rule for specific charge times with these older, cheap, chargers? The way they've always worked for me is that I put depleted batteries in the charger and plug it in and the red light comes on solid, then changes to green once the charge is completed. This can happen in a couple of hours or a few hours. With these batts that have been sitting for so long the light flashes between green and red continuously until the charge is complete, the stays green once the charge is complete. This can take several hours. Some batts don't even get that far, and the charger never turns green. How long is TOO long for recharging an 18650?

Thanks,
Cliff

BB · Apr 15, 2019

A good place is identifying what kind of battery(ies) you have (different battery chemistries have different charging voltages). Identify if these are "protected" vs "raw" cells (protected cells are supposed to turn off the battery if over/under charged... And the charger needs to reset the protection circuit to turn the battery "on" again).

And a good DMM meter (known good meter, good battery in meter). that can read X.XX volts (at least). You want to see what the batteries start charging at, and what they end charging at. Generally, they will charge to ~3.70 volts (LiFePO4) or 4.20 volts (other chemistries). Generally, once the voltage setpoint has been reached, the charger should turn off (no float, absorb charging).

If these were 2,000 mAH batteries (2.0 AH) and that was a 0.50 amp charger, then it would take ~4 hours to recharge from dead.

10 years for your batteries--Probably a good life (given that you don't know how they were treated).

-Bill

hiuintahs · Apr 16, 2019

Ya, it's hard to know what is going on without a voltmeter. Likely the voltage has dropped to a level that your charger doesn't recognize and won't go into a normal charge cycle. If they have a protection circuit on the batteries like BB mentioned, and if it's tripped, the voltage could read 0 volts. Then the battery needs to be reset before your charger will work with it. A couple of things that need to be investigated with a voltmeter before drawing a conclusion. Most likely due to their age, I'd probably just scrap them and get some new batteries. Also I'd get a better charger. Chargers have really come a long ways in the last 10 years. Look at a MiBoxer C4-Upgrade. The display on that charger will give you quite a bit of information. New batteries and a new charger and you'll be buying more flashlights to go along with it!

I recently repaired a battery pack for a neighbor and one of the 18650 cells just would not go past 3.85 volts. I have some nice lithium ion chargers, but in this case, the cell wasn't such that I could just put it into the charger's cradle, so I used an Agilent power supply set with a current limit of 0.500 amps and a voltage of 4.20v. The pwr supply has the ability to do CC/CV (constant current, constant voltage) like a charger. First, I discharged the cell to 2.80 volts and when charging all was going well until it hit around 3.85v. Then the cell just got warm without raising in voltage anymore regardless of how long I let it charge. Something definitely wrong with that cell.

Church · Apr 16, 2019

hiuintahs said:
Ya, it's hard to know what is going on without a voltmeter. Likely the voltage has dropped to a level that your charger doesn't recognize and won't go into a normal charge cycle. If they have a protection circuit on the batteries like BB mentioned, and if it's tripped, the voltage could read 0 volts. Then the battery needs to be reset before your charger will work with it. A couple of things that need to be investigated with a voltmeter before drawing a conclusion. Most likely due to their age, I'd probably just scrap them and get some new batteries. Also I'd get a better charger. Chargers have really come a long ways in the last 10 years. Look at a MiBoxer C4-Upgrade. The display on that charger will give you quite a bit of information. New batteries and a new charger and you'll be buying more flashlights to go along with it!

I recently repaired a battery pack for a neighbor and one of the 18650 cells just would not go past 3.85 volts. I have some nice lithium ion chargers, but in this case, the cell wasn't such that I could just put it into the charger's cradle, so I used an Agilent power supply set with a current limit of 0.500 amps and a voltage of 4.20v. The pwr supply has the ability to do CC/CV (constant current, constant voltage) like a charger. First, I discharged the cell to 2.80 volts and when charging all was going well until it hit around 3.85v. Then the cell just got warm without raising in voltage anymore regardless of how long I let it charge. Something definitely wrong with that cell.

Thank you both for your very detailed help. I could not have asked for better comments. I'll need to find a good charger and figure this out. Oh by the way, I think maybe I figured out how to upload the photos. And I was wrong, these are Ultrafire batteries, but Surefire. Here are the photos:

hiuintahs · Apr 17, 2019

When you said Surefire 18650 batteries, I was a little puzzled as I didn't think Surefire made 18650's. Anyhow, UltraFire, TrustFire, ****Fire, etc are a play on the well known Surefire name. I'd be a little leery of those batteries. For one, there is no such thing as a 5000mAh battery. Highest capacity in a 18650 that I know of is 3500/3600mAh. If needing more batteries, there are a lot of good choices with Panasonic, Samsung, LG or Sony. The Panasonic NCR18650GA is one of my favorites.

This review of the UltraFire 5000mAh 18650 battery by forum member HKJ might be of interest to you. He says they tested out at a little over 1000mAh. I for sure would just scrap the ones that aren't working well for you and not even bother with troubleshooting.

https://lygte-info.dk/review/batteries2012/UltraFire TR18650 5000mAh (Blue) UK.html

Church · Apr 22, 2019

Thanks again, for your help.

Qship1996 · Apr 22, 2019

Surefire does indeed make a great 18650 battery, and it even has a built in usb port to allow charging from any usb power source. At only $16 it is a high quality option available directly on their website.3500 ma also.

WalkIntoTheLight · Apr 23, 2019

Qship1996 said:
Surefire does indeed make a great 18650 battery, and it even has a built in usb port to allow charging from any usb power source. At only $16 it is a high quality option available directly on their website.3500 ma also.

3500mAh, plus a built-in USB port, all within the 18650 size? I'm doubting that. It must be quite a bit longer than 65mm, or quite a bit less capacity than 3500mAh.

Qship1996 · Apr 23, 2019

I have 4 of them,works as advertised and powers my Fury DFT {a light known to be very,very picky about which 18650 you try as it consumes high Amps} for the advertised runtime of the light, so your doubts are unfounded.Klarus and Fenix market essentially the exact same battery, however both charge a significantly higher price for theirs.

check it out yourself https://www.surefire.com/batteries/sf18650b-micro-usb-rechargeable-lithium-ion-battery.html

WalkIntoTheLight · Apr 23, 2019

Qship1996 said:
I have 4 of them,works as advertised and powers my Fury DFT {a light known to be very,very picky about which 18650 you try as it consumes high Amps} for the advertised runtime of the light, so your doubts are unfounded.Klarus and Fenix market essentially the exact same battery, however both charge a significantly higher price for theirs.

check it out yourself https://www.surefire.com/batteries/sf18650b-micro-usb-rechargeable-lithium-ion-battery.html

Are there any independent capacity tests you can link to? That Surefire link doesn't even list the cell's dimensions. It's useless. I still doubt either the 3500mAh claim, or that it really is a 18650 size, or both.

HKJ · Apr 24, 2019

WalkIntoTheLight said:
3500mAh, plus a built-in USB port, all within the 18650 size? I'm doubting that. It must be quite a bit longer than 65mm, or quite a bit less capacity than 3500mAh.

The USB charger is about 5.5mm in length, making the final battery around 70.5mm, that was at least the case for the two I tested:
https://lygte-info.dk/info/BatteryDisassembly18650usb UK.html

WalkIntoTheLight · Apr 24, 2019

HKJ said:
The USB charger is about 5.5mm in length, making the final battery around 70.5mm, that was at least the case for the two I tested:
https://lygte-info.dk/info/BatteryDisassembly18650usb UK.html

Okay, that makes sense, thanks.

Recharging Older 18650 Batteries

Church

Newly Enlightened

BB

Flashlight Enthusiast

hiuintahs

Flashlight Enthusiast

Church

Newly Enlightened

hiuintahs

Flashlight Enthusiast

Church

Newly Enlightened

Qship1996

Enlightened

WalkIntoTheLight

Flashlight Enthusiast

Qship1996

Enlightened

WalkIntoTheLight

Flashlight Enthusiast

HKJ

Flashaholic

WalkIntoTheLight

Flashlight Enthusiast

Similar threads

Latest posts