18650 battery charge time?

[waterface]

How long should i charge my 18650 battery for! mean it's not totally dead, but things were looking a bit weak!
The o-like battery charger, i'm not sure how long it takes!! Should the light change from red to another colour?
Can i leave it on all night without waking up dead due to house fire?
I'm just not sure due to no instructions!

There is something on the side of the box about Digital Cam & Camcorder 3.6/3.7V, 7.2/7.4V & HIGH CAP, each with different times between 2 & 4hrs!!

I hope someone can advise!!

Thanks

Wf

 

[charliebruce]

It shouldn't take more than 6 hours to fully charge from totally dead. If you have a multimeter, try measuring the voltage - 4.2 = fully charged, 3.7 = mid-way. 3.2-3.5 = on the way out, 2.7-3 = about to die (will die if not protected). I've heard of cheap Chinese chargers bursting into flames, if you're worried, power the charger off 12V and not mains - many chargers have this option. Personally, I took my Chinese charger apart and inspected it before using, then kept a close eye on it for the next few uses, until I was confident it would not kill me in my sleep.

 

[Svensson]

I've got a cheap DX charger with a led that turns green when you put the batteries in, then turns orange is soon as you plug the charger in and finally turns green again when the batteries are fully charged. Still not sure if the charger then switches itself off automatically, so it's always safest to unplug it immediately after the green light. Don't know if it's the same with this O-like charger, so to play it safe don't leave the charger on while you're asleep or when you're not around to keep an eye on it.

 

[waterface]

I'm in UK too & am wondering if the one i got is safe!! I haven't a clue how charged the battery is, i just know that my laser is a bit dimmer & the beam seems a bit narrower & less visible since i got the battery on Friday & been using it a lot & now i think it needs some juice, however is not totally dead!!

So its not possible to overcharge the battery?, i will be in house tomorrow & think i'll leave it on charge for about 5 hours keeping an eye on it! Although i'm sure when i put it on charge, the light on charger was red & now is green, but can't say for sure!

Does the laser gradually get dim or just caput when below a certain power & is it best to only recharge when totally dead?

thanks

 

[charliebruce]

Batteries with a protection circuit are essentially "safe" from overcharge and overdischarge, however this doesn't prevent the charger developing a fault and shorting itself. More advanced circuits will also protect against over-current whilst charging or discharging, but I wouldn't rely on this as much. I'd just keep an eye on it whilst charging and use a fused plug. Also, if you suspect the batteries are being charged too fast, a good sign is that they will get hot. Normally, li-ion batteries get pleasantly warm when charging properly, if they're being mis-treated they can get very hot indeed (if too hot to touch, something's wrong).

Generally, you put the battery in, it will go from green to red/amber, and after the current drops due to it/them being fully charged, the light generally turns green, but some chargers may glitch and flick around between orange and green for a bit.

Depending on the driver used, the output power can drop as the battery voltage drops, but when the overdischarge circuit cuts in, the laser will suddenly appear to "die" without warning (freaks people out occasionally, don't worry!). The battery voltage at that point measures 0v and *needs* a charge. Unprotected cells would continue to discharge at this point, and the internal chemistry of the cell starts to change, damaging them permanently.

 

[rpaloalto]

I'm almost certain the battery from O-Like is a unprotected cell, regardless it is always a good idea to never leave these type of cells charging, unattended.
Yes they are prone to leakage, and in some cases a fire hazard.
Your main concern is that lithium-ion cells don't like to be overcharged. As soon as it reaches 4.2 volts you want to stop the charging process. unless your sure your charger or battery has automatic cut off. It might not cause a fire but you will decrease the batteries life severely. Like wise, don't let them drop below 2.V As it most likely will be unable to recharge again.

Charging time will also depend on the mA of your charger. I have one that has a mA of 650, it will charge a 18650 in about 2 hours. I also have a charger rated at 450mA and it usually takes a extra hour or two.

 

[LarryDFW]

rpaloalto is correct.

It should take a couple of hours to charge with a decent charger.

Take it off after that time frame.

Use Japanese cells if you are concerned about about safety.

I would trust them more than a no-name protected cell.

LarryDFW

 

[waterface]

Ok, charger is very basic with just a light at the top & it says 'charger', no brand name or anything.
On the back it says 'Video/Digital Camera Travel Charger'
Input AC 100V-240V 40/60Hz
Output DC 4.2V 600 mAh

I haven't got a meter that can tell me if the battery is full power or not, i just recall my laser not being as bright & not wanting to burn as well, so i thoughta charge was in order!

I noticed i had it on charge last night for around an hour & the light went from red to green! I guess that means its charged!, but today i put it on charge & the light remained red & i hadn't used it since last nights charge.

 

[rpaloalto]

It's normal for a cheap 18650 to loose a little power after removing it from the charger.
If you had a DMM I would bet it dropped down to 4.1v. The charger is looking for 4.2.