Self-Charging Battery?

[CheesyWalnut]

I have a cheap ultrafire 18350 (dont worry i have some nice aw's as well). And it seems to self-charge after I take it out of the charger. When I took it out I measured the voltage was 4.20v but after a few hours without being anywhere near the charger the voltage was at 4.32v! The battery is not getting warm at all and my DMM is new with a fresh battery I also checked my other batteries and they were all at 4.2v. Anyone know whats going on or have the same problem? At least the batteries were only $5

 

[Tmack]

Whatever is happening really doesn't sound safe. Don't be the next guy to mange his hand and get rid of it safely ..

I'm sure someone knows whats happening, but till then, put that thing outside!

 

[CheesyWalnut]

Whatever is happening really doesn't sound safe. Don't be the next guy to mange his hand and get rid of it safely ..

I'm sure someone knows whats happening, but till then, put that thing outside!

I already put it outside and the voltage seems to have stopped at 4.32v I read somewhere that it can't go over 4.40v though

 

[Tmack]

Good move. After seeing what happened to that poor older guys hand, I wouldn't want you sitting the trying to figure out what happened and boom! Good thing you have sense.

 

[Things]

Normal, batteries are based on chemical reactions so won't stop instantly once you stop charging. You'll find the second you use the battery it'll drop back to normal, those extra few millivolts have very little capacity behind them. In fact 80% of a lithium batteries power is between about 4 and 3.3V.

 

[Tmack]

I just notice that very thing. I measured some freshly charged IMR at 4.19. I clicked the laser on for a few seconds to meter it. That little amount of time took them down to 4.13v.

 

[CheesyWalnut]

Normal, batteries are based on chemical reactions so won't stop instantly once you stop charging. You'll find the second you use the battery it'll drop back to normal, those extra few millivolts have very little capacity behind them. In fact 80% of a lithium batteries power is between about 4 and 3.3V.

I tried using it for a while and then charging it back to 4.2v but the battery still started to go over again thats when I put it outside.

EDIT: just a random question does anyone know what voltage i should stop using the batteries and what voltage is the "storage" voltage for storimg long prriods of time?

 

[Things]

Stop using at 3.3V, 3V absolute max, and store between 3.7-4V.

 

[ryansoh3]

Check your DMM cells, if they're almost dead, they tend to give higher voltages than normal. I was baffled by what I was seeing too until I realize the low voltage indicator.

 

[CheesyWalnut]

Check your DMM cells, if they're almost dead, they tend to give higher voltages than normal. I was baffled by what I was seeing too until I realize the low voltage indicator.

I am sure the battery is ok I checked all my other batteries and they were all still at 4.2v

 

[CheeseHasLeafs]

Putting it outside? Was it warm outside when you did that?
Like Things said, batteries run off chemical reactions, and heat accelerates those reactions. That's the reason why batteries don't like the cold, and why, if your phone ever runs so flat you can't recharge it, you leave it in the sun for a few minutes.

 

[CheesyWalnut]

Putting it outside? Was it warm outside when you did that?
Like Things said, batteries run off chemical reactions, and heat accelerates those reactions. That's the reason why batteries don't like the cold, and why, if your phone ever runs so flat you can't recharge it, you leave it in the sun for a few minutes.

it was not hot at all and putting it outside had no effect because it wasnt very cold i live in southern california