Running 18650 batteries flat?

[JohnGalway]

Hello,

Strange question. My friend has had two chargers that both died on him. I have loaned him my 18650 charger, it works. He was going to "try something" ( I don't know what) before buying a new charger that involved "draining his battery".

I presume he means running it down flat.

Will this damage his battery? Is it safe?

Many thanks,

John

 

[HKJ]

Hello,

Strange question. My friend has had two chargers that both died on him. I have loaned him my 18650 charger, it works. He was going to "try something" ( I don't know what) before buying a new charger that involved "draining his battery".

I presume he means running it down flat.

Will this damage his battery? Is it safe?

Running a LiIon battery really empty will damage the battery and make it unsafe.

Running a protected battery, in a high power light, until the protection kicks in, will not damage the battery.
Using a very low mode, to run the protected battery dry, might damage it.

 

[JohnGalway]

Thanks for that, I will let him know. For some reason he's very keen on running down batteries, I guess I am the opposite.

 

[vpr5703]

it wont harm the battery, but given that Lithium Ion does have a limited number of cycles per battery, the lower you run them before recharging the shorter the overall lifetime of the battery is. I don't think it makes a huge difference, but it does shorten its life anyhow.

 

[AnAppleSnail]

He's probably thinking of early NiCds which could benefit from that treatment, supposedly.

 

[vpr5703]

I read somewhere that normal consumers would have to try REALLY hard to get the memory effect to show itself badly enough to be noticed. I know on my NiCd batteries, most are still kicking right along happily.

 

[Bwolcott]

it wont harm the battery, but given that Lithium Ion does have a limited number of cycles per battery, the lower you run them before recharging the shorter the overall lifetime of the battery is. I don't think it makes a huge difference, but it does shorten its life anyhow.

running lithium ion flat will damage the battery, not sure what you are talking about?

 

[vpr5703]

Not completely flat as in 0V, but running them until you hit PCB Cutoff. That won't immediately damage the battery, but will lead to a shorter overall lifespan.

 

[Bwolcott]

Not completely flat as in 0V, but running them until you hit PCB Cutoff. That won't immediately damage the battery, but will lead to a shorter overall lifespan.

oh ok I thought you were saying flat lol

 

[vpr5703]

Nope. I know what that can do, it has the possibility of not being fun at all.