Failing 18650s

[JimmerG]

Hi all,

I've had problems with a couple of protected trustfire 18650s... having been fully charged, and worked initially - they simply fail.... and read 0.0 on the multimeter. However if I stick them back in the charger for 10secs or so - they go straight back to 4.18v. I can only imagine the protection circuit has 'tripped out' and that a quick blast on the charger resets it.

Could this be right? Are they ready for the bin? - they've probably only been used/charged 10 - 15 times.

Might they have been cheap rubbish? Has anyone else had this problem?

Thanks

J

 

[TooManyGizmos]

Did you always use them until the protection circuit 'tripped out' ...?

If so ... wondering if it could have damaged the protection circuit ?

What was their history of use ? What is their age ... 2/3/or 4 years old ?

Your experience could teach us something .
.

 

[yellow]

trustfire

Might they have been cheap rubbish? Has anyone else had this problem?

yes, rubbish,
as most everything made extremely cheap (and thus downgrading on quality)
... but should still work.

You do not mention the application, could it be thats a hotwire?
Maybe the initial "cold wire" current spike is too high (with a bit of using the bulb)
or is it just when using the multimeter?

 

[45/70]

You do not mention the application, could it be thats a hotwire?
Maybe the initial "cold wire" current spike is too high (with a bit of using the bulb)

It does sound like an over current situation is tripping the protection circuit. As to why that may be, requires more information.

Dave

 

[Kremer]

My guess is they have developed a high internal resistance and under load the voltage sags enough to trip the PCB low voltage cutout.

 

[greenLED]

"Trustfire" is a famous oxymoron. You save nothing buy buying cheap batteries.

 

[Lighthouse one]

THe unprotected cheap batteries work much better- less to go bad. Buy higher quality if you really want to run the protected ones. Don't let them run down if you can help it, but recharge often.