18650 battery charging

[CreeKid1999]

i was wondering if a protected 18650 can be charged safely if it is connected to a 4v ac adapter brick thing that plugs into a wall socket without any further circuitry
cheers :)

 

[Curious_character]

Safely, maybe, depending on how reliable the protective circuit is. But the protective circuit at best will prevent explosion but won't necessary protect the battery against over discharge or pretty gross overcharge. If your adapter produces much above 4.2 volts, the battery will probably get badly overcharged before the protective circuit kicks in. If it produces much less than 4.2 volts, the battery won't get fully charged. Even a slight voltage deficiency will result in a major reduction. It's a bad idea.

c_c

 

[RetroTechie]

The Constant Current part of the charge curve could be like short circuiting that adapter. The end voltage would be controlled less accurate, and without a cutoff point (saturation charge). And this without battery voltage monitoring of any kind. :mad: (for example hooking up with polarity reversed, would almost guarantee vent-with-flame / explosion).

Might work fine. But I'd file under "life-or-death emergency option". Only to be tried on a fire-proof surface. 18650 Li-ions pack too much power to be handled this careless.

 

[gearhead1972]

I have found wall wart adapters to output much more voltage than their spec. I have seen 12v ones put out as much as 18-19 volts...so a 4 volt could be putting out 6.. I wouldn't trust it. Nitcore I4 is like $25, buy it and remove doubt.

 

[wncranger]

I agree. Go with a NiteCore charger or similar. The cost is minimal in comparison to the result of catastrophic failure.

At the very least, your charger could overcharge the battery which decreases its life. At worst, the battery could fail catastrophically. Personally, I've also began researching LiPo protection bags as a further means of protection.

The only way I would use your charger is in an emergency, outside away from flammable objects. Otherwise, it is just too risky, in my opinion.

 

[RI Chevy]

i was wondering if a protected 18650 can be charged safely if it is connected to a 4v ac adapter brick thing that plugs into a wall socket without any further circuitry
cheers :)

Welcome to the Forum! :welcome:

Get yourself a good Lithium Ion charger and put your worries aside. Don't fool around with cheap chargers. Your batteries will also like you more. ;)

Go to batteryuniversity.com and read up more on Li Ion cells.

Read up on both batteries and chargers here. http://lygte-info.dk/