DC charging circuit question (Vs=12v charging 18650 batteries in series (7.4v total)

H

hoghunter

Member

• Jul 5, 2017

• #1

I want to plug a 12v DC charger into a jack on my device to charge (2) 18650 batteries in series (7.4v). Will this safely charge the batteries 'as is' or will I need a voltage dividing circuit to lower the Vs down from 12v. If I do need a voltage divider circuit, what voltage should I be bringing the 12v (Vs) down to?
Thanks for any help and guidance.

 

MikeMl

Well-Known Member

Most Helpful Member

• Jul 5, 2017

• #2

Stop, read, learn, about the special requirements for charging Lion batteries... ( You have a lot of reading to do)

 

P

Pommie

Well-Known Member

Most Helpful Member

• Jul 5, 2017

• #3

Improperly charging Li-ion batteries will result in fire and maybe an impressive firework display. Don't do it.

Mike.

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Jul 5, 2017

• #4

There are numerous charging modules available for them, use them!!.

 

H

hoghunter

Member

• Jul 5, 2017

• #5

Wow!! Glad I asked. Thank you so much for the heads up! I will do some research and look online for charging modules. I have (3) 18650 batts in series (11.1v), in a holder that I have charged several times to power some prototypes for testing. I have had no issues, luckily. I will definitely heed all of your advice. Safety first!!

Thanks again

 

H

hoghunter

Member

• Jul 5, 2017

• #6

If I use one of these (see link below), can I then charge the (2) batteries in series using a std 12v wall charger, safely?

**broken link removed**

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Jul 5, 2017

• #7

That looks like just what you need - protects against overcharging (and the resulting fire risk), and protects against over discharging, ruining the batteries.

 

ci139

Active Member

• Jul 5, 2017

• #8

https://www.google.com/search?q=18650+battery+specs
https://www.google.com/search?q=charging+li-ion

 

H

hoghunter

Member

• Jul 5, 2017

• #9

Nigel Goodwin said:

That looks like just what you need - protects against overcharging (and the resulting fire risk), and protects against over discharging, ruining the batteries.

Click to expand...

Thanks, I'll go ahead and order a few.....

Thanks to all !! more questions to come......