Solved PS2 AC-DC Adapter as a 18650 charger

[Arceus]

Hello everyone. I was researching and I wanted you to give me your opinion. I have four 18650 (3.7v, 2200 mAh, each one) and I would like to make a 2S 2P battery pack. (7.4V - 4400 mAh)

It would be possible in some way to charge these batteries with the PS2 AC-DC adapter that grants 8.5V, or the 900xx series psu that grants 7.4v, supplanting a smart charger?

Every two batteries with their corresponding BMS of 2S.

Thanks.

 

[Aurelio]

Hello everyone. I was researching and I wanted you to give me your opinion. I have four 18650 (3.7v, 2200 mAh, each one) and I would like to make a 2S 2P battery pack. (7.4V - 4400 mAh)

It would be possible in some way to charge these batteries with the PS2 AC-DC adapter that grants 8.5V, or the 900xx series psu that grants 7.4v, supplanting a smart charger?

Every two batteries with their corresponding BMS of 2S.

Thanks.

No.

 

[Arceus]

No.

From what I saw it is possible but I would like to see your opinion... something more formulated rather than a simple no.

 

[Aurelio]

To charge a li-ion battery (or a battery pack) you can't just apply constant voltage to it. You need to use properly controlled constant current followed by a constant voltage profile

 

[jefflongo]

It is possible, but only if your BMS handles the lithium-ion CC-CV charging characteristic.

 

[Arceus]

It cuts the charge and allows the discharge, says nothing about CCCV.

 

[jefflongo]

Overcharge and overdischarge protection is not the same as supporting lithium-ion charging. You would need a smart charger in this case.

 

[Arceus]

As I have experimented well, I was able to charge the 18650 7,4V battery pack with the PS2 transformer, and the BMS simply cut the input current while the output current remained intact. Batteries at this point maintain the charge normally, and there appear to be no signs of immediate deterioration in it. I am doubting if the smart charger is really necessary...

 

[GingerOfOz]

As I have experimented well, I was able to charge the 18650 7,4V battery pack with the PS2 transformer, and the BMS simply cut the input current while the output current remained intact. Batteries at this point maintain the charge normally, and there appear to be no signs of immediate deterioration in it. I am doubting if the smart charger is really necessary...

Dang, Mumble sure reincarnated quickly.

 

[Arceus]

Dang, Mumble sure reincarnated quickly.

Huh?

 

[Aurelio]

Huh?

Dude. Mumble is one of our members who had li-ion exploding on him because he didn't charge them properly.
You are applying a constant voltage. The BMS current limit is a safety feature to prevent shorts, so the maximum current limit is usually higher than the recommended maximum charging current.
You'll blow them up and you'll get hurt. You have been warned, you're on your own now.

 

[Arceus]

You'll blow them up and you'll get hurt. You have been warned, you're on your own now.

As you say, I can't access a smart charger because of shipping issues. I think I will switch to an external 18650 charger ... Thank you all for your help, I should have looked like an idiot.