Laptop battery without BMS

neilmc

neilmc

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Joined
May 22, 2017
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124
I've had an evening of extracting cells while half watching youtube videos.

I came across my first ever after market replacement pack with no BMS. Generic corner cutting at its finest :)

Just 3S2P with a positive and negative wire directly to the external connector. Interestingly all of the cells were near 3.4v, but maybe it hadn't seen much use before being discarded. The cells are marked BAK which are one of the decent Chinese cell makers, so they're in my testing pile.

Edit .... probably a bigger surprise from a generic pack was one that I opened containing cells marked FST 2200mah Made in China. I've tested 3 out of the 6 and they've all come up near 2400mah.
FST may be these guys, but I hadn't come across them until today:

http://www.firstbattery.com/
 
neilmc said:
I've had an evening of extracting cells while half watching youtube videos.

I came across my first ever after market replacement pack with no BMS. Generic corner cutting at its finest :)

Just 3S2P with a positive and negative wire directly to the external connector. Interestingly all of the cells were near 3.4v, but maybe it hadn't seen much use before being discarded. The cells are marked BAK which are one of the decent Chinese cell makers, so they're in my testing pile.

Edit .... probably a bigger surprise from a generic pack was one that I opened containing cells marked FST 2200mah Made in China. I've tested 3 out of the 6 and they've all come up near 2400mah.
FST may be these guys, but I hadn't come across them until today:

http://www.firstbattery.com/
Click to expand...

I'll share my experience, I just had 4 of them yesturday evening. They are right now on test.
I posted the full spec ready to be added into Cell Database
 
mike said:
Did you take pictures before you removed the cells? That sounds scary as hell...
Click to expand...

I didn't sorry. Just rip and tear like the others.

The cells might be half decent but that might be the sort of pack behind these sorts of news stories:

http://www.abc.net.au/news/2017-07-...-serious-injury-after-laptop-explodes/8738358

Tostaki said:
neilmc said:
I've had an evening of extracting cells while half watching youtube videos.

I came across my first ever after market replacement pack with no BMS. Generic corner cutting at its finest :)

Just 3S2P with a positive and negative wire directly to the external connector. Interestingly all of the cells were near 3.4v, but maybe it hadn't seen much use before being discarded. The cells are marked BAK which are one of the decent Chinese cell makers, so they're in my testing pile.

Edit .... probably a bigger surprise from a generic pack was one that I opened containing cells marked FST 2200mah Made in China. I've tested 3 out of the 6 and they've all come up near 2400mah.
FST may be these guys, but I hadn't come across them until today:

http://www.firstbattery.com/
Click to expand...

I'll share my experience, I just had 4 of them yesturday evening. They are right now on test.
I posted the full spec ready to be added into Cell Database
Click to expand...

FST? cool. I'd heard of BAK before, but not FST. I was surprised to see the FST cells test 200mah above their marked capacity.
 
FAST batteries are mostly used in certain brands of power banks.
They're mostly known for being one of the only Chinese manufacturers to make 20650 sized cells.
They're safe, but not using a BMS in such a high power device such as a laptop is very dangerous.
 
Tostaki said:
Had less luck : 1451, 1857, 1957 & 2055 mAh
Tested with Opus charger
Click to expand...

I wouldn't be surprised if I was lucky to get an unused battery. Despite the lack of BMS, the cells were balanced and they were sitting around storage voltage.
 
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