Opinion on knock-off batteries for laptop...?

I tried that in a Samsung phone once and it flashed me a message "Not a Samsung battery" Had to take it out and go OEM.

I used "generic" batteries on a Acer laptop, works OK.

Bought an "upgraded" higher capacity over the OEM batteries that was supposed to double run time from 4 hr to 8 hrs.. Is physically larger and in the case of Acers OEM battery, the battery is the "door" of the part of the bottom of the laptop.. Didn't get 8 hrs of run time but that may be from the SSD and memory upgrades I did at the same time which uses more power..

If it fits and your laptop manufacturer did not use a battery with a identification chip a generic battery can often be used. Just be aware that the specs of generics may be a bit over stated.

The cheap third party batteries *can* be a good deal, but also they can be dangerous.

If you don't go super cheap, they likely use the same name-brand cells (panasonic, sony, etc) that the laptop manufacturers use.

However, the bad thing about cheap third party batteries is that you can't easily tell what thermal protection they have. Thermal runaway is what leads to battery fires, and even the major manufacturers sometimes have problems.

https://www.imaging-resource.com/news/2015/10/28/counterfeit-battery-fakes-with-risks

Thermal runaway problems are what's behind all the burning-computer videos we've all seen on YouTube. In the US, the CPSC (Consumer Protection Safety Commission) has logged more than 40 product recalls for lithium batteries in the last 12 years, from companies as prestigious as Acer, Apple, Dell, Fujitsu, Gateway, HP, Nikon, Sony, and Toshiba, all based on reports of spontaneous meltdowns. You can be pretty sure that these companies have been building battery packs to the highest standards, with good designs, QC procedures and protective circuitry built in, yet they all suffered instances of batteries catching fire.

If mainstream companies like Apple and Sony have had problems with Li-ion batteries, how much more likely is it that an internet counterfeiter selling dirt-cheap knockoffs would have them? And of course, forget about a recall notice; even if they cared, counterfeiters aren't about to call attention to their illegal activities by announcing problems with their products.

So, buyer beware. Don't get the absolute cheapest battery you can find as there really is a quality difference between dirt-cheap third party batteries and the OEM batteries. I usually buy OEM batteries (directly from the manufacturer if possible, because there's also a problem with counterfeit batteries sold on resellers like Amazon).

I bought one for an old 2010 ASUS and it has been working for 2.5 yrs now with no problems.

Quora has a discussion on this.

Good question and I want to know more on this subject.

Replacing my phone batteries has led to inferior performance. They were suppose to be OEM (labeled as such) but if so they could have been years old.