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

Gjac wrote:
I have been retired since 2004. I am now on my 2nd lap top, I always bought the 3 party batteries and they outlasted the OEM battery and the laptop itself. When my current laptop battery started to fail after about 10 years I was ready to buy another one but I removed the battery for awhile then followed some HP prompts to prolong battery life. That was about 3 months ago and battery has lost capacity but is still working. You don't always get what you pay for. I don't know if this is just coincidental but I had an old Oral B with a Li battery that would no longer charge and the company was nice enough to send me a new one. When the new one died also I put the 20 year old one back on the charger about 5 years ago and it still works today. So when one gets weak I just alternate between the two. They won't fully charge when low they have to be completely discharged to come back to full strength. Anyone know why this is?

Lithium batteries require a BMS (Battery Monitoring System) to manage the charge/discharge of the cell. The BMS is typically a very small chip embbeded inside the cell that you can't access.

BMS will "disconnect" the cell from the terminals if the charging voltage or current is too high or the device is drawing too much current or the cell voltage drops below safe low limits.

Letting a cell sit for some time may allow the cell voltage to float high enough to allow BMS to connect for charging.

Just be aware that if that old cell starts to bulge, remove it from the device and charger and for good measure since you can't often determine the exact type of Lithium battery you might wish to set outside on concrete until you find a safe place to dispose of it. Lithium battery fires are no joke.