I did in fact buy a knock-off from ebay battery, but it kept it kept it's charge for hilariously little time. Had to run it of mains power permanently (ran it as a little server for a while).
Don't know your exact timing but I run basically on Dells Latitude laptops for past 2 decades. Since its just for travel and not my primary workhorse, I buy used corporate ones for pittance (cca 300$ for models worth 1500 few years before), and swap battery myself for another original OEM one, they cost less than 100$ from original manufacturer. Its just 2-3 philips screws and 1 cable, anybody can do it. They last just as much as advertised on new ones and don't degrade much even after few years.
Batteries (and ie chargers) are one of the things that's utterly idiotic to shop around on chinese portals. You literally always get what you pay for (or worse) and can't punch above this threshold.
This was mid 2010s and the laptop has long since bit the dust. IIRC this was a Dell Studio 15, but I recall checking eBay for old new stock with no luck, but it doesn't surprise me that the Dell Latitudes have lots of stock floating around ebay.
