PSA: This is why you should avoid Ultrafire and sketchy Chinese batteries. There's no protection circuit, despite their claim, and their advertised capacity is 9 times what they're capable of. : r/flashlight
Which 18650 battery is best for an e-bike?
18650 9800 mAh Chinese Cells/Batteries Thorough Review Yes, They Are A Rip Off GTF/GIF - YouTube
Testing more 18650 Li-ion cells (REAL vs. FAKE) - YouTube