If you go for cheap stuff, Aliexpress is better in the sense that the feedback there is usually much more descriptive and helpful compared to eBay.
- If you buy from Aliexpress, check “Buyer Questions & Answers” below the product description section. The “Buyer Questions & Answers” section does not exist for many products.
- After you check that, click on Feedback, and then on “Additional Feedback”
If anyone’s battery exploded, those are the 2 places they would most likely report about the incident.
If you won’t find anyone saying their battery exploded that does not mean it has not happened. If a person is unaware of those 2 things (“Buyer Questions & Answers” and “Additional Feedback”) or if they don’t care, they would not report about it.
But in those 2 places people who have bought, received and used the product for some time, have the option to tell about their experience with the product after they have submitted their (initial) feedback.
9800 mAh is guaranteed to be false capacity.
If you search for “18650 3400 mAh”, those seem to have more likely real capacity. For me, many of the 3400 mAh ones show higher shipping cost than the fake ones, however.
How to find the real capacity of a 18650 battery:
Search “18650 tester on Aliexpress”, those cost 2-3 USD.