There are certain situations where a battery is a bad deal no matter how cheap it is. If the product has a history of recalls, stay away. If the manufacturer has no customer support—so you can't get help if something goes wrong—that's a red flag. If the battery is not rated for the current your device draws, it could overheat and potentially catch fire. That's a safety hazard you don't want on your conscience.

Also, be cautious of batteries that look like a well-known brand but are actually counterfeit. These might have unreliable protection circuits and can be dangerous. Always buy from authorized distributors, and check the packaging for authenticity marks.

Another red flag is a battery that claims to have a huge capacity in a small size. Physics doesn't lie—if it seems too good to be true, it probably is. That kind of product might have a lower quality cell that degrades quickly or even swells.

Finally, if you see a battery with a very low price compared to similar models, ask why. It might be using older cells or missing protections. In the world of batteries, you get what you pay for—but that doesn't mean you have to pay the most. It means you have to pay for the right safety features.