Re: Battery Packs
I don't want to name names here, but I do tend to shy away from batteries through some online retailers that may ship on slow boats from certain countries across the Pacific. Some are good, some have been really bad.
The best third-party batteries I've had experience with come from a national retailer that has both an online store and brick-and-mortar locations. They carry a wide supply of batteries, many of which are store-brand labels made by the bigger manufacturers like E******** and D*******. Some of the batteries are manufactured by their own facilities. This retailer has their main product as part of their name.
I know there are other companies that make good quality batteries. If you look online for news stories about so-called hoverboards, you can see some nightmares about cheaply-made batteries that can't withstand the kind of rough ride novice riders give them. The chemical reactions inside a lithion-ion battery are pretty intense. If the battery is made with sub-standard materials or poor manufacturing quality, it may well destroy the device you are powering.