purchased 2 batteries (eBay) for 2 phones. 1perfect. Mine crash/reboot cycles. new battery. Worked, but fast drain. Contacted seller, issued refund, replaced original battery. another battery- chose seller with better reviews, paid more. Weird issues similar to first battery. Worked at first, once run down, crashed wouldn’t charge. lots of testing later I realized all 3 of my replacement batteries lack any insulator on top of the metal of the battery connection point. Original battery has insulator. Read that a scratch in that insulating material can cause issues. electrical tape. Now same battery that wouldn’t go past 1% acting totally normal. confusing: if real issue, how do replacements work for anyone lacking the insulator? How could sellers overlook such simple and crucial thing? How did 2nd battery work at all while 2 others were useless? If anyone else receives a battery with exposed metal on top of connection point, may be worth a small strip of electrical tape to guard against weird issues.