Galaxy S21 Ultra Battery, (Upgraded) MAXBEAR 5500mAh 3.85V Li-Polymer Replacement Battery EB-BG998ABY for Samsung Galaxy S21 Ultra 5G SM-G998B/DS SM-G998U with Repair Tool Kit

My example was a good one and am very pleased! It took about a week for the battery to get to its design capacity. Give it some time, you won't get maximum potential right away. I used 3M double sided thin tape 8mm width for my adhesive, 2 small strips about an inch long. Taking the OEM battery out required some effort. I had to bend the original pack to remove it. The factory uses a large adhesive square, more than what was required. I didn't want that same struggle if I have to replace that battery in the future again.

This kit worked great. Not real easy for the average person to take apart a glued S21. There are good videos to help with this. You just need patience. The Maxbear battery works great so far and lasts about 48 hours with little usage. 1/2 hour internet, 45 minutes in phone calls, 50 text messages, couple pictures and standby time. This was a life saver for me because the original battery swelled up and I had no insurance. Best buy and I'm sure many others, wouldn't touch it because of the liability of these batteries leaking or catching fire. Verizon won't take swollen phones either. This $20.00 Maxbear battery saved me $800.00. If you can wait a couple days for shipping, than ordering this in a no brainer. BTW I got 1 day shipping on this Item in Portland, OR To disassemble and reassemble it took me about 1.5 hours. I went slow to get it right.

This kit is basically the cheapest junk you can get, which makes me realllly doubt the longevity or capacity claims for the battery. The package was missing parts that were shown in the photo. There are zero instructions; they actually tell you to find a tutorial somewhere online. The suction cup for pulling the case and battery was completely non-functional; it just wouldn't stick. I had to dig around the house to find one that worked. The dark blue tool was so flimsy that each corner bent when using it for its intended purpose, so it became useless pretty quick. You'd still need at least 5 of these for this job, but I only received one (I ended up using my credit cards). This also doesn't come with adhesive to maintain your phone's waterproofing. BUT, I was very patient and meticulous, replaced some of the adhesive with good double sided tape, and the phone booted right up. I'll do some capacity tests and update this review.

Kit does include most tools to get case open and get to the point of prying old battery pack out. Case is glued shut, battery is glued down. No instructions furnished, have to find on your own. Also source sealing tape or goop to hold back on after replacement. New battery did charge, so sucess.

Item works for a battery replacement, just know that the claimed mAH is total bogus. It says 5500 in the pic, and when it arrives it says 5800 on it. Then in real world testing it has just over 3000. So don't be expecting any good battery life out of it, but it will keep an otherwise scrapped phone going

Battery has great life. Perfect fit and easy enough installation. Brought functionality back to my s21 ultra 5g. Overall very pleased with this purchase. The glue they give you doesn't fit the application perfectly but its still usable and gets the job done.

battery worked no problem. The tool sent didnt work. I had to get little screw driver elsewhere to do the swap.

Saved me $1299.. decided to keep mybs23u, instead of buying a s26