36mAh Battery Replacement Compatible with Fitbit Alta Activity Tracker and Smart Fitness Watch FB406

I read many reviews of this and i admit, i was Very skeptical. I am leaving a review because i'm not sure if people know how to fix it.Scenario: I have a Fitbit Alta, must be about 4 years old. After 2.5 years the battery would not hold a charge at all. eventually it wouldn't even turn on plugged in. I tossed it to the side as it was not usable.Fast forward - January 2020 . New years resolutions: 1. Lose weight 2. Spend less.Prices of new devices are expensive, after looking around i figured it'd be worth a shot to fix my Alta for 1/10th price.I ordered the replacement kit and It showed up a few days later.First time opening the Alta, was a little tough. There are many videos of people using heat guns and such. I did not use anything but my thumb finger nail to get the screen cover lifted. Once i could put my finger nail underneath it fully i used a pry tool supplied with the kit.Taking off the screen wasn't too bad, pry evenly with the tool from the kit. There is only a piece of tape holding it on.Once the screen is lifted, there is one screw holding the board down. The kit has the screw driver for this. It a very tiny torx (and i did not have that size in my iphone/droid repair tool kit). Note: the Alta chassis has a couple brackets that hold the board on one side.I pulled out the trusty Weller soldering iron and took off the old battery. I used tweezers to pull of the double-sided sticky tape used to hold the battery in and stuck to the inside of the Alta. I put the battery in, carefully cut the wires to proper length and solder wires.I put it back together. NOTE: the screen cover needs to go back in a certain orientation. There is a pin that makes contact to the screen cover, so just line the two up (you will see a little metal contact on the screen cover).After putting the battery in it did Nothing. I plugged it in waited a few minutes. Shook it. ...Nothing. I left it plugged in for an hour or two, still nothing.In order to turn it on, i had to send a reboot sequence via the charger. Yes, there is a button on the USB end that you need to press in a sequence of 3 times. I left it plugged in and kept pressing it 3 times (within 8 seconds), like SOS in morse code. After a round of that BAM! it booted up.So i put a full charge on the battery and i can use it for about week without a recharge just like new.The image, is about 4 days of use and @ ~50%.

Battery works as intended! I was a little worried that I would not have the skill required to replace it but it was not hard. My watch only worked when plugged in. Off the charger it would not light up. To take off the face plate I used a razor blade. The included screw driver to pull out the board. I did not trim the wires on the new battery. Stuffed everything back in and charged it up, working fine! There was a helpful YouTube video that led me to this listing.

Read my erroneous original review below. If you are experiencing the same problem of the new battery appearing not to fully charge and the Fitbit only staying on while on the charger (as other reviews have also reported) there is a good chance you have accidentally shorted out your Fitbit while removing the old battery or installing the new one. There is a micro-fuse on the circuit board labeled "F1" that can be seen using magnification. This gets blown easily and you'll not be very successful in trying to replace it since it's soldered to the board and is so small. Your best option is to bypass the fuse by applying a bit of solder across the leads of F1. This will restore operation of the Fitbit. Be careful not to apply pressure to the leads since you may accidentally push the fuse out of the board. Also make sure the gold dot on the inside of the plastic screen cover is positioned over the microswitch when you put the Fitbit back together or else it won't power up at all. Changed my rating from 1 star to 4 taking off a point for the useless plastic prying tools that come with this. They are so weak they just bend instead of opening the Fitbit. Fortunately, I had better quality tools already. The only useful item is the T2 Torx driver that you need to remove the circuit board to access the battery. All that said, I'm back in business.------------------------------I ordered two batteries to replace the OEM battery that only lasts 1.5 days instead of the 5+ it should. For some reason they were shipped separately. When I received the first, I installed it and put on the charger. It appeared to be working and the Fitbit would cycle through screens while on the charger. Next morning battery had still not reached a full charge and the Fitbit would not wake up if removed from the charger. When put back on the charger it would reboot with a slightly lower battery level. If I tapped while on the charger and removed while the display was still active, the Fitbit would stay on and work until I let the display go to sleep, and then it would die until put back on the charger. Hopefully the second battery will be from a different lot and actually work. From the reviews, it's a bit of a coin toss if you will receive a good battery. Li-Po batteries have specific storage requirements and it's likely this manufacturer/distributor is not properly caring for their inventory. I'll update results with the second battery ASAP and will be returning one or both batteries accordingly.

Yes, it's difficult to install but after watching the videos on YouTube, I had no problems. TEENY working space but that's not the product's fault. After hooking it up and making the delicate solder connections, the Fitbit Alta lit up! Per the video, I connected it before sealing the Fitbit back up. Things indicated that it was charging. But then, things went south pretty quickly. The Fitbit got very hot...more so than normal. I took the Fitbit apart to check for anything that might be grounding the case (I am a HAM radio operator) and plugged it back into the charging cable. NADA, kaput, bupkis, deader'n a doornail. Me thinks the temperature fried the components. There goes a $$$ Fitbit and another $14 for the kit. GRRRR