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%.

Tricky to install but youtube videos helped. Works fine.

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.

I installed the battery using the kit- it took some time, effort and great attention to detail but it wasn’t an impossible task. Once the battery was installed I put the Fitbit on the charger and the screen lit up, so I assumed I’d been successful in the installation. I was wrong. The battery never held a charge. The screen would start up when put on the charger and it would show the battery charging icon whenever the Fitbit was tapped or moved, but as soon as it was removed from the charger it would die.I tried pressing the reset button on the charging cable numerous times- that did not help.I also purchased two more charging cables, just to rule out any possibility of there being an issue with the cable- it was not the problem. I still produced the same results with the new chargers.After ascertaining that the issue was in fact with the battery itself and not with any outside factors, I sent the kit and battery back.What a disappointment. I was really hoping that this would be successful.