Anyone completed a battery repair/replacement?

I agree with the above and got it working again.

Its a %#*@ hard unit to open up, you need to pry the covers off the sides of the unit as well as the one on the handle. Take the screws out and then pry open the lower handle enough to get the battery unit out. This saves taking off the blue end of the unit where the part is that hammers.

I just attached a 6volt battery into the circuit (positive to positive etc) and it was enough to get a bit of a charge and shock the batteries into charging again when you plug it back in. I'm sure a 12 volt battery would have been better but thats all I has and it seemed to work.

Good luck.

Wanted to post an update here since it looks like h1791story hasn’t yet.

I was having a problem with my unit showing that it was charged to 100%, but once disconnected, it would not turn on. When I would plug it in again, the charging indicator showed 0% and the process would reatart

I opened my Theragun Elite and tested the 18650 batteries with a multimeter - read as 0.3 V each, so this confirmed that there was a problem with the battery to the point where it wasn’t able to be recharged anymore. It seems the internals are not truly in sync with the battery, so it would read as charged to 100% even though the battery was not accepting charge at this low voltage.

I am a beginner at spot welding and handling 18650 batteries, but it was fairly easy to disconnect the 3 native batteries from the circuit and spot weld 3 new batteries (I purchased 2500 mAh 20A from bulkbattery) that were in series. I wasn’t able to record, but there are tons of guides on YouTube on how to spot weld 18650s, so I would reference any of those.

Once connected, the unit works again and also has an accurate charging indicator. Hope this helps someone - I am an absolute beginner with DIY projects but this was very manageable and fun to learn about the capabilities of 18650 li-ion batteries. Happy to answer any questions!

I just repaired one and It was hard to get it apart. The battery was a 3 cell and soldered on. 2 of the cells dropped below the cutoff voltage and the unit wouldn't charger I was able to get the unit apart just input to let the battery pack hang out. I cut the plastic off the battery and used a cheap charger to get each cell up to about 3v. The unit started taking a charge have I got the voltage up.

Yes today was easy all did was shock battery already in and worked instantly used ryobi 18v drill battery

Yes open device up and the battery fine it just needs little jump with wire from 18v drill charger just tap on battery port few times will start charging again

@brandonbui74869 are you in the UK? I have exactly the same problem with mine and I haven't got a clue on how to fix it. I am female (I know that's not a good excuse) but don't believe I would be able to do it

I have a Theragun PRO Generation 4. My batteries are only charging to about 25% and their life when massaging is miserable. Therabody tells me they don't make replacements anymore! I thought Apple was bad! I found this article and was optimistic. I have removable batteries. I'm looking at my battery enclosure, but I'm not sure how to 'crack' it open. It has an endcap that is rounded and is the part on the exterior when inserted into the Theragun. I was able to pop this off without much difficulty. Now I'm looking at the long tube the batteries are enclosed in with 'cracks' up each side. Do I just pry on these with a nylon case opener? I don't want to break the battery enclosure since I can't get replacements from Therabody. They have useless customer service. Thanks in advance! This would definitely prolong the life of my Theragun! It's still great except for the batteries. I even considered converting it into a pluggable, but that ended up being more work than I wanted.

There are some videos on YouTube that show how to take apart a Theragun. Removing panels on a Theragun to repair a Theragun (Fixing a Theragun)

There's a lot of mentions regarding essentially jumpstarting the dead battery cell (the 3 18650's soldered together) on the Theragun Elite, but I'm seeing a lot of conflicting info online where it's not recommended to do something like that due to the fact that if the batteries have discharged to a level where they cannot hold a charge, the chemical changes the battery undergoes makes it dangerous to revive. That is, fire/explosion risks.

Anybody more experienced with batteries/18650's that can shine a light on this? Debating if it's worth it to perform something like this or to get new batteries altogether.

-- UPDATE --

For anyone running into this post in the future, I can provide some data-points on my theragun elite.

Had a brand new gun sitting unused for 3-4 years. Opened it up and it wouldn't take a charge. It would take 10+ hours from 0-100%, and once unplugged, drop back down to 0.

Followed some helpful comments here and https://www.youtube.com/watch?v=_-uEJRH-... to get the gun opened, pulled out the battery and unwrapped it.

You will need a multimeter. Multimeter measured voltages of each cell at 0.2-0.3V each. Didn't have any other special tools on me other than a wire stripping tool and an 18650 battery charger. Harvested a working 18650 battery from an old laptop battery (you should buy one if you can't find a spare), measured it at ~2.6v and thankfully it charged up fully with the battery charger.

Stripped an old usb charging cable and pulled out the red and black wires for positive/negative charging. They were extremely thin but worked. Followed this video https://www.youtube.com/watch?v=orvdFk23... and used the wires to connect each cell of my battery pack to my fully charged cell, and got them each to ~2.5V. Plugged in the massage gun charger and this time around, started charging really quickly.

Constantly made sure batteries did not get exceedingly hot. One of them were slightly warm at most. At ~50% charge, I unplugged the charger and let it sit for an hour/overnight. Both incurred a 0.02V drop which I was happy about. Charged it up to 100% and each cell measured at ~4.10V. Gun started up and works fine now.