Chosen Solution
Would be amazing to have a guide on how to replace the battery, after 1year of use the battery is really bad and the headphoes only works connected via the usb cable.
So I just performed this repair. On amazon they now have HS70 batteries. Some of them are wired correctly. Others tell you to swap the RED and BLACK cables on the connector. https://www.amazon.com/s?k=HS70+battery&… You pull off the cups on the RIGHT side of the headset. Remove the small screws, then GENTLY, lift the speaker off the board, and leave to the side, there is VERY thin copper cables to the right speaker. You then unscrew the PCB that the battery connects to. Take care NOT to bend the pins when removing the battery connector from the PCB and the battery. Then gently remove the battery, it is glued in. Do not puncture the battery. In my case the battery was pregnart/swollen. Then install your new battery, connect the battery cable again, carefully not to bend pins. Then install the PCB. Take care to make sure the wires/cables are in the same orientation and not tangled/routed incorrectly. Take a picture before you remove cables. Your new battery wire might be a bit short, so you may need to flip the battery so you can keep everything tidy. Re mount the pcb with its two screws. At this point I would try charging/turning on your headset before you fully close it up. If it boots from the battery, it may only last a minute or two. Then finish attaching the speaker, attach the cup, then charge for awhile.
I have the same issue, i have had a little look on youtube and you can remove/ replace the padding easily as it just clips on and off. When you do this it uncovers the screws. I would suggest that the battery replacement is fairly straightforward from there however you are gona want a reliable battery from a reputable source as a battery exploding in you headset would not be fun! I havnt done it as ive no idea how to source the battery .
I made this repair today without too much difficulty. I watched the following video to know what to expect. I kept the speaker attached to the cup which made the repair a little awkward to navigate, but nothing major. https://www.youtube.com/watch?v=Ju4J-ZwK… Gentle work with a plastic spudger will remove the right cup with a series of loud pops, then 8 screws to open the Power Button (right) side of the head phones. I used two jewelers’ screwdrivers to remove the power connector of the original battery, which is held in place with generic VHB double-sided black tape underneath. Mine had begun to swell so this was a delicate operation with soft tools so as not to puncture anything.
As noted in the video and above by Israel Lopez, make sure the polarity of your battery connector matches the replacement. Mine did not, and I had to very gingerly remove the red and black pins, bend their retaining clip up a little (doesn’t take much) and reinsert them into the JST connector to match the original. I did not find a need to remove the headphone PCB. At this point I connected the battery before securing it down to make certain the headphones powered on. When they did, I secured the new battery with double-sided tape, placed a small, inside-out roll of painters tape on the top to sit between the speaker magnet and the battery itself, and reinstalled the cover with its eight screws, then the ear pad with another series of loud pops. jayeffs battery information above is phenomenal, and with it I found this ~$7.00 1800mAH battery that fit perfectly with no modification necessary, and is a significant capacity upgrade.
https://www.amazon.com/dp/B08Y6R2GMQ “EBL Replacement Sp 803048 Battery 1800mAh for Infant Optics DXR-8 Video Baby Monitors, High Capacity 3.7V Lithium Ion DXR-8 Rechargeable Battery”
