REVISED 8-31-2022 If you are like many of us with the Sena 50S you've encountered the battery not lasting more than 2-3 hours. One of my 50S is out of warranty and the battery only lasted a couple of hours. Sometimes Carolyn would get a low battery warning within 15-20 minutes of turning it on. @6xGrins had recently done a battery change on his 50S with good results. After talking with him I tackled this little project.; e.g. the pins that go into the bottom connector are at a right angle making it difficult to disconnect. Changing the battery is the easiest part. I tried to reinstall the circuit board and could NOT get the pins to align with the bottom connector. After a bit I gave up and resorted to YouTube. I found one video that was helpful. In video, option 2 is the hot ticket. Start by applying a little heat to the bottom of the 50S where the pin connector is located. I used a heat gun. Then using an X-acto knife, pry the connector from the housing exposing the pins to the circuit board. After removing the little screws on the back side and prying the thumb wheel off I then pried the circuit board up to get access to the battery. There are 7 screws holding the housing together. 2 of the screws are smaller than the other 5. 1 of the screws is almost hidden.The circuit board is plugged into the 50S housing at 2 spots; both located on the far right hand side, I used a screwdriver to gently pry the circuit board straight up. With the circuit board out of the way, using a small set of needle nose pliers I removed/replaced the battery. Once this was done I reassembled in opposite order. FWIW, There is a sticking substance on the backside of the pin connector that is tacky so I'm comfortable the connector is sealed.
From the video, you do NOT need to remove the large rubber seal or disconnect the antenna. Do not release the antenna at any time while replacing the battery. Leave the antenna in the stored position.
From the video, you do NOT need to remove the large rubber seal or disconnect the antenna. Do not release the antenna at any time while replacing the battery. Leave the antenna in the stored position.

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