The Samsung 3D Glasses SSG-5100GB/ZA Replacement Battery is the common CR2025.
Yes you did see red, but that's not enough and at 6 months ago, I'd try the battery next.
Been using and very happy with my UE65J9000 for last 2 yrs. Have watched a lot of 3d movies on it using the SSG-2100AS glasses that came with the set. Until recently I had had no problems, everything would work first time as expected.
Fast forward to yesterday. I wanted to watch a 3D movie. At this point I would like to say that I have not watched any 3D for approx 5 - 6mths, no special reason, just haven't watched anything. So, switched everything on, as usual, configured the TV, as usual, and sat back to watch.
This time however when I pressed the power button on the glasses they did not go dark (yes the red light flashed as before). The picture did not clear. In other words, they were not working. First thought was - battery. Nope, wasn't that (replaced with new one). Second thought - TV settings. Nope. Finally, check the Forums. Not much help there, but, I did do a reset of the TV, just in case.
In short, nothing I have done has changed anything. Still no 3D picture.
I have tried checking for the IR emitter light (using phone) but cannot see it anywhere on the whole screen, so, don't know if its working or not. Filled in the 'Help Support' form on-line from the TV and now waiting and hoping Samsung will get back to me before I PUT MY FOOT THROUGH THE SCREEN.
Has anybody else had any 'breakthrough eureka' moment with this problem that has worked?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic