I'd say this could apply to any other Nikon DSLR that also uses the EN-EL15 battery (I don't know about the EN-EL15a though).. This isn't the first Nikon camera and/or first I've had issues with batteries that seemingly wont charge up properly,, but hang on a second,, or should I at least say - that doesn't show up as 100% charged when placed into the camera..?? Let's make that distinction first, ok, because I don't know which is the real issue here..!!
The current camera in this discussion anyway, as you might be able to tell, is the D600 (I also have a D750 but that uses the EN-EL15a and hasn't showed this problem). For a while now, like approx 18 months to 2 years, I'd charge the batteries up (camera and grip) and neither of them showed 100% when placed back into the camera. They will always read as between 75 - 85% charged, EVERYTIME.. I kind of accepted it as normal for older batteries (had the D600 ever since they came out) and was ready to buy new ones, but then I thought the fact that they both went downhill at the exact same time (after being left in the closet for up to 6 months without using it),, to be a very strange co-incidence,, too strange to be normal. They each still had plenty of life still left in them but I charged them both anyway and this is when it all began. Both now showing approx 80+/-%.. After a couple of weeks of using them and charging up to an indicated 80% or thereabouts, I stumbled over the fix.. Just put them back into the charger and wait until the light stops blinking again.. First charge might be take up to a couple of hours, depending on how flat it is, but, the second charge I'm speaking of here, only takes about 5 mins or less. Now place back into the camera - voila - 100%...!!! This has worked every time ever since, including right here/now just before I typed this out. I've been meaning to post this for a year or so but just never got around to it..
You could possibly draw several conclusions from this,,
1. That the batteries actually charge up to 100% but the chip inside them is at fault, not giving the correct info to the camera first time.
2. That the batteries do not charge to 100% and the chip reports the correct info first time, but the second charge fools the same chip into giving now incorrect info to the camera.
3. That the batteries actually charge up to 100% but the camera's firmware is not reading the initial info correctly.
4. That the batteries do not charge to 100% and the camera's firmware is receiving the correct info the first time, but the second charge is now fooling the firmware into displaying 100% incorrectly.
5. A combination of the above.
6. Something else entirely, as yet unknown.
I suspect that the batteries actually do charge up fully because the camera seems to have plenty of life each time I use it,, usually for long sessions each time and the camera doesn't get switched off until I am finished for the day. Personally, I suspect either conclusion 1 (most likely), or conclusion 3 (a close second) to be the root cause..
Please forgive me if this sort of info has already been posted by anyone else..
Nikonitus
The current camera in this discussion anyway, as you might be able to tell, is the D600 (I also have a D750 but that uses the EN-EL15a and hasn't showed this problem). For a while now, like approx 18 months to 2 years, I'd charge the batteries up (camera and grip) and neither of them showed 100% when placed back into the camera. They will always read as between 75 - 85% charged, EVERYTIME.. I kind of accepted it as normal for older batteries (had the D600 ever since they came out) and was ready to buy new ones, but then I thought the fact that they both went downhill at the exact same time (after being left in the closet for up to 6 months without using it),, to be a very strange co-incidence,, too strange to be normal. They each still had plenty of life still left in them but I charged them both anyway and this is when it all began. Both now showing approx 80+/-%.. After a couple of weeks of using them and charging up to an indicated 80% or thereabouts, I stumbled over the fix.. Just put them back into the charger and wait until the light stops blinking again.. First charge might be take up to a couple of hours, depending on how flat it is, but, the second charge I'm speaking of here, only takes about 5 mins or less. Now place back into the camera - voila - 100%...!!! This has worked every time ever since, including right here/now just before I typed this out. I've been meaning to post this for a year or so but just never got around to it..
You could possibly draw several conclusions from this,,
1. That the batteries actually charge up to 100% but the chip inside them is at fault, not giving the correct info to the camera first time.
2. That the batteries do not charge to 100% and the chip reports the correct info first time, but the second charge fools the same chip into giving now incorrect info to the camera.
3. That the batteries actually charge up to 100% but the camera's firmware is not reading the initial info correctly.
4. That the batteries do not charge to 100% and the camera's firmware is receiving the correct info the first time, but the second charge is now fooling the firmware into displaying 100% incorrectly.
5. A combination of the above.
6. Something else entirely, as yet unknown.
I suspect that the batteries actually do charge up fully because the camera seems to have plenty of life each time I use it,, usually for long sessions each time and the camera doesn't get switched off until I am finished for the day. Personally, I suspect either conclusion 1 (most likely), or conclusion 3 (a close second) to be the root cause..
Please forgive me if this sort of info has already been posted by anyone else..
Nikonitus