Hardware Random shutdowns (not the battery glitch)

[TurdPooCharger]

The old battery is around 37g (cant guarantee its accuracy). New one is charging right now. Just from having both in hands, Id say the new battery is slightly heavier.

That's good to know for initial assessment. Now, to figure out if this will solve your shutoff issue after enough gaming sessions. If this does not, we would be looking at disassembly and testing the micro-fuses with a multimeter. ← Oww.

Yes, I do. But see above: My batteries have not arrived yet: soon™. Grrrrr!
I will measure the weight and the running time in O2DS and O3DSXL and post the results as fast as possible.

If my German language teacher was anything to go by, I take it you will naturally be punctual and precise in your battery testing, yes? Please do take all the time you need; no rush.

 

[MaladroitJoypad]

this will solve your shutoff issue after enough gaming sessions

I hope it will. If that is any good sign; hadnt had a sudden shutdown since I kept the 3ds plugged to the charger.

 

[KleinesSinchen]

Test results:

Old Nintendo SPR-003:
67.8 mm long, 37.9mm wide, 6.9mm thick, 37g on the (cheap) kitchen scale.
New celltronic replacement:
67.8 mm long, 37.8mm wide, 6.7mm thick, 38g.

Old Nintendo CTR-003:
53,6mm long, 37,8mm wide, 6.7mm thick, 28g
New celltronic replacement:
53,5mm long, 37,8 mm wide, 6.7mm thick, 29g

Both replacement batteries fit perfectly into the consoles. Not surprising; they have very precise dimensions – like the original. The discrepancy in thickness of the old SPR-003 probably means my very, very used battery started inflating moderately after several hundred cycles since September 2012. It was about time to replace it.

Moderate shaking and dropping the devices half a meter onto a mattress makes no problems. Both DS systems continued to work with the celltronic batteries.

Test devices O2DS and O3DSXL. Conditions for running time test:

• Brightness level 3
• Sound volume about 50%
• Playing “Super Mario 3D Land”
• Wireless off
  
• Power save mode off, 3D on (both O3DSXL only of course)

The O2DS ran about 5:20h
The O3DSXL ran about 4:40h​

I stopped the tests when Rosalina menu reported about 4% remaining to avoid real deep discharge (and stop the annoying red blinking).
I noticed a different speed in the decrease of percentages. The percentage in Rosalina is AFAIK more or less based on a voltage meter. I don’t think the 3DS has a coulomb counter (“smart battery”) that needs to be calibrated. Nevertheless I will repeat the test once more in the following days. With the original batteries my devices tented to stay longer on high percentages while the decrease speed gets faster when below a certain point. The third party batteries showed both another behavior: The got relatively quick down to 80% and from there on the decrease speed got slower. Probably a little different chemistry.

Conclusion: Both batteries are satisfying and delivered the expected results [Wikipedia]. Future usage will show how long their service life is.

Edit: I never updated this. Shame on me!
Both batteries are still performing well.