A few weeks ago I bought a new 3DS in a bundle from Walmart, with it I recieved a Nyko battery pack and charge base for extended battery life. The first time I attached my 3DS to the charge base it worked perfectly, but I tried to charge it again last night and this morning it's still on low battery. When I put the 3DS on the charger, the red light lit up, indicating that it was charging. This morning the same light had turned green which means it is completely charged. I took it off the charger and started it up to find the battery just as low as before and when I put it back on the charger, the lights still indicate that it is fully charged. What is going on here?
Nyko has stated that their products are not fully compatible with those of Nintendo--i.e. the charging cradle. Try fully charging your 3DS by unplugging the plastic cradle, and charging the unit directly from the cable. If that doesn't work, there may be an issue with your battery or power supply.