My Nikon D5300 battery will not charge, even over night. What am I doing wrong?

Had the camera for about a month. Took one photo shoot, I charged both batteries I got with it just fine the first time however now I can leave it on the charger all night and it still says low battery when I put it in my camera. The continues to blink.

Could you be more detailed? It could be both, the battery and the charger fault. If you ever get a new battery, make sure you charge it fully first and let it drain fully after every charge (until camera says, battery low shutter won't function) the battery has a life. Avoid charging it over night, the nikon battery will charge in around 2 hours. Overcharging can also be a problem, just saying.

There seems to be a problem with your charging routine.

As noted, fully charge the battery before using it for the first time --- you have done that.
Unless you are planning on shooting all day the next time out (a fully charged battery will produce 600 shots or better as long as you keep the LCD off and use the camera as shown on page 18 of your user manual, using the cameras viewfinder.

The nice thing about Nikon battery chargers is that they will NOT overcharge or overheat your battery. The night before I leave to shoot an assignment, I put all my Nikon Li-ion batteries on their chargers and leave them overnight.

Two things can harm a Li-ion battery. 1) shorting out the contacts… It is important if you have the battery out of the camera, to keep it in its little plastic protector that came with it and 2) if for some reason you fully deplete the charge of the battery, do NOT let it sit for over 48 hours uncharged.

If your battery for some reason is defective, Nikon will send you a new one and you can send the faulty one back to them by return shipping.

I have used the same batteries from my Nikon D200 for over 9 years and they still work just fine in both my Nikon D200 and D300. If you take excellent care of your cameras batteries, they will last probably longer than you keep your camera (five to seven years on average)

Are both batteries not charging? If so, your charger may be broken. If one charges, but the other doesn't, then you have a battery problem. You may need to send the charger and batteries in to Nikon for warranty repair. If you are using a 3rd party battery, don't send this to Nikon or else they'll probably void your warranty for the charger.

I am having a similar problem with my new D5600. I just got it out of the box and the charger plugged in and 9 hours later the light is still blinking.