When I leave the fully charged battery in the camera for about 10 days it gets completely discharged. This is the original Nikon battery. I though the battery is old and bought a genuine Nikon battery. The issue is the same. My relatives have Nikon D200, D70s etc and they do not have these issues and the battery if left in camera last for more than 6 or many more weeks. How long should a fully charged battery last in the Camera ? ( I leave my camera off after use )

Mine did to i wait then it was fine! wow

I noticed that you noted that you have a new battery. Have you fully charged it? Although batteries are charged before they leave the factory, you do not know how long they have been sitting on the dealer's shelf slowly discharging. The charging time for your EN-EL10 battery is about 100 minutes. Once your battery is fully charged, try to turn the camera on again. If it still doesn't work, you may have bought a defective battery, the battery contacts on the battery, the battery charger or in your camera's battery compartment may be dirty or the battery charger may be defective.
To clean terminals, rub a clean pencil eraser across the contacts. That will remove any dirt, grime or oils that may be preventing a solid electrical contact. Once the contacts are clean, charge the battery again and retry it in the camera.
If all that fails, contact the Nikon USA Service Center at 1-800-645-6687 9AM-8PM EST, Monday to Friday.

Every rechargeable battery has a certain cycles of charging and discharging the battery. Not two batteries have the same life time. The amount of cycles a battery can have, can be influenced by the user. If you leave a battery without charging or discharging for months or even years, the lifetime can be shortened. That is why most of the time you get warranty on the equipment, but almost never on a battery. (sometimes a warranty of 90 days is given)
Still when a battery won't charge, you could check all the parts in the chain. The AC / DC power convertor / charger the power cable.
When the light on the charger comes on, you can assume the charger is working.
With your camera you charge the battery in the camera. Looks almost the same. As soon as the green light comes on (starts to flash slow) you can assume the AC adopter is working. The charging of a fully discharged battery should take about 4 hours.
If the green light goes not flash at all, check the adopter and check the USB cable. Be aware as long as the cable is in the camera, it can't be switched on. So before testing if the battery is charged, remove the USB cable.
Last but not least, if you have a multimeter, you could try to measure the voltage of the battery. It should be a little above the 3.7 volt that is printed on the battery. If not you can be sure the battery is no good at all.

found this on internet:

The batteries should be charged for at least 24 hours for the first charge cycle and after the batteries have been completely discharged. Each cycle thereafter should be 8 - 10 hours to fully recharge
https://midlandusa.com/two-way-radios/faq/ I am guessing 8 hrs would be ok,just don't leave pluged in for days

I'm sorry that the Camera is not turning ON. Please follow the below troubleshooting steps and check the operation:

1. Please make sure that battery is fully charged.
2. If the battery is not used for a while, it is possible that it may be damaged or completely discharged even if it was charged fully before. Hence charge the battery again and check the operation.
3. Remove and Reinsert the battery and check the operation.
4. Try with a different battery. If the issue persists with new fully charged battery, service may be required. You can click hear to setup a service for the Camera.

Thanks for understanding. Please let me know if you require further assistance.

most companies recommend 24 hours charge time unless otherwise state in the manuals for the camera or rechargeable batteries. while with some cameras or rechargeable batteries you may be able to use right out of the box! also if are using third party rechargeable batteries then you should follow the instructions of the battery maker.

Is this an older camera? Is the battery the original? Has it been unused for a lengthy period of time and allowed to completely discharge? It may be dead even though it registers charged in the charger. Clean the battery contacts in the camera with a cotton swab lightly dampened with rubbing alcohol.

try removing the batteries, charge them fully (or replace) and then try again

BATTERY TIPS

Now a days in LITHIUM BATTERIES are used no memory effect

always charge battery for 16 hours when first use new

never keep ur battery fully discharged for long time when u store ur camera always keep it half charged or fully charged when storing for longer period

it is good to fully discharge once in a month but dont make it ur habit

pls rate me FIXYA for help