3rd light up is blinking on battery. Won't charge.  Anyone know whats up?

If it blinks twice per second then an overcharge has been detected, If it blinks 3 times per second then it means over-voltage charger detected.
Have you been using the DJI charger?

Please refer to Jenee 2's reply, make sure that which is your case. After the charging protection issue is resolved, please press the button to turn off the Battery Level Indicator. Unplug the Intelligent Flight Battery from the charger and plug it back in to resume charging.

I only use DJI charger.
Go4 says
1) "Battery Cell Error".  
2) "Solution... do not power off the aircraft unitl discharging it to 5%....  Restart and sync the flight data. Contact DJI support as soon as possible"
3) "Battery cell broken. Land and replace battery"

marciano Posted at 4-15 16:34
I only use DJI charger.
Go4 says
1) "Battery Cell Error".  

Hi marciano, I am sorry for the issue. Have you tried to drain the battery and charge to full again?
If the error persists, and the battery is within the warranty period, please send the battery back for service. Please contact our support at http://www.dji.com/support to start a case.

Jenee 2 Posted at 2017-8-29 21:34
If it blinks twice per second then an overcharge has been detected, If it blinks 3 times per second then it means over-voltage charger detected.
Have you been using the DJI charger?

What do I do when to make it stop tho