Have you used the search utility at the top of this Page to see what others have done regarding charging problems? Have you run the batteries down to 0% ? This is a no no. At that point charging can be successful but it can also be very difficult to get it to recharge easily. Personally I have never been in that territory in 18 months. Can you be a bit more specific about what you have tried?
Since it is at 0% and likely very low voltage also, it can take several days for it to recharge. When the voltage is very low, it recharges very slow until the voltage reaches a certain level then the charging rate increases. So plug it in using the proper BlackBerry Playbook charger and leave it fir several days. If you need it fir work, leave it over the weekend and hope it is charged up fully on Monday. Try not to let the battery go below 10%, it just causes a lot more trouble.