I replaced my laptop batterywith one purchased on the net.When I put the battery into the computer and went into power management it say battery charge unknown. I put back my old battery and it recognises it.The reason I replaced the battery was the old one was on tis way out and it was not taking a full charge even after recycled 3 times.
The circuitry inside the battery has to communicate with the system to report it's status. Non-OEM batteries do not follow that and therefore the charge is not communicated correctly.
Recycling the Li-Ion batteries is not a good idea. these batteries do not have memory, but also do not tolerate well complete discharges. When that happens, they lose a few more cells, effectively reducing the battery's capacity every time. It works on Ni-Cd or Ni-Mh, but not Li-Ion.