How to reset pram

Also remember that once you do that the MAC will loose it's memory of the battery charge curves. To teach it you should do a full charge, then unplug and do a full discharge until the mac shuts down. Then let it alone for 2 hours for the battery to settle. Charge it with the Mac off until the green light lights. Unplug, wait 1 hour and then turn it on, plug in the power adapter and the mac now knows how long it takes to charge the battery and it's capacity.