Battery replacement problem HP17-P150SA

I have recently fitted a none hp battery to my hp laptop (n/p N7K12EA). The new battery is from a reputable supplier and when fitted the laptop starts up normally and runs normally (both on battery and with the a/c power supply). The battery charges and all indications are normal - including the HP Support Assistant battery detailed information. However the HP Support Assistant also flags up that the battery requires "calibration" (even though it also reports that the battery is functioning normally!). Following the "calibration" procedure has no effect and the message is retained. Now for the real problem.......shutting down is normal BUT when I restart the screen remains black and there is a failure to boot up....... although, I can hear the fan operating!...Now for the oddity......if I momentarily disconnect the battery and replace it I can then start up and run absolutely normally and all is well (except for the HP Support Assistant still suggesting that the battery requires "calibration"). Following shut down the start up problem returns and it can again and again and again...............be sorted by momentarily disconnecting and reconnecting the battery.......frustrating! If I refit the "old" hp battery the laptop behaves normally although the battery is holding little charge (the reason for buying the replacement!). Any ideas?