BMW Repair: bmw emergency start, solenoid, trunk latch

Question
how to can i open the trunk with out the battery in the car?

Answer
Well that means your battery must be in the trunk.The only way of unlock it would be with the  key.It would have to have the battery in it, unless it died when it was locked.If it had a battery in it when it was locked you need to charge the battery.That can be done with the terminals under the hood.The + is marked the - is connecting to the body/engine.I have had situations where the car was unlocked but yet the trunk was still locked.It was an older 7, before they put batteries under the seat and in the trunk.I was lucky in that once it was charged up the key did unlock the trunk.Once it did I unplugged the lock solenoid to the trunk latch,so electrically it would not lock.