They will boot without the battery, as long as the charger can deliver power. You can't reset the SMC if you can't turn it on, so you really didn't do anything. The other advice is clueless nonsense. Neither of those things will make a difference. You would hear the machine start up even without a powered display, and the battery makes no difference. If it was an issue with the connector, you wouldn't be able to recharge a good battery anyway.