When you start the car the engine surges with no power

Hello, often times if your vehicle loses battery power for an extended period of time, the "adaptive strategy" of the engine's processor has to relearn proper operation. I would recommend ensuring you have and maintain a fully charged battery now and run the vehicle for a bit yet until things likely settle down. If they continue to be a concern, there could be an engine performance issue due to something reading improper information and the processor adjusting accordingly to compensate for the improper reading. Testing would be needed in that case to find out what is going on. Run the vehicle a bit first though.