Outer Limits 4x4 Board

Something is going wrong but i dont know why!!! My battery died last week and i went to get a new one. The type of the battery is the one that you dont have to use any more water (i dont know how to name it) so the battery is going to give power. The battery is 45 watt and when my car in not working for about a day or two when i first start the engine the Feroza is shaking like crazy. (notice that when i stop the engine and try againg to start no more earthquakes only after some days it happens). I have checked all the wiring of the car and anything else i could imagine but i havent found anything wrong. Does that happen because the batter is not big enouph? If i take a bigger one will that problem stop? Please help

Do you need to reset the ECU after the flat battery?

I dont think so because i have changed before the battery but this happens for the first time. It cant be the EC anyway because if that was the problem that would must happen every time i start the engine and not only once when i start the engine after one day. Who know i will check out next week in the Daihatsu service and they will find out. But please if anyone knows tell me.