
Anyone please help me my 2003 250 sl had a flat battery so like a twat i thought i would buy a new one and try to change it myself

this is when the nightmare began, i disconnected the old one easy then connected the new one up but on the wrong terminals

there was a spark so i quickly pulled the positive lead off! checked the fuses, and i had blown the 20 amp one under the seat so i changed that for a new one and correctly connected the battery again.
However then i went to start my bike turned on the ignition and nothing no lights nothing, i checked the fuses in the glove box and there all fine

ANY IDEAS WELCOME AS IM GONNA
