Trecked

what does in parallel or in series exactly mean? Battery on the bike didn’t have enough juice to start it so he got another battery and made the terminals…ummm…kiss?

2009 Bajaj Pulsar/Rouser 200. Took it in for an idle/start issue. In their diagnosis, mechanic bypassed the fuses (fuse box with 2 tube fuses) and directly connected the wires (for reasons that are beyond me) along with jumping the starter relay with a screw driver numerous times. I noticed when I came back after going to the store for a few minutes. Went to start the bike and the dashboard wouldn’t come on. Bringing it up to him he seemed surprised and didn’t know why. After over 30 mins of fiddling around with the wires trying to figure out why, we take out the panel and noticed the PCB (the electrical board) was burnt. He casually says “Ah, here is the problem” as if it spontaneously happened by itself. Did it? I would now like to know if deleting the fuses coupled with jumping the starter relay AND connecting another battery to the battery already in the bike could have causes the instrument panel/speedometer to fry. Appreciate your expertise in this folks!