bad start sometimes

I just installed my odyssey battery behind the front bumper and fusebox is behind the glove box. Now it doesn't start as easy as it used to. I had some problems before, that was due to a bad main relay.
So the wire from the starter to the + is the same lenght and diameter.
Ground is the same lenght and diameter.
and the one from the alternator to the fusebox (which is now inside) is also the same lenght and diameter.
So that leaves the wire from the fusebox to the + terminal. That is now longer but kept it the same diameter.
Yesterday it started but stalled almost right away the first time, then it fired up the second time. Drove it for just under a mile and it stalled. Tried starting it, didn't go on. Second time it did and I could drive it home without problems.
Now this morning it started but again it stalled almost right away. Second time no problems and drove it to work without any issues.
I always wait for the fuel pump to stop making noise before I start. It has a new main relay.
Voltage for the battery was 12.75 I believe when I checked that yesterday.
What could this be? Ignition going bad, or the dizzy maybe.
So the wire from the starter to the + is the same lenght and diameter.
Ground is the same lenght and diameter.
and the one from the alternator to the fusebox (which is now inside) is also the same lenght and diameter.
So that leaves the wire from the fusebox to the + terminal. That is now longer but kept it the same diameter.
Yesterday it started but stalled almost right away the first time, then it fired up the second time. Drove it for just under a mile and it stalled. Tried starting it, didn't go on. Second time it did and I could drive it home without problems.
Now this morning it started but again it stalled almost right away. Second time no problems and drove it to work without any issues.
I always wait for the fuel pump to stop making noise before I start. It has a new main relay.
Voltage for the battery was 12.75 I believe when I checked that yesterday.
What could this be? Ignition going bad, or the dizzy maybe.