so my turbo s5 has charging issues the battery when the car is on is at 12.6-13 volts which I assume is low, the car runs ok but I want to address this issue, the car was bought with the battery relocated and it has one wire from the alt post to the starter and then from the starter straight to the battery positive... how can I fix this?? the alt post stays steady at 14-14.3 volts when idling/reving it up

 

When I relocated my battery, I ran from the positive terminal to a circuit breaker, then from the breaker to a distribution block. From there I have a heavy gauge (think I used 2 AWG) wire going to the starter and a slightly less heavy gauge (4 or 6 AWG, can't remember), going to the 100A main fuse. Minus the circuit breaker and distribution block, this is how the stock system is wired - one wire to starter, separate wire to 100A fuse. With proper alternator belt tension, I now see 14V+ at the battery with the car running.

For starters, I would check the wire sizes on the previously done relocation.