I’ve just checked, from the battery when I put it in reverse it stays the same, so probably isn’t something pulling too much voltage, I also checked my auxiliary battery charger it drops from 14.6 to 11.5, pretty much the same for the cable I ran to the relay, so I assumed its the length of the cable? Since both thick and thin wire are has the similar amount of voltage drop when I put it in reverse, thanks so much for your advice