Long story short, we moved our batteries to the bed of our truck when we finished our conversion.

We picked up 15 ft of 1 gauge welding cable and ran from under the hood back to the batteries. It's not thick enough I don't think because it takes longer to crank.

What do you recommend we should upgrade to and where can I buy it?

And batteries are not the issue, trust me lol.

 

What year truck and engine? What kind of conversion?

 

2005 with a 6.0 we swapped a 12v 5.9 Cummins in because all the issues we had

 

Where are the grounds located? What kind of voltage are you getting at the battery?
Also have you seen the E-Series frame mounted kits?

 

I'm thinking it's the wire size but to confirm that take a voltage reading at the battery when cranking and at the starter, if you have a large voltage drop and the grounds are tight you need larger wire. Remember your ground has to be the same size.

Denny

 

Or, bigger?