What size battery cable for older farm truck?

[Quebecguy]

Also, is the reason for a larger wire diameter for the battery cables just for the higher current draw during starting?

A larger wire diameter has less resistance to current flow than a smaller one. A six volt system would normally have larger diameter battery cables than a twelve volt system and the larger diameter cables would not only improve starting but also the efficiency of the charging system. I guess your truck has a 12 volt system so you don't have to use giant size battery cables!

 

[sixdogs]

Yes, truck is 12V so 2 gauge should be fine. In the old days I would have gone with 1 gauge or even bigger but 2 gauge should be OK for summer drives and warm days. It won't be used in the winter.

 

[4570Man]

I know you said the old cables were pretty ragged but couldn’t you just cut the end off a couple inches and get a decent end to compare too? The cables on my truck are about 1/2 diameter including the insulation.

 

[sixdogs]

I know you said the old cables were pretty ragged but couldn’t you just cut the end off a couple inches and get a decent end to compare too? The cables on my truck are about 1/2 diameter including the insulation.

The negative one is a strap and likely original so that's OK and the positive one is an old cobbled together replacement that was likely made from some other cable. Best to start fresh.

 

[gary49]

Length of the cable matters. Longer cable=more voltage drop and slower cranking. Bigger is better but that's probably a 300 cubic inch 6 and it'll start anyway. I see you're in Canada, though. If it was me, I'd go with the larger cable.

 

[sixdogs]

Length of the cable matters. Longer cable=more voltage drop and slower cranking. Bigger is better but that's probably a 300 cubic inch 6 and it'll start anyway. I see you're in Canada, though. If it was me, I'd go with the larger cable.

I'm in Ohio, not Canada and this truck only sees the warm days of summer. Sits a barn when it's cold.

 

[EddieWalker]

The biggest you can find!!!

But remember, that's only half part of it. Be sure that where you connect it is clean and solid. One of the most common starting issues is a bad ground where the cable connects to the frame, or engine block. Sand it clean, use a new bolt, and cover everything with something to stop corrosion.

 

[sixdogs]

The biggest you can find!!!

But remember, that's only half part of it. Be sure that where you connect it is clean and solid. One of the most common starting issues is a bad ground where the cable connects to the frame, or engine block. Sand it clean, use a new bolt, and cover everything with something to stop corrosion.

Thank you. Absolutely correct on clean connections. Years ago a wiring tech guy told me that bad grounds are the cause of almost every wiring issue, especially the squirrely ones. I doubted him then but have learned to respect that belief.