First I'd like to thank Jack for his scientific contributions, I learned a lot reading his past posts and through his videos.

I understand the routing of the two 6-8awg FICM/firewall grounds, + to +, etc. My question is regarding the additional 1/0 ground cable. Does it go from the driver's side existing factory negative battery terminal to the engine block?

Much appreciated

 

Yes, attaches at the same point as the drivers battery ground, and depending on where you pick on the block, it's about a 20" cable.

 

I've been happy to do it as part of my self-therapy and thanks for dealing with my idiosyncrasy.

Yes, but I'll expand.

What I was trying to do there was to lower and match the resistance between the two batteries on the negative side. Probably the best description to date (as I've learned more) is the flow from the passengers negative terminal to the engine block involves 1 bolted connection. With the factory setup for a single alternator, the driver's battery from the terminal goes through 3 bolted connections. So the resistance at each connection is summed.

An example for illustrative purposes would be if each bolted connection were a 2:

Passenger side a 2 value.
Drivers side a 2+2+2=6 value.

And why the driver's battery works less, it has higher flow resistance.

The most economical way and my original layout were to add a cable from the frame connection to the block, and instead of it being a 2=2=4 connection, it's more like 3 because the original path is now a parallel path. And it's inexpensive with only 1 short cable, a bolt, and a washer.

You can also run from the drivers negative terminal directly to the block, a little more costly due to the longer length, it may be easier than getting down on the frame. It's a 2 1/2.

Or if the terminal at the driver's negative battery is in poor shape and corroded, a replacement cable with a terminal end going directly to the block works and ignore the fame connection. That would be a 2.

Any of this is an improvement. But it's not like it's solving a major problem, but it's getting the batteries to work more equal.

There is a better way to do all of this, but it requires all new major cables and it's expensive, not something I'd do until the need to replace all the cables. I'll do that after I figure out how to get a 6.0L back together.

 

Thanks guys! Jack, do I need to add a 1/0 ground cable from the passenger battery terminal, or just leave the passenger ground as is? I gathered in your posts that it is left as is, but just want to make sure.

 

 

 

Thank you. I have an LN alt and already measured a voltage improvement by just adding the 2awg batt to batt and a 2awg parallel cable from the alt to passenger battery. Plan to do the grounds this weekend.