Well it's done. Battery is in the truck (right rear well). 1/0 gauge feeding down the passenger's side inside the vehicle. I installed a bulkhead stud in place of the grommet for the old 8 gauge (that used to feed the interior fuse box). Both fuse boxes are fed with 6 gauge cable. The factory starter wire was 6 gauge so it stayed. I replaced the factory engine ground cable and relocated from the block to the back of the cylinder head as this was easier with headers and got the cable out away from the heat. The alternator is connected via a 2 gauge wire. Everything is in and even the rear storage compartment cover fits as it should.

Long term, I need to make a battery tie down so it's "mounted". I also plan to cut the bottom out of the rear storage compartment so I can drop the battery another 1 or 2 inches as well as probably add a piece of aluminum to reinforce the tub. I'm not worried about the fiberglass tub cracking under the battery weight, but a little piece of aluminum wouldn't hurt and would help with the battery tie down.


Pictures:

Engine compartment side of bulkhead stud (alternator, starter and engine fuse box cables connected)


Interior side of bulkhead stud (main 1/0 cable and interior fuse box connected)


Engine ground cable relocated (the black shrink tubing didn't arrive yet)


1/0 gauge battery cable running along the passenger's side interior


1/0 gauge battery-to-frame connection. I purchased a stainless M10 flange nut and bolt. I then machined the hex off the flange nut, drilled a hole in the fame and welded the nut in. Again, shrink tubing will be added once it arrives.


Battery in storage compartment


Storage compartment lid clipped down like it always was.

 

Nice clean work

 

Looks good, very cool.

 

Did you have to install a vent tube?

 

What is the purpose of relocating the battery?

 

Great work. I would recommend some heat shrink for the ends of the wire where they enter the terminal. Use the kind with the melty hot glue inside so the wire will be sealed. Since it's open to the wheel well especially on the negative cable you'll want to avoid water getting into there and corroding the cable. Eventually that will corrode between the wire and the terminal and you'll have issues.

EDIT actually looks like you're way ahead of me! Extra good work

 

Several:
- Better weight distribution
- Get the battery out of the engine compartment (less heat = longer life)
- Make room for a dry sump oil tank for the LS7 that's getting swapped in down the road ​​​​​​​



Yup, it's going to get done. For whatever reason, the red shrink tube got delivered but the black didn't. As soon as I get it, I'll go back and shrink them up.

 

You are going to need to tie the battery mounting to the frame somehow. I would NOT want the battery mounted to anything that is not tied into the frame.

 

No. Optima batteries don't off-gas.

Per Optima: DOES AN OPTIMA® BATTERY EVER GAS?


As I said, I'm not worried about it. The fiberglass is of decent thickness and with a piece of 1/8" aluminum on the underside reinforcing it, it's not going anywhere (it would have to pull the aluminum through the fiberglass).

The battery is down low in a compartment so even in a wreck (if the fiberglass somehow cracked), it wouldn't go flying. But that's just my perspective so if someone can show an actual reason why it would need anything else, I'm willing to listen.

 

Hopefully you never find out if the fiberglass is strong enough. I am just a believer in doing it right the first time. There is a reason they mount them to the frame from the factory.

 

"Doing it right" is subjective.
- Fiberglass boats and aircraft mount things (including batteries) to the fiberglass structure all the time.
- From the factory, C3 Corvettes had their battery in a battery compartment in the right rear and unless I'm mistaken, the well was only fiberglass. Based on what I've observed, the C3 fiberglass is significantly weaker than that of the C5.
- C6 Z06 and ZR1 mount their battery in the the rear compartment from the factory. From what I've seen, there is a small bracket that helps to support the bottom of the well but it's only on the edge (not a bad idea) and it's primarily the fiberglass that's carrying the weight. DIY Battery Relocation on a C6 *Pics Inside* (non Z06)

The biggest issue with mounting to fiberglass is that bolts can be pulled through. Provided the fiberglass is backed with a sufficiently large washer/plate/etc. to prevent the bolts pulling through, fiberglass is plenty strong.

So from my perspective and experience, the fiberglass well itself is plenty strong to support the battery weight. I may yet add a support, but before I did that I'd cut the bottom out of the well and lower the battery a few inches.

But as always, to each his/her own.

 

I am not arguing the fiberglass can hold the weight of the battery. Its what happens if you get into a accident. Ask any experienced car builder where the battery should be mounted.

 

What's your concern, that the battery will go flying in an accident? I just don't see it.

Here's what I feel:
In order for the battery to come out of the well and go flying, it would have to go up (almost 18" to clear the lip). In any (other than a rollover/flipping/etc.) accident, the inertia of the battery is going to want to go laterally (front/rear/side to side), not up. It's down low IN a box, so it's contained and can't go anywhere without busting through the enclosure. Worst case, it busts through the bottom and is laying on the road?

Again, this is what GM did with the C6. This picture is of a C6 battery well. Note that it's the same fiberglass box (shaped slightly different) with only a metal bracket on the edge. The battery itself isn't mounted "to the frame".


As I look at this, I'm actually start to wonder if I could find a wrecked C6, cut that compartment out and graft it into my C5.

But perhaps I'm missing something?

 

Better find more pics of the C6 battery mounting. Again, ask any experienced car builder where to mount a battery. Its your car. If your proud of your work, and you are happy with it, then that is all that matters. This forum is about offering people advice and that is what I did. You will NEVER prove to me that the way you mounted it is a better solution than tying it into the frame.

 

I would be foolish to say that my way is "better" than tying it to the frame. My position is that it's probably not "necessary". Big difference.

With that said, I'm not in disagreement with you and I may yet add a brace off the frame. I need to go find a C6 Z06 to crawl under and see what their battery well looks like as that would give more insight.

 

Here, let me help you. This is out of the GM parts catalog. #10 in the pic is the metal bracket that bolts it to the frame. It should not be that hard to add a brace to your set up because the frame is right along side of your battery.

 

That's very helpful, thank you.

 

This is a good thread.

 

I was browsing through posts and came across this, so I figured I'd give an update.

It's been over a year since I did this relocation and it's been quite nice as I can certainly tell that the car is better balanced. I have yet to get around to actually making a mount as a few months after I did this mod, I picked up a 79 C3 and that's been taking all of my time. Oh well, one of these days....

 

Do you have any pics of the alternator wire connection point? I'm pretty much copied your set up, very easy so far. I purchased a battery bracket that fits in the same compartment but used a D51 optima instead.