So I ditched the stock battery, and ran two 4 guage positve and a 4 guage negative to the trunk, about 12 feet in length to a genesis G16EP which is identical to a dynabatt. The car will start, but after driving it around for a bit and shutting it off it wont restart. The voltage is 12.6 with the low beams on and 12.2 with the high beams consistant.

Problem is, while a buddy and I were doing the swap. We managed to swap the positive and negative terminals on the battery long enough that SMOKE started to come out of the alternator.

We dont know if our issue lies there or if the rediculously long length of ground wire is insufficient. I think the battery is fine. My buddy thinks its the battery.

I ran a dynabatt in my 98 TA up front without issues.

We cant tell if the alternator isnt charging adequately now. We did disconnect a terminal after starting the car to see if it was the alternator after the terminal mismatch, and it kept on running.

Is the length of cable too much for the dynbatt? It only has 280 cca.

 

What did you connect the wires to in the front? I handmade a set of connectors that you bolt the orginal battery cables to the connector and the 2 ga wire to the opposite side and run the wires back.

Alternator is probably toasted.
Phil

 

At only 12.2 VDC, it sounds like the alt is toast. The battery should show 13.2VDC, and close to/at 14VDC when the engine is running. If you can start the car, check from the alt +, to ground. Should show over 14, especially if the battery is low. If it shows only batt, then the alt is history...

As for the cables... The ground side of a system has to handle the same loads as the + side..
To run 2-#4's+ and 1 #4-, is not the best way to get the system to function correctly.
We use 1/0 welding cable on both sides of the system, and #6 for the alt charge wire, directly to the battery.

 

we took off the alternator today and tested on test bench at a kragens, it checked out fine. The battery is also fine, this has to be a case of insufficient ground. We are using two 4 guage positive wires, one to the starter and the other to the fuse box. There was a 4 guage ground wire attached to the block and a smaller 8 guage wire attached to the frame that piggy backed that ground, we didnt reattach that ground wire and that may be where the problem is.

We are going to reattach that and run another 4 guage wire directly to the frame rails near the IRS, hopefully this solves the problem. There is no way Im gonna be able to accomodate 3 12 ft strands of 2 guage wire though my car, it certainly wont fit in the side trim.

 

Most people run the cable through the right side rocker panel just outside the frame rail, there is lots for room in there for the cable.

 

Wow, that is a tiny battery for a car. That think is only rated at like 16-18Ah. You will need really good cables because with a battery that small you can't afford to loose anything between the battery and starter.

 

It may be the battery just doesn't have enough power to start the car hot. I have an old pickup with headers and when it gets hot sometimes it won't start. I've never had this problem with an LS1, but maybe with the small battery heat becomes an issue.

Just a thought.

 

thanks for the suggestions, but I think its a ground issue.

As for the battery not having enough power to start a hot motor, we connected a 800 CCA optima redtop and it wouldnt start the hot motor either.

Inadequate cable? 0 or 2 gauge was recommended, but only one strand that is split at the front of the car to the starter and fuse box into two 4 guage wires respectively. Well Im running not ONE but TWO strands of 4 gauge directly from the starter and the fuse box all the way back to the OE terminal positve terminal connector. So thats not the issue here. Ive come across numerous battery relocation "how to's" on the internet, and the majority of them 4 gauge was used.

This has to be a case of insufficient ground, I need to ground the battery to the frame rails near its mounting location. 12 ft of 4 guage wire to the block is obviously not enough. As a matter of fact, initially we couldnt even start it cold with the dynabatt as we had the ground running to a bolt in the door sill. We ditched that and ran it to the block and now it will start cold. Were gonna add another ground today. i bet this is the problem.

 

I've trunk mounted batteries on '55-56-57 Chevy hotrods with high compression ratio crate motors. They didn't have all of the electronics that a late model Corvette has. I've always used 00 gauge cable intended for the purpose. It's available through stereo shops (not 00 welding cable with thin rubber sheath which is effected by heat and oil).
I've used either the frame for the ground or run another full length of the same gauge cable to one of the mounting bolts on the starter motor. That's always a fail safe manner to complete the circuit. If you have questions about trunk mounted batteries, check with Mark Harmon of M.A.D. ENTERPRISES or madelectrical.com

 

get errrrr done! drycell working like a champ!

--------------------------------------------------------------------------------

So it was indeed insufficient ground, i attached another ground to an existing ground post on the DS framerail near the IRS and it starts everytime.

The battery and bracket together weigh right about 14 lbs, and 24 ft or so of 4 gauge wire another 4-5 lbs. Looks pretty trick too. Should be a little closer to 50/50 now. Got 3040 on a scale with 6-7 gallons of fuel, with 20 lbs increments so it could be less.

For anyone doing this, youre going to need more than the stock ground going to the block, youll need to ground it to the chassis in the rear as well.

heres a pic, I have another in my gallery.

http://www.z06vette.com/gallery/show...cat=500&page=1

 

I'm interested in the issue because I intend to relocate the battery next week
But this link does not work for me apparently