Trunk-Mounted battery Question

[Scottie-GNZ]

For those of you with a trunk-mounted battery, what gauge cables are you using and how did you do the ground?

[Guest Anonymous]

I'm getting ready to do the same thing. Summit's got a battery relocating kit that looks like it's got everything needed. Have you decided where you are going to mount yours?

[Guest zfan]

Hey guys I used a Taylor Battery relocate kit.

I got the mounts with aluminum box and breather line to vent battery fumes outside.

 

I mounted mine over the passenger side rear compartment, close to rear wheels for added weight over there.

 

I used 1 gauge wires and grounded to frame.

Hope that helps.

 

Mike

[Guest Frank280z]

01 gauge welding cable

[Mike kZ]

I used 00 cable, the ground is bolted to the frame

[240Z Turbo]

Go to the local welding supply and buy 0 or 1G cable. Buy the smash on ends and you are ready to go. I ran both ground and power up to the starter from the battery. It is not ideal to just ground the bat to the chasis.

[Owen]

There was a discussion a while ago on which boxes really track legal. So you might want to look into that Scottie. Someone told me my blue Moroso box isn't track legal cuz it's plastic...

 

Owen

[Scottie-GNZ]

Owen,

 

that someone is wrong (as usual, not having the facts). MOF, Moroso is the only NHRA-certified plastic box.

 

Crap, it is always something with NHRA. A cutoff switch is also mandatory with a relocated battery. The following are excerpts from the NHRA rules FAQ:

 

I have a street car that I occasionally run at the strip. I've relocated the battery to the rear. What else do I need?

Any car with a relocated battery must be equipped with a master electrical cutoff, capable of stopping all electrical functions including ignition (must shut the engine off, as well as fuel pumps, etc.). The switch must be located on the rear of the vehicle, with the "off" position clearly marked. If the switch is of a "push / pull" type, then "push" must be the motion that shuts off the switch, and plastic or "keyed" typed switches are prohibited. Also, the battery must be completely sealed from the driver and/or driver compartment. This means a metal bulkhead must separate the trunk from the driver compartment, or the battery must be located in a sealed, metal box constructed of minimum .024 inch steel or .032 inch aluminum, or in an NHRA accepted plastic box. In cars with a conventional trunk, metal can simply be installed behind the rear seat and under the package tray to effectively seal the battery off from the driver. In a hatchback type vehicle the battery box is usually the easiest solution, since the alternative is to fabricate a bulkhead which seals to the hatch when closed. At present, Moroso is the only company which offers an NHRA accepted plastic battery box, part number 74050.

 

But I drive on the street. I don't want a big cut off switch hanging on the back.

This solution takes a little work, but it solves the problem. Install the master cutoff inside the vehicle, positioned "sideways" so that the toggle moves forward and back. Drill a hole in the toggle handle, and attach a steel rod that will run out the back of the car, through a hole drilled completely through one tail light assembly. Have a spare tail light assembly on hand, so when you come home from the drags, you remove the rod and put the cherry tail light back in for street cruising. Next time you plan on going to the drag strip, swap lights and reinstall the rod. Since the drilled light is for the strip only, you can also have it marked "PUSH OFF" in big letters so the Tech Inspectors will think you're cool.

[DAW]

I put mine in the spare wheel well and grounded to the frame (and use a ground strap up front, engine block to frame), but at times I think that I should run a ground cable direct to the block.

 

One of the best setups I've seen is the type I have in my Starion. I bought it from TEP and it's a battery box steel frame incorporated into the rear strut brace...it's really well made and a great design. I put a marine plastic box lid over the orbital battery and secured it hold-downs and stainless steel acorn nuts. I don't know if it's available for the Zcar or not but it's "two birds with one stone"...(whatever). If not available...design engineers?? DAW

[Dave]

Here are some cable specifications and and tips for trunk mounting the battery in a Z. Click Here There is more info here than what you need but it gives you a idea how how much power is lost through the cable. MAD enterprises sell a remote solenoid kit for a trunk mounted battery. Click Here I bought this kit and used it in my Z. I have my remote solenoid back by the battery in the back of the car. I used a 8Ga wire to power the rest of the accessories. Here is a scan of the directions that came with the MAD kit. Click Here

[blueovalz]

I'm using 00 welding cable for the long run up to the starter solenoid. Then I used 6 awg for the ground being it was only a few inches long going to the battery box frame which was a metal encloser welded to the chassis.

[Owen]

Scottie,

Thanks for the info. Your car's lookin good, by the way! Now are those rules for a certain class or a certain trap speed?

Owen

[Scottie-GNZ]

Owen,

 

those are NHRA rules out of the "General Rules" section so I assume it applies to any car.

 

Thanks all for the input.

[pparaska]

I used 2 gage battery cable (from the Taylor kit) for the positive, and 2 gage welding cable for the ground. I ran the battery cable through a cut-off switch (the type I used is not NHRA legal), then to a Ford type solenoid. I ran the ground cable to the bellhousing/block bolt right near the starter. I haven't had a problem with starting the car yet. I would go with 0 or 00 gage next time, I guess. But 0 gage has 2/3 the resistance of 2 gage, not a huge difference.

 

I put my battery up on the package shelf, right behind the passenger seat. I wanted it more near the center of the car, for polar moment of inertia reasons. That's kind of a dead space there anyway, so it worked out well. I used the Summit AL sealed box.