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Opeler
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...No leaks of any type is a given
...as is a secure and substatial mount capable of dealing with drastic deceleration
...I evision a sealed box with the cables passing through and fixed to the wall of the box, but I'm not sure about the heat buildup. Marine boxes that I've found so far are cheap plastic and NOT sealed, are there better options?
 

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Personally I would fabricate a solid box, say 1/4" aluminum sides and top with a steel base all bolted together with MANY grade 8 bolts (UNC10-28) and weld the base plate in place. This will pretty much give you an explosion proof enclosure. It shouldn't weigh more than 10-15lbs.

Place a terminal strip on the inside of this box and use U-connectors (not loops) to attach all connections. If you were in one hell of an accident that tore the welds securing the battery 'box' the terminals would let loose at this terminal strip inside the box, leaving no chance for arcing (sparks). If you want some extra protection in case your worried your accident will be severe enough to break the welds securing the 'box' and your not hip on this becoming a missle on the inside of your car and you'd like some extra grounding protection. Place a grade 8 UNC1/2-13 bolt on the box (use a thru hole and a grade 8 nut) and another one in a very secure location (maybe make some sandwich plates) near the box. Get yourself a piece of 10,000 pound cable (it's not as thick as you'd think) with a loop on each end long enough to reach each of these bolts. This should add some grounding protection and keep the 'box' from going too far if it should seperate from the car.

Now to keep the battery secure in the box I would recommend expanding foam. NOT the home insulation type, but a mix (part A, part B) and pour. There are MANY manufacturers and grades out there that will fit this application very well. It should handle an impact very well and if the battery should explode the foam will absorb that as well. It's inexpensive will protect and secure the entire battery and when you need to replace the battery you just cut the foam up and pull the battery out. You can probably get creative and place some handles of some sort so when the foam hardens around the battery and handles you can pull the whole thing straight out of the box. If you go the foam route be sure it's a non-conductive grade and when it is expanded it covers the top of the battery as well. Usually you let it over fill and cut what expands out over the top so it fits perfectly in the box.

I know, your thinking HOLY CRAP that would be overkill. Of course if you were on the highway and went head-on into a Mac truck bounced into the other lane where another Mac truck was going the opposite direction and smashed you again. This battery box would survice nicely, with a very low chance of explosion related to spark/arcing. Of course if your in any kind of accident that severe, you'd care less about gas fumes sparks or explosions. It is a VERY safe route to go, and more so if there is any chance of racing this car. :D

One last thing. If your thinking of using wood anywhere on whatever direction you decide to go be VERY aware if any battery acid gets on wood it basically disintegrates.
 

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wood and wax

If you can find wax impregnated wood it will work fine in a battery environment. That is how the 120+ 1800+# 2 volt battery cells in the Navy's submarine fleet are actually mounted in place, and they leak gallons more acid then your car battery will ever have.

One more idea, from the guy who doesn't drive an GT, is as follows:

-Remove the curtain, top shelf, and shelf the tire sits on from the back of your GT. (It really isn't that hard, and you may find yourself not wanting to put it back in.)
-Duplicate both the top and the bottom shelfs in either steel or aluminum. Even with 1/4" aluminum you will probably loose some weight over the particle board, but 1/8 inch should work fine.
-Properly attach a good battery holder to the bottom plate. If you need more height recess it into the bottom panel and box it in as appropriate. I recommend one of the steel or aluminum battery holders from Jegs or Summit, but I have a sheet brake and would bend up my own. If you get one of these you can just drill all the holes in your bottom plate to match the ones in the bottom of the battery box.
-Reattach the upholestry to the new panels, or take the opportunity to spend $3 for a yard of new black vinyl for the top shelf and don't worry about the bottom one.
-Make a new aluminum or steel panel to replace the curtain in the car. Not only will it look nicer, it should make your new "trunk" meet the requirements for NHRA and protect you in a crash. Cover it with the rest of that yard of vinyl and you're set.

Just one more idea.
Stephen
 

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Opel Junkie
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113 Posts
Rear Mounted Battery Box

hey all...

i'm thinking about mounting my battery in the back of the car, somewhere in the spare tire box. has anyone done this mod? if so, how did it work out? how big of a cable should i use?

thanks for any input.

mike
 

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Here's a whole thread dedicated to the topic, which I merged with your question. John Warga (aka "ftl") here in Calgary has also relocated his GT's battery to the luggage area. I believe he is in Phoenix AZ this week, so he won't be able to show off his handiwork. But I happen to have a photo of the work in progress, so here it is
 

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And here is a photo of Otto's' box, locating it in the spare tire area.

By the way, I believe that a #1 gauge wire is what John used, but I suspect that was because he happened to have thirty feet of the stuff spare from some big computer networking project, and it was a fair bit if overkill. I believe that #2, or even #4 would probably be fine.

JM2CW
 

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1450 Seeker...
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Nothing like diggin up ancient threads!

I am going to be relocating the battery to the rear "seat" area, and I was wondering what route everyone else chose to get the cable from front to rear. I was looking at two options

1) Through the firewall then under the carpet back to the battery

2) Under the car (Probably alongside the brake lines), drill a hole and then up to the battery

What path has everyone else taken?
 

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70's Opeler, back 4 more!
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The last one I did was through the firewall, routed on the inside of the car. I figured that way it was protected.

I've also wondered lately about installing a gel battery since you can lay them on their side, which could then be put in several places.

I looked at the gel's and boy! are they pricey.
 

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Kieth - what is the electrical wiring to the right of the new battery box? is it the stereo or did he also relocate the fuse box? Do you have any pictures of the finished product? I also wonder what that area looks like from underneath. That would have to be about the best place to put the battery for balance as well as safety, but maybe on the other side if it doesn't interfere with the exhaust. Of course, if one is running a dual exhaust...

Allen
 

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70's Opeler, back 4 more!
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I assumed it was the fuse box relocated.

But I was wonding if the rear vent windows were electric? and are those lights next to the "trunk" door, next the speakers, close to the window?
 

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what is the electrical wiring to the right of the new battery box? is it the stereo or did he also relocate the fuse box?
He re-wired the entire car. The fuse box was replaced with a rack of circuit breakers located in the engine compartment just above the brake rod. The relays and such in the rear area are for various other devices, such as the alarm system.

But I was wondering if the rear vent windows were electric? and are those lights next to the "trunk" door, next the speakers, close to the window?
The rear vent windows ARE electric, as are the door locks, and both are remote controlled by the alarm fob. The small round items on the cargo divider are horn tweeters (high frequency speakers). And he installed a spare set of the Mazda RX-7 power mirrors that I gave him. But he hasn't (when I last talked to him a month or so ago) installed power windows.

I will ask John to share some photos of the finished product. The breaker rack is amazing, as he designed it on a rotating rod, so that in the normal position, the wires are underneath. Then he rotates the rod to get easier access. Very clean.
 

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Opeler
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Keith called me and asked me to post some more info on what I did for a rear battery installation, so here it is.

Here is the battery and the box I made for it. The battery is a 58V series, that seems to be used in a lot of Fords, so it is relativly common (I bought it at WalMart). The key with this battery is that is is one inch shorter than any other common automotive battery. That reduced how much the battery box must hang down under the car.
 

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Opeler
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I forgot to mention that the box is welded up from a peice of 18 gauage (or so) steel that I was using for body repairs.

The next picture shows the box and the hole I cut for it in floor behind the driver's seat before I installed it. You can also see some of the rust fixes that needed to be done.

Why mount it there?

Firstly the exhaust and muffler uses up much of the under-body space on the other side. There was very little in the way on this side. The hole is placed just in front of the sway bar (there is about 3/4 inch clearance from teh finished box to the sway bar. The brake line goes just to beside the box, in fact the bracket that holds one end of the flex brake line to the diffy had to be removed from the body and welded on to the battery box later.

The emergency brake and fuel lines go around the other side of the battery box.

The battery box has a hole in the bottom of it as a drain for any spilled acid or water, and although they have not been installed yet here (so you can't see them), air vent holes on the front and back that hang below the body to allow the battery compartment to be vented to the outside. The drain hole will also drain any water that may come in via the vents.
 

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Opeler
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Once installed, the top of the battery box was about 1/2 inch below the bottom of the plywood that would cover the "rear-seat" area. This was to allow for the installation of weatherstripping along the upper edge to seal against the plywood to cover the top of the box.

I have designed the rear cover to be hinged, so I can easily access the battery and the storage areas that are around it. I have covered the bottom side of the oplywood with vynl so any fumes from the battery box will not be absorbed into the wood.

As pointed out in some of the notes above, I also installed a bunch of wiring to one side of the battery. that was part of my complete re-wiring of the car. hidden back there is the turn signal flashed, relays to run the turn signals, an alarm system with some associated relays, fuel pump relay and some terminal strips that keep the wiring neat. The wiring for the rear speakers seen in the pictures Keith posted also go through that area. I just hate working on wiring up under the dash of any car, so I have moved much of the wiring to places I find a lot earier to get to.

The main battery wire is a 1 guage wire that runs from the battery box, under the car to the starter. I ran the cable through a peice of clear hose as extra protection for it. You do not need that wire shorting out.

Since the wire from the battery box is longer than the original, a thicker wire is a good idea. The original wire is about 40" long and is made up from wire that is between AWG 5 and 6 in size. It has a total resistance of about 0.0012 ohms.

My new wire was about 70" long, and was made from 1 guage wire. This had a resistance of about 0.00065 ohm, or about half of the original wire. Basically 1 guage wire is a bit of overkill, but as Keith noted, I had it around. I would reccomend 2 or 3 guage wire if you were out buying it.

Once welded in place, the battery box does not stick down any lower than the existing body (although it is close), so it should be relatively immune from damage (I hope).

Here is a picture of the battery box hole from the bottom.
 

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Opeler
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Just complete the pictures of this project, here is a picture of my new rear shelf area (on top of the gas tank) with the mini-spare as compared to the original.

My shelf sticks further back than the orignal, and provides more storage to the side. I also elected to have it shorter in the front to made use of the area where the upper shock mounts are.
 

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Opeler
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And finally, the last post, here is the completed rear area with the access door open. you saw it with the door closed on a picture of mine that Keith posted earlier.
 

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Weight Distribution

Has anyone who's relocated the battery to the rear done a before and after measurement of the weight distribution on all 4 wheels; if so, I'd be curious to know what the change in the weight distribution was.
 

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Has anyone who's relocated the battery to the rear done a before and after measurement of the weight distribution on all 4 wheels; if so, I'd be curious to know what the change in the weight distribution was.
Batteries weigh somewhere from 40-60 pounds depending on there size. I moved mine from the very nose to under the package shelf, and went to a 38 pound optima I'm sure it helped a lot. Plus changing the heavy stock radiator to a aluminum, I know I shaved 60-70 pounds off the nose easy. And it looks better too, win win.

Pat
 
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