View Full Version : Battery in the trunk

10-11-2011, 03:54 AM
Or - in my case - battery in the hatch.

I know many have done this mod and I am thinking to do it so I can move my AFM directly on the compressor intake and also gain some engine bay space.

Do most rely on the frame of the car for the negative lead or run two cables? What is the cable routing and ingress egress points?

Where do most put the battery? Any pics?

10-11-2011, 04:49 AM
I have this documented in my project thread. I am using one of the shock tower nuts for my battery ground.

Sent from my iPhail

10-11-2011, 05:45 AM


10-11-2011, 03:32 PM
I did a mix of Cap's and another one.

People say for weight balance you should put the battery in the passenger rear corner of the cargo area. I have mine in the drivers side (as I didn't account for this in the bulk wire purchase). I will be having a 10" sub and box on the passenger side now so that should balance out my ass weight.

I ran the B+ cable through the fender well (wrapped in split loom to prevent any chaffing/damage). From there its running inside the cabin in the drivers wire loom up to the front wheel well. I'm using an existing grommet and ran the wire through there (behind the splash guard) into the engine bay. It's then split into a couple wires to feed the alt, starter and fuse box.

Here's the link to the wire running

Pics below are of it completed.

New home: left rear corner of cargo area (drivers side)

http://www.ourlewisfamily.net/content/Jasmine/normal_battery_box.JPG (http://www.ourlewisfamily.net/content/Jasmine/battery_box.JPG)

http://www.ourlewisfamily.net/content/Jasmine/normal_battery_box2.JPG (http://www.ourlewisfamily.net/content/Jasmine/battery_box2.JPG)

http://www.ourlewisfamily.net/content/Jasmine/normal_battery_box3.JPG (http://www.ourlewisfamily.net/content/Jasmine/battery_box3.JPG)

200a fuse located just behind battery box.

http://www.ourlewisfamily.net/content/Jasmine/normal_fuse.JPG (http://www.ourlewisfamily.net/content/Jasmine/fuse.JPG)

The fuse is secured to the body with simple sheet metal screws, and the battery box obviously by that yellow & black strap. There are 2 strap mounts/tiedowns that are underneath the carpet, secured to the body with sheet metal screws as well. I then cut slits in the carpet, and ran the strap through these slits, and under the tiedowns.

HEre's where I mounted the power block in the engine bay. To prevent ground-outs (as this is the positive 12v feed), I used one of the old mount rubber flaps between the body & the plastic housing of the block. I then wrapped the screw heads & upper threads in electrical tape, and covered the tops of screws with electrical tape. Yes it may be a little overkill, but I didn't want any risk of ground-outs in the engine bay killing everything.

http://www.ourlewisfamily.net/content/Jasmine/normal_power_distro.JPG (http://www.ourlewisfamily.net/content/Jasmine/power_distro.JPG)

http://www.ourlewisfamily.net/content/Jasmine/normal_power_distro2.JPG (http://www.ourlewisfamily.net/content/Jasmine/power_distro2.JPG)

I have dual 4g feeds running out of that block that will goto the Fuse block & to the starter. I have a third connection in the event I need another feed from somewhere (yes.. the 4g lines are currently still connected, I need to cut & terminate the ends after the engine is in the bay).

Here's where I ran the power wire through the fender into the cabin.

http://www.ourlewisfamily.net/content/Jasmine/normal_power_wire.JPG (http://www.ourlewisfamily.net/content/Jasmine/power_wire.JPG)

10-11-2011, 04:40 PM
Just make sure you have a gel battery (Optima etc) so you don't gas yourself as its hard to vent the hatch appropriately.

10-11-2011, 09:06 PM
I don't like the battery in the trunk.

Less power getting to electricals [at least some of the no start problems are from this, not bad starter relay wiring], routing battery cable all along the car, battery in the way in the trunk, PITA to jump, drilling holes in the trunk, ect.

I've got an Oddesy gel battery that's ~ 8 x 4", never had a problem starting, fits fine in the engine bay, even with an AFM and I don't have all those other hassles.

10-12-2011, 12:13 AM
An 8" X 4" battery and it is enough? With that I could prolly get the AFM in that space next to it. I'll have to look into that one. I don't have any bigtime stereo and don't plan on it - maybe 100W max.

The "old" reason to move the battery to the trunk was handling - all that weight over the driver side front wheel would cause it to "dive".

I myself have two cables of very fine stranded wire that are at least 000 gauge - and maybe even 0000 gauge - with heavy insulation. These came off a Kohler gas generator that was used to service semi-trucks on the highway. They are 25' long!

I was thinking to cut these to length and use two - I don't like the idea of using the body as a ground for the starter - I would rather have a cable bolted to the block.

Yes it is true - having a battery in the hatch is an inconvenience - but with that battery tucked in the way BurnyD Jr has it - it really looks like it is well out of the way of any space you would use.

10-12-2011, 02:55 AM
I had them battery in them trunk of my old 90 gt and never had any problems

10-12-2011, 03:52 AM
it depends though.Some have had bunch of electrical problems when relocating others have good luck, I deff wanted to do the relocate but im still debating on it,


10-13-2011, 04:17 AM
I have my red top optima in the cargo area as well. I have it on the passenger side and its grounded to one of the seat belt bolts. I have a 10" sealed sub box on the drivers side and and and I ran the 1 gauge cable through the frame/body like in captain's thread and it goes directly to the + post on the starter.

10-13-2011, 04:42 AM
those little batteries are great, I plan on getting one and moving the battery to where the stock airbox is and then having a straight intake. or you can keep it in the stock spot and make a straighter intake than stock. A few of my friends have them running RX7's, 240SX's and R32 Skyline GTR's.

10-15-2011, 03:22 AM
Before I did a hatch relocate I found a way to mount the stock battery where the air box was and then I did a straight intake. There is no need to get one of those small battery's to do a straight intake.

Hipster Lawrence
10-15-2011, 02:40 PM
Done right you will have no problems at all. Lots of cars have remote batteries from the factory. Almost all euro cars do. There is no reason to fuse it if you do it right.

The battery needs to be sealed like an AGM battery or be a standard wet cell with vent tubes you can run outside the car. IMO the best value in a small battery is the miata battery it weighs about 15 pounds it's tiny and has vent tubes. Costs about $70.

10-15-2011, 06:41 PM
no reason to fuse it? There's no reason NOT to fuse it.

10-15-2011, 07:08 PM
I dunno - I am leaning towards pulling out the rear seat bottom and putting the batt there - the rear seats are tits on a bull anyway.

This way I could just leave the seat backs down all the time and run a two-seater. The cables would be shorter and the batt would be out of sight and out of mind.

For jumping I could bring out some terms in the engine bay.

All the pics of engine bays with he small batt up front in the usual place AND the direct connection of the AFM to the compressor inlet look pretty crowded and tangled to me.

Anyway you shake it - the sealed gel-cell batt is a must.

The downside of this approach is obvious - no rear seat anymore for the odd time you want to haul passengers.

10-16-2011, 02:10 AM
I'll try to post a pic of how mine is set up.
There's no need to put the battery in the stock location in the engine bay, especially with one this small.
You can fab up a mount [which I haven't done yet] and put it almost anywhere in that area.

10-16-2011, 08:15 PM
I'll try to post a pic of how mine is set up.
There's no need to put the battery in the stock location in the engine bay, especially with one this small.
You can fab up a mount [which I haven't done yet] and put it almost anywhere in that area.

Thanks man - I look forward to seeing that - the ideas for alternate locations of the battery.

I have access to a shear/brake/slip roll at work - so I can fab whatever mount is needed for any of us - so long as it is sheet metal and not some really heavy gauge stuff.

10-17-2011, 03:25 PM
Honestly, you can mount this upside down if you wanted to, or lay it flat so the terminals are on the side of the battery.
Disgregard the mess, I have no time to work on this thing and it's come a looooong way.
I haven't made a mount yet, I'm not exactly sure where everything is going.
In my 92 I had a Optima redtop with an aluminum mount sitting above the trans mount. This thing is even more versatile.
I haven't had any problems starting, even down to ~ 40*.
I don't run this in the winter, so I don't know how well it would do in 20*, but it's had no problems starting it while I had no CSI with the RC electronics, it took like 10 - 15 sec to get it started.

I got it at Summit, here's the link. You'll also need the terminals they list.


Hipster Lawrence
10-17-2011, 06:41 PM
no reason to fuse it? There's no reason NOT to fuse it.

Ever seen a fused starter cable on ANY car from the factory? It's just asking for problems.

Say the starter draws 200a average. That would mean you'd want a 400a fuse. I think if the cable dead shorted the car would burn up before the fuse would blow.