Trunk Mounted Battery Questions

ERA 778 · #1 (**permalink**) 11-18-2009, 05:25 PM

Hey guys!
I'm in the middle of building #778 and so far it's been great. I opted to mount the body myself and also for the trunk mounted battery in the all-aluminum trunk. I'm working on the wiring for the battery and some speakers and I've run into some questions.

The main issue is that I'm finding it hard to believe that I will be able to get a Group 34 Optima battery into this space and, most importantly, attach the battery cables to it. Have any of you guys done this? Will the battery posts clear the upper lip on the battery compartment cover? How did you ever get the battery cables to bend enough to position them correctly.

Photos and explanations would be greatly appreciated. I'm even thinking of going with the GM side terminal battery to make the job easier. Any ideas?

Thanks!

patrickt · #2 (**permalink**) 11-18-2009, 06:01 PM

patrickt · #3 (**permalink**) 11-18-2009, 06:16 PM

There's also a supplement to the manual in the owner's section that has extensive hand drawings, links, etc. on the rear mount battery installation. Last time I posted a direct link in there Bob P. politely kicked my a$$, so if you can't find it, PM me and I'll send you the direct link that way.

ERA Chas · #4 (**permalink**) 11-18-2009, 06:35 PM

Mine is an early car so there's no closure panel. The side terminals are for main power and I use the top terms for a pigtail for the Battery Tender.

Kill switch is directly behind the battery on the bulkhead. Use zero cable. Hate the battery holder and will change it to Optima aluminum cage when I next drop the tank.

strictlypersonl · #5 (**permalink**) 11-19-2009, 05:58 AM

The somewhat crude instructions are available here.

Mooch · #6 (**permalink**) 11-19-2009, 06:55 AM

Has anybody used the Summit battery hold down #SUM-430015? Any better alternative - Billet Specialties, etc?

ERA 778 · #7 (**permalink**) 11-19-2009, 06:18 PM

Thanks, everyone.

I know the battery will fit, thanks to all these replies, but it sure will be tight!

I also was checking for mounting speakers in the rear bulkhead and it looks like I will need to move the battery a couple of inches toward the center to provide an adequate space on each end for 5.25 inch speakers.

Gunner · #8 (**permalink**) 11-19-2009, 06:41 PM

Quote:

Originally Posted by Mooch

Has anybody used the Summit battery hold down #SUM-430015? Any better alternative - Billet Specialties, etc?

For my Mustang's trunk-mounted batt, I found a beautiful billet holder from (IIRC) a marine supply. I drilled the top plate to hold the cutoff switch; with an Optima battery there was just room for the switch body and heavy gauge wiring between the plate and battery top.

I'd have to dig to find the exact source etc. Point is, check the marine suppliers for some awfully nice and not always overpriced stuff.

xracerbob · #9 (**permalink**) 11-20-2009, 10:09 AM

I used a Braille battery in mine. Very small and light. I gave the mounting bracket to Doug and he mounted it for me in the trunk. Lots of room. After having it for a year or so, it works great. I think the one I have is the 2015.

http://www.braillebattery.com/index.php/

patrickt · #10 (**permalink**) 11-20-2009, 01:21 PM

Quote:

Originally Posted by xracerbob

I used a Braille battery in mine. ]

I guess you get used to the "battery acid on the fingertips" thing, huh?

fkemmerer · #11 (**permalink**) 11-22-2009, 07:57 AM

Here's a picture of the setup that ERA did for my cobra. You can download a higher resolution version from my gallery:

We did a remote battery cutoff switch which is mounted to the lower right of the battery itself. Hope this helps you. My setup uses both the top and side terminals on the optima battery (the side terminals are used to power the EFI computer even when the battery cutoff has disconnected everything else.

- Fred

CCX 33239 · #12 (**permalink**) 11-22-2009, 03:13 PM

ERA 778,
I got my speakers to work real well mounted along the outside of the rocker panel on each side!

flaflier · #13 (**permalink**) 10-31-2011, 06:18 AM

I am looking at redoing my rear-mounted battery. It presently has a battery box/hold down adapted to fit in the trunk, which makes for a very tight and not very visually appealing installation. I have reviewed the somewhat "crude instructions" from ERA, but would like feedback on 2 other options that also look acceptable to me. Has anyone used either of the 2 in the pictures?
I am going with 1 of the 3 (standard, billet, or ERA), so any positives / negatives would be appreciated.

Jim

Standard

Billet

ERA 778 · #14 (**permalink**) 10-31-2011, 06:47 AM

I ended up using the ERA mounting hardware, but moved it toward the center about 1.5 inches to clear my speakers. Works great with Optima battery. Also added a kill switch in the panel next to the battery.

You'll have a tough time accessing the hold-downs on either of the designs you're looking at. The ERA approach uses the chassis crossmember and a small piece of angle on top of the battery. Works well enough and you can get to it easily.