Fuses and Battery location(s)

[ChrisMiami]

I keep mulling over the battery placement. Although I wouldn’t put it unshielded next to the gas tank, I do think that locating it in the rear (probably in the custom “trunk” space people make) is the best place for it. Clean and easily accessible.

I’m also thinking that an ideal place for the fuse box would be right where the flux capacitor normally goes: the slanted plate at the rear of the trans tunnel. Either inside it or just right on top with a cover over it. Talk about an easy spot to swap a fuse!

I’m also thinking there must be some way to collect and route wires without the place looking like a rat’s nest. Could mount a block of plugs at strategic places around the frame with wires between them running inside the rails like conduit. Plug the battery hot side into a plug nearby and plug the starter into a socket right near it. No 20-foot hydra —I mean, harness, to deal with.

What do you guys do for ground? I’m assuming to use the frame you’d have to remove the powder coat?

[Alan_C]

For trunk mounting, many of us here used the aluminum battery box made by FFMetal. When making ground connections to the chassis, yes the powder coating must be removed so you get the best connection from cable to frame. I would recommend you increase the size of the battery cables when mounting in the trunk. The 4 gauge cable FFR supplies is barely adequate IMO, a 2 gauge would be better for both ground and positive side. Another ground cable is then installed from the block to the frame in the front. When choosing a battery for use in the trunk, a AGM style is preferred as they do not outgas hydrogen when charging and do not have a liquid electrolyte that can cause corrosion should you have a spill. I like the Odyssey AGM batteries myself as they are a bit smaller and lighter but are not cheap either. Fuses for the starter should be near the battery, others as convenient.
https://www.ffmetal.com/index.html#bb

[edwardb]

We are talking about a Coupe here, right? The factory battery location is in the front. Behind the steering rack and well in front of the engine. Pictured below. The location works fine. The power runs are short and it's reasonably accessible if necessary. The main battery ground I installed is visible. There are a couple more for the harness in the cockpit. The advantage of the one-piece steel chassis is that you can get a solid ground anywhere you have a clean and tight connection. It's a common mod for the Roadster to move the battery from the stock rear location to the front. Or use an aftermarket mod to put under the trunk. But not necessary with the Coupe.

No reason for the wiring to be a bird's nest. Completely up to the builder. My Coupe wiring pictured below. The loose headlight switch and start button go into the dash when installed. The two connectors on the LH side go into the instrument cluster. The stock location for the fuse panel is in the underside of the driver's footbox. It's not particularly difficult to change fuses. I've only had to change two in four seasons of driving. Both self-inflicted. The issue with moving it elsewhere, if you use the kit Ron Francis harness, is the harness legs are designed for an upfront location. Moving if any distance is going to make them too short and result in a lot of rework. For questionable gain. Builder's choice of course. The runs are all relatively short with the exception of the rear harness leg (lights, fuel pump, fuel sender, speed sensor, etc.) which routes neatly through the transmission tunnel and along frame rails to the back. Putting wires inside frame rails has been discussed on here before and generally not considered a great idea.

https://thefactoryfiveforum.com/attachment.php?attachmentid=97587&d=1542472755

https://thefactoryfiveforum.com/attachment.php?attachmentid=101822&d=1549503433

[ChrisMiami]

Sometimes I tend to want to reinvent the wheel. I’m sure the closer I get to actually having things in my hands that will die down. I do think the rear reloc is a plan (for me) and I’ve always wanted the AGM battery - thanks for the tip on that and the larger cables.

Now you mention it, fuses are a very seldom changed item. Still, I do think a more conveniently-accessed location should be found for them. I want to make maintenance super easy. Saab had most of them under the hood in front of the driver side foorbox, and it was a blessing when swapping relays.

I had another think on putting wires into the frame. I agree - bad idea for many reasons.

[David Williamson]

Your car your choice but. The front location has advantages, short cables, easy access and it helps balance the chassis closer to 50/50 weight distribution because the engine is so far back in the frame there is more weight on the back.
David W

[ChrisMiami]

Weight distribution is definitely a consideration.

[edwardb]

Sometimes I tend to want to reinvent the wheel. I’m sure the closer I get to actually having things in my hands that will die down. I do think the rear reloc is a plan (for me) and I’ve always wanted the AGM battery - thanks for the tip on that and the larger cables.

Now you mention it, fuses are a very seldom changed item. Still, I do think a more conveniently-accessed location should be found for them. I want to make maintenance super easy. Saab had most of them under the hood in front of the driver side foorbox, and it was a blessing when swapping relays.

I had another think on putting wires into the frame. I agree - bad idea for many reasons.

Reinvent away. But my advice is to at least consider the many that have gone before you. Not too many things that haven't been tried. Learning to search the forum, reading build threads, etc. are a gold mine for ideas. But I guarantee that nearly everything that's modded will have unintended consequences and often you don't find that out until you're deep into it. You're right. Having things in your hands will help to decide what makes sense and what doesn't. Example: Moving the fuse panel under the hood? Where are you going to put it? (it's crowded up there) Multiple harnesses will need to be extended. And after that, opening the hood is easier than bending down and looking up in the footbox for maybe the couple times a year you would even do that? You'll have to decide.

Ok, I'm out. Good luck.

[ChrisMiami]

I just got caught up on Paul’s video thread (Oak Creek Garage), and now I’m halfway through Matt’s (mtwarog) Gen II build. I’m going to start your build thread too, Paul. And I take your point about search skills.