Howdy

I'm collecting materials to put the battery in the trunk of my demon and I have a bunch of questions. It seems like a pretty simple process, but there are some details I want to get right.

First, here is my plan- please point out any holes or dangerous missteps!

I want to bolt down a sealed maintainance free battery in the rear left of the trunk, with a 2 or 0 gauge primary wire to the trunk floor (cleaned to bare metal) for ground and a 0 gauge wire up to the big terminal on the starter. The motor will be grounded to the frame and or firewall with 2 or 0g. From the starter terminal I will put a 4g wire to an audio style splitter (like the competition stereo guys use to wire multiple amps) with four 8g outputs for the big +'s on my relays- horn, fuel pump, fans, and stock harness + connection.

My Questions:
Can I put a fuse inline just after the battery on the big + cable? I already have one of those inline fuse holders and some 100 amp fuses. Will that both burn before the big cable starts a fire if it shorts, and also not melt if I have to crank the starter motor more than average in case of flooding, cold start, etc? How many amps does my new style mini starter pull?

Who is a good supplier for relays? Right now I have some cheesy taiwan crap from autozone, waiting to strand me. I like the idea of a bigger box that plugs in relays from the top like on a 92 cherokee I once had, but I don't need that many and the aftermarket relay blocks I've seen are too much money. I would be happy with relays that have a mounting provision, so I can make a neat row of them where the battery used to be.

Last, my alternator needs replacement. I would like to go with a nice big one to support my fans, fuel pump, etc. I already have the dual field type, so I would only need to upgrade the output wire, right? Which alternator is reasonable, and what guage wire should I use as an upgrade?

Thanks
radar

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madam im adam

Old Car Parts Northwest has nice new (not "remanufactured") 78-amp Chrysler alternators.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks Dan, I'll look into it this week. Its always good to have more resources for parts. You are the one who put me on to car part dot com too!

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madam im adam

I'd run two power lines.

One power line (fused) for everything but the starter motor.

Then for the starter motor, I'd use a ford-type remote relay at the battery so that the heavy-gauge wire running to the starter motor is only HOT when your starting the engine.

Just thinking that any fuse big enough to handle the starter load might not blow with an intermittent short on the big cable.............

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

That's a really good idea. In fact, I'd be tempted to put a continuous-duty solenoid-style relay at the battery for the "everything else" feed, too, so that turning off the ignition would depower that, as well. Everything except the minor consumers that need power even with the key off.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

May want to run a ground the length of the car as well to the block. I wouldn't trust 30-40 year old spotwelds with all that current, and even if they were new thats mucho current for sheetmetal.

Actually, the sheet metal ground worked fine when I did this on my '66 Dart. Also, a 2 AWG + cable is plenty big. No need for the weight and expense of larger cable. I had a group 24 battery in the right rear of the trunk with 2 AWG cable, the ground cable from battery right to the trunk floor and it started the 10:1 318 easily. The mini starter didn't hurt either.

Currently (ooh, bad electrical pun) my '67 Valiant has a lawn tractor battery and mini starter. Works fine, saves weight and made space for a radiator overflow bottle. For the race car project I'm going to try a large-ish motorcycle battery I have and another mini starter.

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Joshua

I'm not saying it wouldn't work fine, I'm sure there are thousands of examples of it working. I guess the thought of sending starter current through sheet metal irks me. If I was doing it I would run another cable just for peace of mind. Doesn't have to be as thick as the positive - say 4 awg to save space. From block or trans to trunk floor, and battery post to same stud on trunk floor.

I have seen so many sets of headlamps made so much brighter by doing nothing more than running proper grounds rather than going through sheetmetal, that I have to say "run a real ground cable".

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

some forklifts and other industrial trucks use ground-isolated electrical systems as part of corrosive-environment accessory packages for that reason.
all electric forklift trucks i have seen use a ground-isolated electrical system. in a typical 48V, 500-750aH battery-powered truck, even the heavy frame of a forklift cant be trusted with all that current.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

If I may remind everyone that a battery in the trunk needs to be well vented; an article many years ago (maybe in Car Craft?) suggested moving the battery to the trunk, but forgot to mention the venting. Subsequent letters to the editor described a couple of explosions that resulted.

Our Mopar club was going to move the batteries into the trunk of our Fury car, so I built a nice little control box described at:
http://www.tidewatermoparclub.com/NEWSL ... 06/box.pdf

Unfortunately, that project has since been canceled due to robberies/going out of business/military deployments/etc.