Trunk Mount Battery - Wire Routing

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mopowers

mopowers

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For those with trunk mounted batteries, how do you prefer to route the starter cable and alternator charge wire?

I'm doing some electrical planning for my 66 BB Dart build and am trying to figure out the best way to rout these large cables (e.g., along the frame rails, through the interior, etc.)
 
FWIW...I routed the batt cable along the rear if the tailpanel and then through the pass compartment along the normal LH cable channel by the door sill. Batt cable is dead except during crank using a Ford relay in the trunk.. The alt 4ga charge wire is also there but once in the trunk, makes it over to RH side of rear seat and then straight back to battery (actually a megafuse holder then the batt). They both go through a grommet in the firewall clutch hole.
Works for me!
 
I too use a Ford solenoid and go through the clutch hole as well.Yes I know the wire is near the header but I've since pulled it back.

Resized_20210405_163506.jpeg
 
Thanks guys. I like that idea for routing the battery cable. I too will be using a Ford relay in the trunk.
 
I have mine going to an insulted standoff lug on the frame rail. Gives me a jump start point ala the newer cars with the batteries hidden behind the bumper. Its just acts as the + battery lug to the remote battery. 2G welding cable to the rear battery box up along the floorboard.
 
Can anybody draw a wiring schematic?
This would be a awesome thing to reference.
 
Do mine the same as @Demonx2

I run my cable inside. Forward and across the shock mount area then up the dr side sill panel channel. Through the clutch gormmet. Real nice access to the starter from there.
lEhqKWf.jpg


Alternator charge line run in the pass side sill channel.
 
crackedback said:
Do mine the same as @Demonx2

I run my cable inside. Forward and across the shock mount area then up the dr side sill panel channel. Through the clutch gormmet. Real nice access to the starter from there.
View attachment 1715844126

Alternator charge line run in the pass side sill channel.
Click to expand...

Im considering mounting the battery on the drivers side instead of the passenger side. Saves the extra cable length plus the engine isn’t centered in the car, so moving the battery to the drivers side should reduce the amount of suspension preload needed to make the car leave straight.

Thoughts?
 
Does anyone run a ground wire up front as well?
 
crackedback said:
Do mine the same as @Demonx2

I run my cable inside. Forward and across the shock mount area then up the dr side sill panel channel. Through the clutch gormmet. Real nice access to the starter from there.
View attachment 1715844126

Alternator charge line run in the pass side sill channel.
Click to expand...

That's a really clean way to route everything.
 
Rat Bastid said:
Im considering mounting the battery on the drivers side instead of the passenger side. Saves the extra cable length plus the engine isn’t centered in the car, so moving the battery to the drivers side should reduce the amount of suspension preload needed to make the car leave straight.

Thoughts?
Click to expand...
It goes against conventional methods that normally work well. The passenger side tire is the normal side tire that could use a little weight above/behind it.

matthon said:
Does anyone run a ground wire up front as well?
Click to expand...
This should not have to be. I am having an issue right now and something has been suggested to me. If needed, there is probably enough rust in between the rear mounted battery and the engine to not allow a good ground. Having done a battery relocation kit before, there was no issue. Did it this time on the current car, I’m like WTH?
 
matthon said:
Does anyone run a ground wire up front as well?
Click to expand...
I think it was @crackedback that made the suggestion that I followed. I welded a nut to the frame in the rear below the battery. Then I ran the ground cable to it through the trunk floor and bolted it up. Very short ground cable needed!
I also welded a nut on the inner front frame rail that I ran a ground cable from the RH rear cyl head hole to this welded nut. Simple enough! IMHO, you cannot have too many grounds!
 
matthon said:
Does anyone run a ground wire up front as well?
Click to expand...
I did. To the block. I use this post to go to chassis. I also use this post to go back to dash. Might be over kill.

I like the ford thing. Ill have to look into that.
 
clementine said:
I like the ford thing. Ill have to look into that.
Click to expand...
Others, even Chrysler, used seperate solenoid relays at various times. Its just easiest to get one at the parts store by looking up a Ford.
:)

It keeps the big cable to the starter off. Only when the key switch goes to start does the solenoid get the power to connect it to the battery cable.
This is basically @crackedback's schematic - I just moved things around so it was easier for me to read.
upload_2021-12-30_14-51-23.png
 
Rat Bastid said:
Im considering mounting the battery on the drivers side instead of the passenger side. Saves the extra cable length plus the engine isn’t centered in the car, so moving the battery to the drivers side should reduce the amount of suspension preload needed to make the car leave straight.

Thoughts?
Click to expand...
Because of the physics of engine rotation, the axle wants to lift on the passenger side rear. You want your weight bias on the right rear of the car.That is also why Mopar installed stiffer springs on the passenger side,,both super stock springs and factory axle package cars, track pak and super track pak.
 
Awesome guys! Big thanks.
Mattax said:
Rob posted his schematic in post #24 of questions about battery disconnect wiring
Click to expand...

Mattax said:
Others, even Chrysler, used seperate solenoid relays at various times. Its just easiest to get one at the parts store by looking up a Ford.
:)

It keeps the big cable to the starter off. Only when the key switch goes to start does the solenoid get the power to connect it to the battery cable.
This is basically @crackedback's schematic - I just moved things around so it was easier for me to read.
View attachment 1715844667
Click to expand...
 
The tank and myself ride on the driver side of my pickup. 16gallons x 8lbs and me at 175 wet is 300 lbs on one side. At least the battery is on the passenger side! My remote battery is trunk mount behind the passenger rear tire. It's only 40 lbs.
 
clementine said:
I did. To the block. I use this post to go to chassis. I also use this post to go back to dash. Might be over kill.
Click to expand...
Grounds are never overkill imo.

For the record, I don't have a trunk mounted battery, but I do have a ground hub in the trunk, the sending unit, tank, and reverse lights are grounded to it, and a ground wire runs from that to a ground hub in the front.
Everything is grounded to the front hub, hub to frame and battery, frame to engine, dash/gauges to welded bolt behind dash, etc.

No more chasing my tail and scratching my head over electronicals.
 
Mattax said:
Others, even Chrysler, used seperate solenoid relays at various times. Its just easiest to get one at the parts store by looking up a Ford.
:)

It keeps the big cable to the starter off. Only when the key switch goes to start does the solenoid get the power to connect it to the battery cable.
This is basically @crackedback's schematic - I just moved things around so it was easier for me to read.
View attachment 1715844667
Click to expand...

I’m in process of rewiring now. I have the Ford relay in the trunk, but I have eliminated the factory relay under the hood. My NSS is part of my shifter, so I ran the ignition switch trigger wire to the switch on the shifter, then back to the Ford relay. I’m running a Painless fuse box, my alternator cable goes to the fuse box and the fuse box runs back to the battery in the trunk. I also have a 4 circuit fuse block in the trunk now to power my radio/amp, my fuel pump and my EFI, with one circuit empty for now. I wanted direct runs to the battery for those items instead of tying them in somewhere.
 
72Duster440 said:
I wanted direct runs to the battery for those items instead of tying them in somewhere.
Click to expand...
When the alternator is producing enough power at 14 Volts, then that's the power source.
The advantage of tying in close to or after the battery is:
a. times when the battery is the power source
b. equipment that may be sensitive to the electrical noise from the alternator.
I'm not the one to explain how a battery can dampen out some of that noise but accept it as realty.
With EFI and an AMP, your strategy is probably a good one.
Just make sure the alternator output line can carry the currents for that stuff and maximum battery charging without much resistance.
 
I agree, the alternator provides the power and the battery is like a buffer. I had everything wired in to the stud on the starter relay, I was using that as my power distribution block. I have some bad ignition interference on the radio when the ignition is on, and I am in the process of installing a new radio with a small amplifier, so I figured it's time to give the EFI and radio their own home run to the battery. Everything has been working great for 6 or 7 years since I installed the Painless harness. I never addressed the starting circuit at that time, so I figured if I am touching some other wiring, now is the time to upgrade the starting circuit too.
 
Do you guys run relays on everything? While I'm planning out the wiring for items in my trunk, I'm wondering if - in addition to the fuel pump - it's worth running relays for things like tail lights, reverse lights, and brake lights. Thoughts?
 
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