Trunk mounted battery...where to run alternator output?

[cpd004]

If mounting a battery in the trunk and running the + up front to the starter, would you then run the alternator to the same lug on the starter? Specifically in an Ls swap if that matters.

[GregWeld]

If mounting a battery in the trunk and running the + up front to the starter, would you then run the alternator to the same lug on the starter? Specifically in an Ls swap if that matters.

That works.


Or you can create a positive power take off using a COVERED common buss bar -- then you have power in the engine bay for electric fan relays or anything else you'd need power for. Run the big positive from the battery to buss bar -- make a short jumper from there to the starter etc.





http://i919.photobucket.com/albums/ad33/gregweld/Fun%20Fotos/_35.gif (http://s919.photobucket.com/user/gregweld/media/Fun%20Fotos/_35.gif.html)

[GregWeld]

I've used this version from West Marine a couple of times -- I like that it's nice and compact -- and the connector ring and screws are Stainless Steel......






http://i919.photobucket.com/albums/ad33/gregweld/Fun%20Fotos/540658.jpg (http://s919.photobucket.com/user/gregweld/media/Fun%20Fotos/540658.jpg.html)

[DBasher]

I've used this version from West Marine a couple of times -- I like that it's nice and compact -- and the connector ring and screws are Stainless Steel......






http://i919.photobucket.com/albums/ad33/gregweld/Fun%20Fotos/540658.jpg (http://s919.photobucket.com/user/gregweld/media/Fun%20Fotos/540658.jpg.html)

We used something very similar on the delivery I had. Marine supply stores have great electrical components without the "hot rod" mark up.
:thumbsup:

[Woodrow]

I did mine a little different. As I used the solenoid in the trunk so the long large line from the battery isn't live all the time, then from the alternator I went to this terminal block from Jegs.

http://www.jegs.com/i/JEGS+Performance+Products/555/10521/10002/-1

Then I connected one post to the alternator, then all other accessories, plus the charge line back to the battery in the trunk (8 gauge, I think) on the other post. Then for safety I connected the 2 posts with a fused link wire in the event something overloads. All tucks up into the block and seems to work well.

Woodrow.

[cpd004]

I did mine a little different. As I used the solenoid in the trunk so the long large line from the battery isn't live all the time, then from the alternator I went to this terminal block from Jegs.

http://www.jegs.com/i/JEGS+Performance+Products/555/10521/10002/-1

Then I connected one post to the alternator, then all other accessories, plus the charge line back to the battery in the trunk (8 gauge, I think) on the other post. Then for safety I connected the 2 posts with a fused link wire in the event something overloads. All tucks up into the block and seems to work well.

Woodrow.


Are you saying you used a Ford type solenoid?

[randy]

rear battery
ran line up the passenger side of the car including the ground
2 bulkhead connectors on the floor board + and -
Other side of the bulkhead connector connects to the starter
Wire hidden from the starter to the alternator.

DSE kit is what i used

[cpd004]

From what I've read, there are many variations to what people have done. This is what I am going for so far:

An XS D1200 battery mounted in a simple mount and hold down in the trunk.

2 AWG positive from the trunk to the lug on the starter. Not fused and not sure if it is ok to be live all the time?

4 AWG Fused some way to the same lug from alternator to starter

a 2nd 4 AWG to a distribution block like you guys have posted above from the alternator for the ECM and fuse panel of the car.

2AWG negative from battery to body in trunk along with multiple Negative grounding cables where needed.

A Negative distribution block some where in the engine bay from the frame (or engine...not sure if a block is even needed).

The car has no power windows, locks, defrost, etc. I only have a radio, the ECM/TCM, electric fans and the lighting.

Any opinions/suggestions are greatly appreciated.

[alongfortheride]

Madd electrical has a very nice write up on mounting the battery in the trunk. He advises not to run your starter cable live at all times. I am looking for the link. When I find it I will post.

[cpd004]

Madd electrical has a very nice write up on mounting the battery in the trunk. He advises not to run your starter cable live at all times. I am looking for the link. When I find it I will post.

I just found the link. Thanks!

[randy]

now your starting to make me think it would be a good idea to run a inline fuse from the battery to my bulkhead

[Woodrow]

Are you saying you used a Ford type solenoid?

Yes, using the Ford solenoid.

[cpd004]

Mad Electrical has 2 kits that others have recommended: TM2 and ST1.

On a side note...I was looking at my G8 which has a trunk mounted battery and it appears the + side is live all the time. It appears to go from the battery terminal along the drivers side of the car to a positive distribution block and then on down to the starter. It also appears to be at most a 2 gauge wire.

[WSSix]

I designed my own system. It's similar to the Mad Electric one. I have a 2 AWG cable going from the battery to a Ford style starter solenoid that's mounted behind the battery. Then the battery cable goes all the way to the front. It's only live during cranking. The ground goes straight to the frame rail after coming off the battery.

The alternator return is 4 or 6 AWG and goes all the way back to the battery through a 100 or 150 AMP circuit breaker that's also mounted behind the battery. Yes, the alternator cable is live the whole time. However, you can't easily put a circuit breaker/fuse on the starter cable so protecting the alternator cable is easier and smarter IMO. Something goes wrong and the system is disconnected and the car is protected.

I have a junction post on the firewall for power take off to the rest of the car. It's below the AC box between the frame rail and firewall essentially. It's well protected and a pain to get to if needed. I also have a smaller circuit breaker right off the post for the rest of the car. It's much smaller than the alternator one and protects the wires between the junction point and fuse panel in the interior. The electrical fans have their own circuit breaker and relays mounted to the inner fender on the driver's side. Off hand, I believe that's the only power circuit not going to the inside.

My attitude towards more circuitry is to not play games with protection. You have to protect the wires to what their capable of handling. I could have eliminated the circuit breaker off the junction post on the firewall and allowed the circuit breaker in the trunk for the alternator to handle it. However, it's a big breaker. The wires off that junction post could melt before they trip the circuit breaker in the trunk. An inexpensive and small circuit breaker is money well spent IMO.

[cpd004]

So the crank wire would now go to the Ford solenoid in the trunk and would not need to go to the starter any more with this set up.

I've read people using 4 and 8 gauge from the alternator back to the battery.

I like the idea of breakers over fuses, although a handful of fuses wouldn't be much to carry around either way.

One install I saw uses Marinco breakers. They are normally used in marine applications but look better than some of the automotive ones I've seen. They are a few dollars more though.

What brand of breakers did you go with?

[Vince@Meanstreets]

So the crank wire would now go to the Ford solenoid in the trunk and would not need to go to the starter any more with this set up.

I've read people using 4 and 8 gauge from the alternator back to the battery.

I like the idea of breakers over fuses, although a handful of fuses wouldn't be much to carry around either way.

One install I saw uses Marinco breakers. They are normally used in marine applications but look better than some of the automotive ones I've seen. They are a few dollars more though.

What brand of breakers did you go with?

No need to add the Ford solenoid on an LS starter. You are only adding weight and easing the job for thieves. People started adding Ford solenoids to combat starter heat soak. Which is non existent in modern LS starters.

On trunk mounted battery systems, I like to run a bulk head stud on the firewall near the starter. Then just run a 10" long 2 ga to the starter. 8 ga to the alternator from the firewall bulk head or the radiator support power feed. I run a radiator support bulk head to feed the fan and headlamp relays.

[cpd004]

Live all the time? This is the way OEM's do so I don't see why it should be a problem here. Do you have a pic of the bulk heads you use?

[Vega$69]

Live all the time? This is the way OEM's do so I don't see why it should be a problem here. Do you have a pic of the bulk heads you use?

The OEMs do it because they are designed from the get go to do it.

I run the ford solenoid for the started wires and a fusible link on the ALT wire

[MtotheIKEo]

I used to use the circuit breakers when I designed electrical systems for utility trucks and cranes. They work awesome, are compact, and you can easily disconnect your electrical at the battery if you are working on it without any tools.
http://www.amazon.com/Bussmann-CB185-150-Type-Circuit-Breaker/dp/B001PT7XBE

[Vince@Meanstreets]

Live all the time? This is the way OEM's do so I don't see why it should be a problem here. Do you have a pic of the bulk heads you use?

I used to use the circuit breakers when I designed electrical systems for utility trucks and cranes. They work awesome, are compact, and you can easily disconnect your electrical at the battery if you are working on it without any tools.
http://www.amazon.com/Bussmann-CB185-150-Type-Circuit-Breaker/dp/B001PT7XBE

those work fantastic...There was a thermal type that I was researching but can't seem to find right now.

cpd004, firewall pass through... http://www.summitracing.com/parts/sum-g1431-red

[cpd004]

I appreciate all the help!

I've read a few different articles on breaker sizing (and my head is spinning)...it appears as though I would need a 150 amp breaker near the battery on it's way up to the starter. Does this sound correct?

Also, I'm thinking of going with a maxi fuse holder for the charge wire from the alternator. I think 8 gauge as suggested above will work just fine, but can't seem to find an appropriate fuse rating. The reason I'd like to go with a maxi fuse is that I can then use a maxi fuse block like what I have now and just a bigger one for the charge wire. My current one has 2 fuses...one that supplies power to the cars fuse panel and the other is for the electric fans.

Vince, I like what you did with the bulkhead down low and near the starter. It makes things nice and clean.

[ilikeike]

Heres one way.

You don't have to use the relay on the starter curcuit,some just use a jumper at the starter.
http://i884.photobucket.com/albums/ac49/dsmallen/258xyiu_zpse954689d.jpg (http://s884.photobucket.com/user/dsmallen/media/258xyiu_zpse954689d.jpg.html)

[Vince@Meanstreets]

I appreciate all the help!

I've read a few different articles on breaker sizing (and my head is spinning)...it appears as though I would need a 150 amp breaker near the battery on it's way up to the starter. Does this sound correct?

Also, I'm thinking of going with a maxi fuse holder for the charge wire from the alternator. I think 8 gauge as suggested above will work just fine, but can't seem to find an appropriate fuse rating. The reason I'd like to go with a maxi fuse is that I can then use a maxi fuse block like what I have now and just a bigger one for the charge wire. My current one has 2 fuses...one that supplies power to the cars fuse panel and the other is for the electric fans.

Vince, I like what you did with the bulkhead down low and near the starter. It makes things nice and clean.
The 150 should be fine at the battery lead.

For the alternator I usually check full system loads but the maxi fuse I usually run a 70 amp.

8ga should be fine. It's rated for 75 amps. Doubt you output would see that.

[cpd004]

One other question...what is the stud size on the breaker listed? Can't seem to find it anywhere.

[MtotheIKEo]

One other question...what is the stud size on the breaker listed? Can't seem to find it anywhere.

1/4-28
http://www.cesco.com/b2c/product/Bussmann-CB185-135-Automotive-Circuit-Breaker/28019

[Vince@Meanstreets]

1/4-28
http://www.cesco.com/b2c/product/Bussmann-CB185-135-Automotive-Circuit-Breaker/28019

You can buy blank 0/0 1/0 battery cable lugs and drill them to size.