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Battery Relocation.

Nebraska

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Apr 9, 2015
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Lincoln, NE
I was wondering for a second opinion on my diagram. I tried to keep it very simple. Im using 4GA welding wire.
Cant wait to hear from you guys.


*Some key points:
Im getting rid of the alternator 80A fuse replacing with 150A circuit breaker.
Im hoping to connect power to the 12V constant that feeds the fuse box
Hoping I can make the fusible link "box" disappear.
Wont install cutoff until I find a good one and extra taillight.
Forgot to label starter, 2nd rung

Wondering if I should even bother fusing or putting a circuit breaker on the starter circuit.
Also wondering if I could use a place in the fuse box for the seat belt fuse, Im trying to figure out why Mitsu made it look so important on the fusible link box.

I am an electrical tech but I am not perfect.

 
Last edited:

Nebraska

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Apr 9, 2015
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140
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Lincoln, NE
Because I'm using 4GA wire and not using any of the stock wiring. It seemed right in my head but now that you mention it I think 80A would still work.
 

strokin4dr

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In my experience, a higher than stock rating breaker is necessary to prevent it from flipping when trying to start the vehicle. Not sure if it has to do with quality control of the breakers or them being rated incorrectly. There is lots of info online with others having similar issues. A lot of the evo guys seem to go with 150-200 amp breakers. YMMV
 

Nebraska

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That's interesting and definitely something to look into. I wasn't aware the Evos and 1g were similar in that regard. I know you should fuse things based on the wire size to protect the wiring but also keeping in mind the device. I was however worried about tripping a breaker or blowing a fuse every time I would go to start the car so I decided not to fuse the starter. Also, I made this decision based on the fact that the factory never fused the starter.

If I were to put the starter circuit coming out of the distribution block I would most certainly put a 150A-200A breaker on the feed. That's using 4GA not 2GA or I would most likely need the 200A.

Been using this handy little guy made by LittleFuse I tink...

 

FlyingEagle

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Might I suggest a separate fuse setup/CB for the starter circuit. It should not be tied into the main wiring in any way.

Now, fuse the main system junction block to match the fuse rating of what is already there, so if using a CB you have to match the rating on the stock fuses - and total capacity.

If the alternator wire is being upgraded, and the alternator has a higher output, then I can see using a higher amperage fuse.

Match each leg of the system to appropriate maximums for the devices installed.

Anything that receives a higher amperage than it should, will allow too much current to flow through a circuit should it short to ground or a component malfunction and the last thing you want is an electrical fire.

Fuses save move than your components ....

Afterthought = any components being upgraded and that use more current than stock output stuff, require a rewire into the fuse block (complete replacement and repin) or separate appropriately sized wiring to be installed and run in parallel to the stock wire location (don't actually install them physically connected in parallel like an alternator setup, unless you are upgrading the wires that way for the alternator - but no reason to IMHO). Consider heat wrapping for exposed wiring, ease of access for road side repair and labels in case things are removed and you know what you are looking to replace two months later.
Heat means certain wires have to be larger to maintain capacity in the engine bay environment, than they would be otherwise inside the car.
Upgrade the grounds for the starter/engine and trans blocks to chassis, using larger wire to match the power feeds in the case of the starter. It is a full return system
 
Last edited:

Nebraska

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Lincoln, NE
That's some useful information I can go forward with, Thanks.

Although I never did fuse/CB the starter circuit, it would be a home run from the battery to starter (4GA) Did I understand that right from your post?

Also yes all wires in the diagram would be 4GA (including grounds to eliminate the bottle neck theory) except the seat belt fuse and wire. Most likely that will be relocated inside the fuse box and kept at 30A or whatever it is on the fusible link box.

As for the main fuse box, I don't believe I will use a distribution block anymore. Instead I shall go from the battery, to a 100A CB and run to the front of the car and terminate on the side of the fuse box where the stock system has a 10 or 12GA white wire that's fed directly from the stock +12V terminal. This wire is not fused, as it is tied in with the actual battery terminal clamp on the stock fusible link box. I can post some pics later when Im off work.

Cliff Notes , All wires from battery to Alternator, Starter and Fuse box (large one, Pass side, under hood) will be 4GA
Starter will not be fused
Alternator will have a 150A opening device
Fuse box will have 100A opening device.
Seat belt fusible link will be rewired into the fuse box because all other fusible links will be gone, little fusible link box = bye bye.

When designing this circuit I used my electrical theory knowledge and this post which seems like a decent write up if it was archived on here. click

Please lets keep this conversation going guys..
 

Nebraska

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Lincoln, NE
Here's an updated diagram. I'm pretty sure this should work fine. If anyone wants I can add a cutoff switch in there if they'd like to use this.

 

FlyingEagle

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Follow identical ground points, like the starter bolt/trans case location.
I've seen a few posts that directed to sites on theory for electrical wiring in the automotive environment, and following the spots the manufacturer uses should be the best spots to stick with.
Upgrading wire size will have no effect on the design except to relieve some of the 'bottle necks", and will maintain proper electrical signal paths for ECU's and such.
I'm not super savvy on being able to state exactly why, but when you read something that technical and with all the background as to why it all should be, it just makes sense.
Posting this so guys seeing this will be able to relate as to where we are coming from.

There may be ways of upgrading the path for the starter ground circuit, compared to the starter bolt location to the frame bolt hole (most common black/yellow stripe) but I have not looked into this yet. The shorter wiring is, the better, but following the design principle for common grounds/powers, etc etc.
 

CutlassJim

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Jul 17, 2006
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Location
Manchester, NH



Here's how mine is currently set up.

I have some experience in higher powered car audio and with owning cars with factory rear mounted batteries.

Grounding the battery to the body in the rear and picking it up some where in the front isn't a good idea because the "limit" for reliable current transfer through a chassis is only around a 8AWG wire. Running a dedicated 4AWG ground from the battery is fine but more expensive and takes up more space/weight so I split the difference.

There is no need for a 4AWG path from the alternator to the battery. You will never be sending 90 amps or anything close to it to the battery while charging it. You only need the big current passage for the starter.

I've had 2X 8AWG and a single 4AWG from the Alt to the fuse box and both work perfectly fine.

You want a fuse/breaker as close to all sources of current as possible in case of an accident. I have a 100 amp fuse mounted to the chassis about 6" from the alt before it heads to the fuse box and a 200 amp breaker at the battery. You need the 150/200 amp at the battery to turn the starter. A lugging starter can easily draw over 200 amps for a short period of time.
 

Nebraska

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Apr 9, 2015
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Lincoln, NE
Hey thanks man, that's great stuff there. As an electrician of sort, you have a nice diagram!
This is actually way more simple than mine.

Also flying eagle, I will use the stock grounding points so thanks for the reminder:)
 

Nebraska

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Apr 9, 2015
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Lincoln, NE
Ended up running two 2awg cables to the firewall, one power and one ground. From there I used some nifty firewall bulkheads found at speedway motors here in Lincoln (equivalent to jegs or summit.) from the firewall I grounded at the transmission with 2awg, and then the intake and inner fender wall with4awg. I also hit the opposite starter bolt with a 4 awg cable.

From the power lug I ran to the fuse box, the starter, and the 150a circuit breaker for my alternator. All with 4awg.

At the battery I have an additional ground going to a spot in the trunk for the grounds back there and lastly a 200a circuit breaker for the main power cable that runs to the firewall.
Last pic is my gauges/ wideband controller controls & power.






 

strokin4dr

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Why would you not put the circuit breaker as close as possible to the battery?
 

Nebraska

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Apr 9, 2015
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140
Location
Lincoln, NE
I did put a 200a cb right next to the battery, the alternator cb is in the front.
 

strokin4dr

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Ok, cool. I didn't see it in the pic the first time.
Keep us posted with how this setup works out for you.

-Ryan
 

FlyingEagle

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Question: The battery hold down plate and assembly all seem to be metal. Are they insulated from the frame?

If not, then that is a direct source to ground and if any tool or the terminal at the positive side end up touching it ....

I ran into this when using threaded rod through my frame, to hold my battery box in place. Rod and box are both metal, so the occasional wake up call when handling the tools!
 

Nebraska

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Apr 9, 2015
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Lincoln, NE
Great question. Actually it is not insulated from the frame and its been bothered me in the back of my mind. I was thinking about using some white plastidip on it since it started corroding out of nowhere. I guess that's what an ebay battery tray does at some point or another. Its also being held on by some 8-32 bolts (babydick size /ubbthreads/images/graemlins/idea.gif)but Im going to be putting in 3/8 bolts to hold it down, and that's when Ill paint it
 

Nebraska

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Apr 9, 2015
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Location
Lincoln, NE
Worked great! Started right up, had a huge boost leak that turned out to be the pcv. Small leak sounds like it's coming from turbo): bye bye turbo seals!
 
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