2G 1995 Eagle Talon: Battery relocation to trunk.

[SikhDSM]

Sorry for the noob question: I know there is countless threads on this, but I cannot seem to find the answer I am in search of.

I want to relocate the battery to the trunk using this kit:
https://www.enjukuracing.com/produc...e=1&gbraid=0AAAAAD_vUIB_aB1IDrieYcHt1l0UOLy7C )

I am wondering if I can wire it up like it shows in the diagram or if anybody has insight: Battery to Starter to alternator. It seems very straight forward?
Also another thought is do I need to run a wire for the fuse box as well or does that have its own connection?

Any guiding, diagram, and help would be greatly appreciated

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[We're on Boost]

I would ask them a few questions:

What is the gauge of wire C and wire B? They say "Properly AWG sized power wires". Yaah, tell me what gauge they are.
Show me better closeup pictures of the firewall pass-through part (the red thing), both ends of it. And how long is the electrical stud on the engine bay side of it, because maybe I would want to run wire F to it as well as wire E.
What gauge is wire F?
Their longest wire F is only 38 inches and I'm not so sure that's long enough to go to either place, so you might wind up making your own wire F.
Wires E and F are in the engine bay, so I would want to know what the temperature rating of the insulation is, what material it is, and what SAE standard it meets. Battery cable and engine compartment wire usually meets SAE J-1127 or SAE J-1128. The better stuff is temp rated to 125 deg C.
When you use wire F to the bulkhead passthru or to the starter, you are apparently not running the stock wire anymore that goes from alternator to the stock alternator fuse, and I'm not exactly sure right now if that's a problem or not. Other people in here would know better than me probably, about that.

 

[SikhDSM]

Thank you for prompting some questions, I went ahead and sent that over to see if they can give us some feedback back on what “proper gauge” is and “SAE” rating etc.

And yeah that’s were I am getting confused, can I just hook it up normally on top of the wire (F) relocation kit on the alternator? That way the fuse box is still connected?

Potential Wire diagram

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[Mahreeoh17]

From what I read each component needs its own wire from the battery, or you'll have charging issues.

 

[We're on Boost]

And yeah that’s were I am getting confused, can I just hook it up normally on top of the wire (F) relocation kit on the alternator? That way the fuse box is still connected?

That's the part I'm not so sure about too. I think you are asking here if you could leave the stock wiring in place that goes from the alternator B post to the stock fuse box/power distribution box, and then also put their wire F on the alternator B post and run F to either how they show it or to their firewall passthru post.
I think that's one possibility.

You do have to have a little bit of care for the alternator B post because they can break off. Big heavy or multiple wires on something that vibrates a lot, the B stud can fatigue, and break off. See Vegas Smith's build thread for his experience with that last year, post 774.

I keep thinking there should be a way to just have one brand new healthy cable going from the alternator B post to the engine bay side of that firewall passthru, and then have another cable going from the firewall passthru to the battery side of the stock fuse box. But I'm not seeing it clearly at the moment, so would be nice to have input from one of the more electrical guys. You'd have multiple connections on the passthru stud but at least it isn't vibrating nearly so much as the alternator is.

Having a larger than stock wire from alternator to battery is an upgrade that people find gets them higher voltage to everything, and you can see the voltage is higher in ECMlink.
See for example the build thread My Old High School Car starting from post 315.

 

[SikhDSM]

Another thought I had is if I just get like a battery junction box, something like this but obviously more thicker gauge wire and that can fit).

https://www.racetronix.biz/k/battery-junction-block-kit-cableblock/bpc-001k


Put this essentially where there battery positive terminal is in the engine bay, and ship the wire coming out the other end of the box to the trunk with appropriate gauge wire (whatever that maybe).

I would ask them a few questions:

What is the gauge of wire C and wire B? They say "Properly AWG sized power wires". Yaah, tell me what gauge they are.
Show me better closeup pictures of the firewall pass-through part (the red thing), both ends of it. And how long is the electrical stud on the engine bay side of it, because maybe I would want to run wire F to it as well as wire E.
What gauge is wire F?
Their longest wire F is only 38 inches and I'm not so sure that's long enough to go to either place, so you might wind up making your own wire F.
Wires E and F are in the engine bay, so I would want to know what the temperature rating of the insulation is, what material it is, and what SAE standard it meets. Battery cable and engine compartment wire usually meets SAE J-1127 or SAE J-1128. The better stuff is temp rated to 125 deg C.
When you use wire F to the bulkhead passthru or to the starter, you are apparently not running the stock wire anymore that goes from alternator to the stock alternator fuse, and I'm not exactly sure right now if that's a problem or not. Other people in here would know better than me probably, about that.

This is the information I received:
The main battery run is awg4. Other wires are awg 6.
The temp rating and sae is unknown.

 

[We're on Boost]

This is the information I received:
The main battery run is awg4. Other wires are awg 6.
The temp rating and sae is unknown.

Aww that's really not very good.
The main battery run wire C, that wire is 12.5 feet long. I would use a 1 gauge there. A lot of people would say to use a 0 gauge there.
6 gauge for wire F (the alternator wire) is ok but it's not much of an upgrade from stock. The stock alternator wire is actually 2 wires in parallel that are about 10 gauge each. In parallel they are about equivalent to a single 7 gauge wire.
I think a good upgrade size for the alternator wire would be 4 gauge. Or even 2 gauge.
Not knowing anything about the insulation rating or standards met is poor. Really poor.
The bulkhead fitting they use and the 200 amp circuit breaker might be interesting if we knew everything about them. But at the moment I don't know anything about them!

For the long wire from trunk to firewall, the 12.5 foot wire C, here's a number cookout.
You are interested in how much voltage is lost in that wire when you are cranking the starter. Because you want as much voltage as possible to make it to the starter. Voltage drop in the wire is going to be V=IR. The R is a standard table value (resistance) that you can look up for any copper wire gauge. The I is current in amps drawn by the starter, and I'm just going to estimate that at around 150 amps because most of these starters are about 1.4 KW and voltage during cranking is about 10 volts. Anyway, let's say 150 amps going to the starter.

Resistance of 4 gauge wire is 0.2485 ohms per 1000 feet.
Resistance of 12.5 feet of it would be:
12.5/1000 times 0.2485 = .003106 ohms
V=IR at 150 Amps:
V=150 (.003106) = 0.466 volts lost in the 12.5 foot wire to the firewall
Kind of a lot, almost half a volt thrown away in that one wire when you are cranking.

For comparison,
1 gauge wire is 0.1239 ohms per 1000 feet.
You would lose 0.232 volts in the 12.5 foot wire when cranking.

0 gauge wire is 0.09827 ohms per 1000 feet.
You would lose 0.184 volts in the 12.5 foot wire when cranking.

The reason you don't need as big a wire from the alternator is because there is less current there. But it's still nice to have minimal voltage drop in your alternator wire. I mean I'm getting along "ok" with the stock wiring from alternator to the main fuse box. But I do see in ECMlink that my voltage drops over half a volt when the 2nd fuel pump kicks in and the boost goes up (so the pumps are working harder, taking more current) so I might beef up my alternator wire some day.
Table of AWG wire sizes

 

[SikhDSM]

okay, so your going to hate me I got very impatient last night. And switched the diagram. I obviously ditched the enjuku kit and mocked up my own and ordered it.

I went with 2gauge wire running from trunk (battery positive) to a moroso firewall pass thru.
I hope 2 gauge is still sufficient,
I did do a load test yesterday with current dropping min 11.16v, so I can compare after the relocation.

After the moroso firewall pass thru, I have a distribution block which I will just wire the existing wires that would be connected to (positive) battery up front.
I read that having the distribution block there acts like the (battery postive) terminal is still there.

Then obviously have the ground in the trunk and hopefully it’s all dandy, I don’t see anything wrong other than making sure that everything is crimped securely and tighten?
Would you foresee any issues doing this method instead?

Essentially won’t be touching any wires from the harness/fusebox and leaving everything the way it is connected on starter and alternator.

Aww that's really not very good.
The main battery run wire C, that wire is 12.5 feet long. I would use a 1 gauge there. A lot of people would say to use a 0 gauge there.
6 gauge for wire F (the alternator wire) is ok but it's not much of an upgrade from stock. The stock alternator wire is actually 2 wires in parallel that are about 10 gauge each. In parallel they are about equivalent to a single 7 gauge wire.
I think a good upgrade size for the alternator wire would be 4 gauge. Or even 2 gauge.
Not knowing anything about the insulation rating or standards met is poor. Really poor.
The bulkhead fitting they use and the 200 amp circuit breaker might be interesting if we knew everything about them. But at the moment I don't know anything about them!

For the long wire from trunk to firewall, the 12.5 foot wire C, here's a number cookout.
You are interested in how much voltage is lost in that wire when you are cranking the starter. Because you want as much voltage as possible to make it to the starter. Voltage drop in the wire is going to be V=IR. The R is a standard table value (resistance) that you can look up for any copper wire gauge. The I is current in amps drawn by the starter, and I'm just going to estimate that at around 150 amps because most of these starters are about 1.4 KW and voltage during cranking is about 10 volts. Anyway, let's say 150 amps going to the starter.

Resistance of 4 gauge wire is 0.2485 ohms per 1000 feet.
Resistance of 12.5 feet of it would be:
12.5/1000 times 0.2485 = .003106 ohms
V=IR at 150 Amps:
V=150 (.003106) = 0.466 volts lost in the 12.5 foot wire to the firewall
Kind of a lot, almost half a volt thrown away in that one wire when you are cranking.

For comparison,
1 gauge wire is 0.1239 ohms per 1000 feet.
You would lose 0.232 volts in the 12.5 foot wire when cranking.

0 gauge wire is 0.09827 ohms per 1000 feet.
You would lose 0.184 volts in the 12.5 foot wire when cranking.

The reason you don't need as big a wire from the alternator is because there is less current there. But it's still nice to have minimal voltage drop in your alternator wire. I mean I'm getting along "ok" with the stock wiring from alternator to the main fuse box. But I do see in ECMlink that my voltage drops over half a volt when the 2nd fuel pump kicks in and the boost goes up (so the pumps are working harder, taking more current) so I might beef up my alternator wire some day.
Table of AWG wire sizes

What about hardwiring the fuel pumps?

 

[We're on Boost]

What about hardwiring the fuel pumps?

I do have both fuel pumps hard wired to the battery + terminal. Two 10 gauge wires going from the battery + terminal, each wire to one pump. My battery post clamp is a mini distribution block. It has four bolts to connect cables to.
But that's hardwiring to the battery. It could be improved by upsizing the wire that goes from alternator to battery + terminal. So that I might do someday.

Would you foresee any issues doing this method instead?

Actually I think this will be OK. I'm glad you are doing this instead of the enjuku kit which you would have had to modify the heck out of anyway.

Essentially won’t be touching any wires from the harness/fusebox and leaving everything the way it is connected on starter and alternator.

Yep I think that's fine and you can always upgrade any of that stuff later if you wanted to.

I read that having the distribution block there acts like the (battery postive) terminal is still there.

Yep, just use the distribution block as if it was the battery + terminal.

I did do a load test yesterday with current dropping min 11.16v, so I can compare after the relocation.

Could you elaborate a little bit on how you did this load test? I mean just because there's different ways people would think how to do this, so curious what you did.

a moroso firewall pass thru

Could you give me a link to this piece, I'd like to take a look at it.

Then obviously have the ground in the trunk and hopefully it’s all dandy, I don’t see anything wrong other than making sure that everything is crimped securely and tighten?

Yes, 2 gauge again for the ground wire in the trunk, and this wire can be pretty short which helps.
So I guess you'll be making up your own wires. If you are going to crimp the ends on, here's a nifty tool for crimping large sizes. I have one of these that I used to make some 4 gauge ground wires for my car. I only would warn about one thing with this tool, and that is I don't think the biggest die is big enough to do a 0 gauge crimp connector. I could try to figure out if it would do a 2 gauge connector if you want. Anyway, it's this "Pittsburg" Harbor Freight thing, and I see the price is still pretty low, hardly any more than when I bought one:
PITTSBURGH Hydraulic Wire Crimping Tool

Or, some guys solder these things with a torch.

 

[SikhDSM]

Actually I think this will be OK. I'm glad you are doing this instead of the enjuku kit which you would have had to modify the heck out of anyway.

Honestly it was way cheaper too so win win.

Yep I think that's fine and you can always upgrade any of that stuff later if you wanted to.

That is the plan, go stand alone with PnP adapter, then eventually custom wiring harness.

Could you elaborate a little bit on how you did this load test? I mean just because there's different ways people would think how to do this, so curious what you did.

I took a multimeter and put it to the battery, before stating i took a reading and when starting I took a reading (which is the load test), then obviously you have your reading after when idling if you alternator Is functioning properly.
-Basically the first reading is to make sure the battery health is good when car is switched off.
The second reading right when starting the engine is the most crucial. When starting it you can read how much power was withdrawn to start the motor, you want it above 9.6 volts other wise you are digging into your battery.
So I just took these numbers as a precautionary to see if I will have any battery drain issues when battery is in the trunk.
Followed this link below.

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Could you give me a link to this piece, I'd like to take a look at it.

Moroso Thru-Panel Battery Connector (74145)

The Moroso thru-panel battery connectors can be used wherever a battery cable goes through a firewall or other similar panel. They fit in a 1 1/4 inch diameter hole and connect with a standard 3/8 inch stud. Plastic bulkhead design.

stmtuned.com

Yes, 2 gauge again for the ground wire in the trunk, and this wire can be pretty short which helps.
So I guess you'll be making up your own wires. If you are going to crimp the ends on, here's a nifty tool for crimping large sizes. I have one of these that I used to make some 4 gauge ground wires for my car. I only would warn about one thing with this tool, and that is I don't think the biggest die is big enough to do a 0 gauge crimp connector. I could try to figure out if it would do a 2 gauge connector if you want. Anyway, it's this "Pittsburg" Harbor Freight thing, and I see the price is still pretty low, hardly any more than when I bought one:
PITTSBURGH Hydraulic Wire Crimping Tool

Yep yep! We are on the same page. This will all be going down tom so feel free to check in ! I haven’t found an ideal tray that I would like to mount in the trunk yet so still pondering that might just go with a universal one at this point unless you suggest one.

 

[We're on Boost]

That battery load test video from 13 years ago is a good one, and he was using a Fluke 87 with Min Max feature which is a really good way to do it if you have Min Max on your meter. The way I understand the Min Max spec for the 87 is that it will catch any min or max that has a duration of 1 millisecond or more. So that's pretty good. If you are using a different meter, it would be different. Or if you are relying on seeing what shows on the meter display in real time, you'd be limited by the update rate of the display, and that is usually only a few updates per second. (4 updates per second for the Fluke 87).
BTW, ECMlink samples around 20 to 25 times per second, I think ? so that is pretty good.

The Moroso 74145 bulkhead connector looks good.
I think I remember a few people in here using a Moroso battery box for their trunk mount batteries. The Moroso 74051 shown by STM looks pretty good to me.

Looks like it's all going ok!

 

[SikhDSM]

That battery load test video from 13 years ago is a good one, and he was using a Fluke 87 with Min Max feature which is a really good way to do it if you have Min Max on your meter. The way I understand the Min Max spec for the 87 is that it will catch any min or max that has a duration of 1 millisecond or more. So that's pretty good. If you are using a different meter, it would be different. Or if you are relying on seeing what shows on the meter display in real time, you'd be limited by the update rate of the display, and that is usually only a few updates per second. (4 updates per second for the Fluke 87).

Yeah i actually have a fluke meter so it was super helpful!

BTW, ECMlink samples around 20 to 25 times per second, I think ? so that is pretty good.

I do not have DSMlink, I just posted a thread actually on standalone ecu with oem harness if you want to go check it out and see what i want to do.

The Moroso 74145 bulkhead connector looks good.
I think I remember a few people in here using a Moroso battery box for their trunk mount batteries. The Moroso 74051 shown by STM looks pretty good to me.

yeah i seen that one too, i feel like it is just too bulky for me.

Looks like it's all going ok!

Hopefully turn key with no issues Tom!

 

[We're on Boost]

Yeah i actually have a fluke meter so it was super helpful!

That's awesome. Most car guys don't want to spend the money for a Fluke meter.
I have one because in the 80's I had a friend who was an engineer at Fluke, and he got me some kind of Friends and Family discount on a Fluke 87. So that was in about 1986. And it is still as good as ever, it's a great piece of equipment. It's amazing to me that they still make the same model.
I'll take a look at your other thread.

 

[Mahreeoh17]

Found this from a member on here .Hope it helps.

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[SikhDSM]

That's awesome. Most car guys don't want to spend the money for a Fluke meter.
I have one because in the 80's I had a friend who was an engineer at Fluke, and he got me some kind of Friends and Family discount on a Fluke 87. So that was in about 1986. And it is still as good as ever, it's a great piece of equipment. It's amazing to me that they still make the same model.

Yeah, fluke is definitely worth it man. Just like any tool that you pay extra money for to make jobs easier! That’s amazing to hear, and it’s still going strong.

I'll take a look at your other thread.

For sure!

 

[SikhDSM]

All done!
Took a little longer as I deleted the EVAP canister below the battery tray and solenoids, added an extra ground from transmission to chassis, and cleaned up some wiring from the fuse box!
Overall voltage stayed consistent at 14.35v across all the nods on the distribution block while running and load test still at 11.16v so we are golden.

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[We're on Boost]

That looks good and it's really clean in there too. I like this look of components that are for function more than for style. Like that 4-bolt distribution strip.
Your voltage numbers are really good too. They are higher than mine and my battery is in the stock position. Although I do have 2 fans that run continuously - whenever the in-tank fuel pump is running.
My main electrical upgrade so far wasn't directly electrical - it was a nice custom heat shield for the alternator to make its life better.
So, on your distribution strip, you've got the wire with red heat shrink on it that is coming through the firewall I guess and running through the cabin along to floor on the passenger side to get back to the battery right? And that would be the 2 gauge wire.
Then in front of that wire, you've got 2 other wires that look pretty large gauge and where do they go? What gauge are they?
And the wire that attaches to the B post on your alternator - that is still the stock wire and it still goes directly to the fuse box just like stock? (Where there is a 100 amp alternator fuse just like stock?)
You might appreciate my 51 second YouTube Short that I put up to show some voltages on my car. Was using my $30 garage multimeter there.

 

[SikhDSM]

That looks good and it's really clean in there too. I like this look of components that are for function more than for style. Like that 4-bolt distribution strip.

I was going to put a red distribution block too, but switched it to black last minute for a more minimalistic look and aesthetic look with not much color sore to the eyes.

Your voltage numbers are really good too. They are higher than mine and my battery is in the stock position. Although I do have 2 fans that run continuously - whenever the in-tank fuel pump is running.
My main electrical upgrade so far wasn't directly electrical - it was a nice custom heat shield for the alternator to make its life better.

Why are they running continuously? Lol poor alternator maybe go with a half size rad and try to get more airflow thru the engine bay?

So, on your distribution strip, you've got the wire with red heat shrink on it that is coming through the firewall I guess and running through the cabin along to floor on the passenger side to get back to the battery right? And that would be the 2 gauge wire.

Correct.

Then in front of that wire, you've got 2 other wires that look pretty large gauge and where do they go? What gauge are they?

Those two wires came from the fuse box and are 8 gauge put i wrapped them together and split them and the end.
They were previously on the battery post as well. I am guessing that is the alternator wire and don’t know what could be the second ? Starter?

And the wire that attaches to the B post on your alternator - that is still the stock wire and it still goes directly to the fuse box just like stock? (Where there is a 100 amp alternator fuse just like stock?)

The last wire is the main positive terminal going into the harness.
No fuse ran since still connected like “stock” to the stock harness, but will be putting a 200 amp breaker in the trunk somewhere.

You might appreciate my 51 second YouTube Short that I put up to show some voltages on my car. Was using my $30 garage multimeter there.

TBH that could just voltage loss thru wire pass thru, travel, and down size of gauge?
Maybe run some new wires and add a ground.
I did add a 0 gauge ground from transmission to the frame as well.

 

[We're on Boost]

Why are they running continuously? Lol poor alternator maybe go with a half size rad and try to get more airflow thru the engine bay?

Oh, nah I'd never want a half size rad. Actually it's ok having the 2 fans running all the time like that. Believe it or not, it was Lucas English who did that. He likes simple and fool proof. I'm getting to like simple and fool proof too. I've thought about having a manual switch on the dashboard which I'd theoretically flip on a couple minutes after cold startup. But one day I'd forget. I've thought about triggering it with a thermo switch like stock, but I would want them to come on at a much lower temp than the stock trigger point, so the stock thermo switch would do me no good. And I've thought about having a timer turn them on but I don't want that either. Anything where the fans don't come on until after the engine is running is risky for me, because I won't hear the fans when the engine is running. The way it is, I get an audible check on the fans before I even hit the starter button. So I'm going to just leave it as is. My alternator has been on the car since 2018 and it has never been used without the heat shield that I made. It's a NAPA reman of the 75 amp alternator that was stock on automatic cars.

BTW my YouTube Short wasn't really a "looking for help" video. It was mostly just to show that the voltage numbers we see in ECMlink are a little low compared to some other places in the car, lower for example than on the cig lighter circuit, lower for sure than on the battery terminals, not to mention the alternator B post. People are always wondering about it. Sometimes the first thing a person notices after installing ECMlink is how low that Battery voltage number is and then they freak out thinking their alternator is dying. So I thought I'd throw in my 2 cents. It's not just them. Yes, it is voltage loss in the stock wiring that is on the small side!