B8.5 alternator charging wire questions

[mikey7182]

Hi guys,

I am in the process of installing an aftermarket stereo that will have some substantial current draw, and am having a custom high output alternator built by Singer that will put out approximately 280A. I am trying to figure out what the factory charging wire gauge is. Most are 6awg or 4awg, but I was hoping that because the factory alt is already 180A, and the battery is in the trunk, that the charging cable is 1/0, so I don't have to run a new cable.

Typically when I have done high output alternators in the past, I upgrade the charging wire (except it is under the hood and runs right to the main fuse box), and upgrade the grounds (battery to chassis and block to chassis) and everything is good to go. Are there two separate charging wires with this since the battery is not under the hood? Does it make a pit stop at the fuse box and then travel back to the trunk? Any idea where it's routed?

Thanks in advance for any help!

Mikael

[miztahsparklez]

Hi guys,

I am in the process of installing an aftermarket stereo that will have some substantial current draw, and am having a custom high output alternator built by Singer that will put out approximately 280A. I am trying to figure out what the factory charging wire gauge is. Most are 6awg or 4awg, but I was hoping that because the factory alt is already 180A, and the battery is in the trunk, that the charging cable is 1/0, so I don't have to run a new cable.

Typically when I have done high output alternators in the past, I upgrade the charging wire (except it is under the hood and runs right to the main fuse box), and upgrade the grounds (battery to chassis and block to chassis) and everything is good to go. Are there two separate charging wires with this since the battery is not under the hood? Does it make a pit stop at the fuse box and then travel back to the trunk? Any idea where it's routed?

Thanks in advance for any help!

Mikael

I was trying to source it down, but I think the alternator ends up on the "battery" post under the front cowel under the hood. I believe there's a fueseable link on there where it makes the connection.

Then there's a cable that goes all the way to the trunk. I was also thinking of doing the big 3 upgrade, but I run class d everything and my lights don't dim with 2500wrms, so I just left it.



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[mikey7182]

Thanks for the reply. I think my main concern is that I live in Phoenix, and the summers absolutely tax everything from the alt to the ac compressor. I’ll also be around 2,500w, the bulk of which will be class D, but I wasn’t sure how the factory electrical would hold up to that additional draw during 110 degree days. One idea was just adding onto my factory wiring with 1/0 instead of pulling and replacing everything. The pics of the factory charging wire that I’ve found online looks more like a harness or bundle of several cables, and most of them look to be at least 4awg but it’s hard to tell for sure. But if I leave all those intact and make an additional 1/0 run from the alt to the battery post, the post to the actual battery, and then my grounds, I think I should be ok. I mainly didn’t want to run into anything weird or out of the ordinary that might get compromised by adding new cabling (like having to scan in new battery serial numbers so the car knows to charge it appropriately, etc). I haven’t spent a ton of time working on this car myself like I have others in the past and don’t want to make an expensive mistake.

[miztahsparklez]

Thanks for the reply. I think my main concern is that I live in Phoenix, and the summers absolutely tax everything from the alt to the ac compressor. I’ll also be around 2,500w, the bulk of which will be class D, but I wasn’t sure how the factory electrical would hold up to that additional draw during 110 degree days. One idea was just adding onto my factory wiring with 1/0 instead of pulling and replacing everything. The pics of the factory charging wire that I’ve found online looks more like a harness or bundle of several cables, and most of them look to be at least 4awg but it’s hard to tell for sure. But if I leave all those intact and make an additional 1/0 run from the alt to the battery post, the post to the actual battery, and then my grounds, I think I should be ok. I mainly didn’t want to run into anything weird or out of the ordinary that might get compromised by adding new cabling (like having to scan in new battery serial numbers so the car knows to charge it appropriately, etc). I haven’t spent a ton of time working on this car myself like I have others in the past and don’t want to make an expensive mistake.

You'll be fine. Try running your stuff off the stock alternator and wiring first... If you notice dips, then run the secondary/replacement cable from alternator. I don't know if you will be able to get 1/0 to fit, but maybe 2 4ga.

I have 1/0 to my distribution blocks in the trunk from the battery and ground (I used a big bolt in the spare tire well area). The runs are so short, it does pretty well.

Also the car is fine if you unplug the battery completely. You just might have to set the clock and reset the windows for auto roll up/down again. Just be careful if you do decide to open up that bundle. I'm pretty sure the cable goes outside the car from the spare tire well.

There's a lot of space in the cable trays inside the car, but I also don't know if it's good to subject any of it to interference from the power cable. It's likely the reason why the main line from the alternator is ran outside.

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[mikey7182]

Awesome, thanks for the info. I'm already having the alt built, but I may give it a try first with the factory electrical and see how it does. Eager to finally get going on the stereo build. I did performance stuff first which is way out of character for me! It's been years since I've had a fast car. :D

[miztahsparklez]

Awesome, thanks for the info. I'm already having the alt built, but I may give it a try first with the factory electrical and see how it does. Eager to finally get going on the stereo build. I did performance stuff first which is way out of character for me! It's been years since I've had a fast car. :D

I'm probably one of the few that ripped out the entire b&o system and have taken apart the entire car for the install.


I did stereo first. Lol. It started with just a 12" in the trunk. Then I ripped out the whole thing a month later.

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[mikey7182]

What did you do up front? I know the factory doors are 8", and I'm trying to figure out how much room is in there behind the factory panel. I bought a spare stock door speaker so I have those dimensions, but not sure how much additional mounting depth there is, or if there's a possibility of going with a larger midbass, or if it's restricted by the door panel. I'm doing a pro audio/horn install and would really like to get a 10" mid in the doors. I found some that aren't that deep; it's the outer diameter I'm not sure about.

[miztahsparklez]

What did you do up front? I know the factory doors are 8", and I'm trying to figure out how much room is in there behind the factory panel. I bought a spare stock door speaker so I have those dimensions, but not sure how much additional mounting depth there is, or if there's a possibility of going with a larger midbass, or if it's restricted by the door panel. I'm doing a pro audio/horn install and would really like to get a 10" mid in the doors. I found some that aren't that deep; it's the outer diameter I'm not sure about.

I have 7's in the doors. The 8 I wanted to fit is too deep.

You need a shallow speaker there. I even have 1.5" spacers.

The factory speaker is actually only 6.5 I think, but the bracket and housing makes it 8.

A 10 won't fit at all unless you rework the panel itself.

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[mikey7182]

Bummer. The factory speaker I have is right at 8" OD until the base, where it's 9" with that flange. It's around 3" deep. I found some 8" mids that are about 3" deep and 8.4" OD, so I thought I'd just build that diameter all the way up from the flange. So you mounted 1.5" spacers directly to the door and your mids cleared? What 7" are you running?

[miztahsparklez]

Bummer. The factory speaker I have is right at 8" OD until the base, where it's 9" with that flange. It's around 3" deep. I found some 8" mids that are about 3" deep and 8.4" OD, so I thought I'd just build that diameter all the way up from the flange. So you mounted 1.5" spacers directly to the door and your mids cleared? What 7" are you running?

I forget exact model but they are seas with the nomex cone.

I offset the speaker lower to the right corner to clear the window. The window is your enemy here, otherwise, plenty of space.

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