# My fix for the fire prone battery fuse box.



## MÄDDNESSS (Oct 18, 2010)

Let me apologize in advance. When I do things to my car, I just DO them. I'm not really THAT concerned with pics so this isn't the most comprehensive DIY. So yeah, sorry not sorry.

This all started as I was digging into the audio world with 2 sound quality friends of mine. They both have killer set ups in their cars and I wanted something fancy so they began to school me on volts, amps, Ohms, diameter an length of wire runs. When we figured out my OEM 90amp alternator wasn't sufficient for my airride or the audio set up I wanted, I got a 120amp alternator, which still isn't sufficient but I got anyways just to help until I get a fancy alternator. Afterwards we dug into fuses and circuit breakers, crimp lugs, quality and brands of -0 gauge wire discussing such things as OFC (Oxygen Free Copper) and tinned copper. Then I brought up the fact that the mk4 battery fuse panel is known to blow and catch fire.

That's when things got interesting.

Keep in mind that the 120amp alternator battery fuse box has the following fuses.
One 150A
One 110A
One 40A
Two 50As
Three 30As.
Equals 490 amps.

Both of them were absolutely blown away by how cheap VW went on this crucial component so we went shopping on the interwebz, consulted a few electrical engineers and after seeing that nobody has made a fix for this yet, we began to re-engineer the battery fuse box from the ground up.

I work on a lot of locals cars. Most anything when it comes to mk4s. Front end re-fresh, brakes, exhaust, turbos, suspension installs, gauges, frames notches, clutch jobs, engine rebuilds, timing belt jobs, big 3 wire upgrade, ect, ect. Well, recently, I replaced somebodies battery fuse box and kept his old one for what ever reason so we dissected it. We were even more amazed at how cheap VW went after we saw exactly what was suppose to be rated for, upwards to, 490amps.

We started out doing the big 3, or 4 depending on how you look at it.





































In the pics, the alternator wire was on the +battery post, I've now relocated it to the Starter.

We basically came to the conclusion that somebody at VW either doesn't know how to math electricity or just doesn't give a damn.

This little thing was suppose to carry 490amps.


















Not to mention that all of the "fuses" are stamped aluminum which is doodoo for conductivity.

You can see where mine was already warped.

We went to the interwebz and searched for better components, coming up with Bluesea being the best option. Yes, compared to other options, they are expensive. Lucky for us, not everything is ordered through them.

Being that there isn't any suitable 490 amp bus bars, we decided it best to split up the load 3 ways. One -0 gauge wire from the Alternator and 2 separate bus bars. One 250 amp and one 100 amp bus bar.

Onto the pics.








https://www.bluesea.com/products/2127/MaxiBus_250A_BusBar_-_Four_5_16in-18_Studs
https://www.bluesea.com/products/2719/MaxiBus_Insulating_Cover_for_PN_2127_and_2128









https://www.bluesea.com/products/2315/Common_100A_Mini_BusBar_-_4_Gang_with_Cover









Search around on Amazon for the other assorted lugs.
http://www.amazon.com/Ancor-252266-Marine-Electrical-2-Gauge/dp/B000NHZYOW

I didn't get a pic of the -0 gauge wire, but there are pics of it in my car later.

This tool is need to crimp the lugs.
http://www.temcoindustrialpower.com/products/Crimpers/TH0006.html#

Assorted heat shrink tubing.
http://www.amazon.com/gp/product/B00SPMD4RQ

I didn't get a pic of the fuses or the wire but you'll see pics of them.
Shop here for assorted fuses.
http://www.amazon.com/s/ref=nb_sb_n...d-keywords=manl+&rh=i:car-electronics,k:manl+

And here for wire.

http://www.ebay.com/sch/i.html?_fro...ng+cable.TRS0&_nkw=25'+welding+cable&_sacat=0

http://www.ebay.com/sch/i.html?_odk...auge+wire.TRS0&_nkw=25'+4+gauge+wire&_sacat=0


Out with the old. Remember to disconnect the ground wire off of the negative post 1st.

With the exception of the Alternator wire being replaced and rerouted, if you need instructions to get this far this mod is beyond your skill level.









I started by removing it all but its not totally necessary to do it first.

Once I started to attach MANLs (fuses) to the 250amp bus bar, I noticed I had a clearance issue.









So I spaced them with some exhaust manifold nuts to gain clearance. Yes, its more clearance than I needed but I coulnd't find little copper washers and I didn't want to use steel. The nuts had a metric thread pitch and the studs were standard so I had to tap them for the correct thread pitch. Luckily, they were close enough, I didn't have to drill it out. Just ran the tap through once or twice and it spun on and tighten down perfectly.









Next problem I ran into was the MANL fuse being too small.









So I took my dremel to it and widened it just enough.










This is when it's necessary to dismantle your OEM fuse box. The little nuts and bolts are the perfect size, well, the bolts are just a hair long but I cut them down with my dremel.

Cut all of the wires and lug them and dont forget to heat shrink them. Remember which wire went to which fuse.
Anyways, I used the nuts and bolts to fasten the lugs on the wires to the MANLs.









As you can see in the pics, I also heat shrunk the lug to the MANL too.

Now do that same for the smaller 100amp bus bar.
For power from the battery to the 100amp bus bar, I used a 4ga wire and routed it around the front of the battery to the bus bar.

End result.





































Note: See how close the stud and bolt is on the left side there ^. It is VERY close to the MANL on the bus bar. I HIGHLY recommend you isolate it. I just cleaned it up and used a few scrap pieces of heat shrink. I was going to use an RTV silicone but I don't know that it isn't conductive. I'm just finding out that it is not so I'll go cover it with that after I'm done here, unless somebody wants to prove otherwise.











And there you go. Now you have electrically sound fuses and bus bars.
If anybody has any constructive criticism, objections, pointers, ect, ect, PLEASE feel free to post. I'd like to make this easier to understand and a more common upgrade/fix as we've all seen too many of our cars and friend's cars burn down because of this.

Thanks for reading.


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## c3cars (Dec 27, 2010)

My brothers GTI had a similar issue with the Fuse Box on top of the battery. We replaced it with a stock, a little after the car was total in an accident. 
I will do this to my 20TH, since I'm looking into getting a lighter battery and I can hide the fuse box. Thanks:beer:


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## AmIdYfReAk (Nov 8, 2006)

Solid non-OE alternative man!


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## MÄDDNESSS (Oct 18, 2010)

c3cars said:


> My brothers GTI had a similar issue with the Fuse Box on top of the battery. We replaced it with a stock, a little after the car was total in an accident.
> I will do this to my 20TH, since I'm looking into getting a lighter battery and I can hide the fuse box. Thanks:beer:


Sorry to hear about your brother's misfortune. Unless he was being a moron and deserved it.

I was going to hide it but my engine bay is FAR from any kind of show quality.




AmIdYfReAk said:


> Solid non-OE alternative man!


Thanks.


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## Chris164935 (Jan 10, 2004)

What do all those wires from the fuse panel on top of the battery power?


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## MÄDDNESSS (Oct 18, 2010)

Chris164935 said:


> What do all those wires from the fuse panel on top of the battery power?


Everything except for your starter.


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## sleepy1.8t (Sep 5, 2013)

nicely done. very clean work.


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## MÄDDNESSS (Oct 18, 2010)

sleepy1.8t said:


> nicely done. very clean work.


Thanks.


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## Aronc (Jan 30, 2006)

Looks like a solid setup, nice job :thumbup:. I too eliminated that factory POS of a fusebox. My car is shaved bay and needed a nicer setup to put into my raintray after the factory one failed on me. I ended up using a cooper bussman LMI series fuse block. These are module form and you can attach a string of them together. Its been rocksolid for 1000's of miles now running many accessories such as my airride compressor, 2x Flex a lite slimfans and various other accessories. Im running a odyssey PC925 battery in the trunk aswell.


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## MÄDDNESSS (Oct 18, 2010)

in the rain tray? Look solid though.

What gauge wire do you have on each?
What kind of fuses?


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## Aronc (Jan 30, 2006)

MÄDDNESSS said:


> in the rain tray? Look solid though.
> 
> What gauge wire do you have on each?
> What kind of fuses?


There some 2 AWG. for the alt charging wire, 1/0 to the battery and i wanna say some 8 and 10 gauge stuff. 

Using AMI style fuses in the standard amperage's called out by VW. Except the one marked FCM since im running slimfans with a relay system.









Had to find somewhere and the unit fit perfect in the raintray. However im planning on a rewire soon and i'll move everything inside the cabin including the ECU.


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## MÄDDNESSS (Oct 18, 2010)

Very nice. I plan on running Derail fans after mine crap out. I may pic your brain then.


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## groggory (Apr 21, 2003)

Everything in this thread looks like a whole lot of win.

I'm going to FAQ this under electrical


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## MÄDDNESSS (Oct 18, 2010)

Thanks bud.
Just trying to light a path for the masses.


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## l88m22vette (Mar 2, 2006)

Excellent stuff, I really like the raintray idea :thumbup:


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## MÄDDNESSS (Oct 18, 2010)

l88m22vette said:


> Excellent stuff, I really like the raintray idea :thumbup:


Thanks. I may do what he did if I ever shave my bay.


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## PoorMansDub (Nov 28, 2010)

I bought a kit from Innovative Wiring that is basically the big 3. I really like this idea because I have what I consider a mediocre sound system (1600w max/800w rms) and if I'm idling, the engine actually drops and obviously lights dim even if I'm only reasonably bumping it. I do have a capacitor as well. I found some corrosion on the wires to that fuse box on the battery and was going to cut back and solder some fresh wire in but I might as well do this while I'm at it. 

Great write up man! :beer:


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## MÄDDNESSS (Oct 18, 2010)

Thank you.

However, If all you have is a mediocre sound system then a capacitor is useless. Those are only used for heavy bass drops of likes in SQ competitions.

Your drop in idle and lighting could be due to various things.

1) Bad quality wire.
The -0 gauge wire I have is rated for 350 amps across 25'. It is quality wire. If you have sub-par wire, that will reflect in lighting and other such things.

2) Obviously the battery fuse box could be part of the problem.

3) Low quality/defective components.
If you have a Chintsy Xplode amp, sub, sub box and speakers, they WILL be VERY taxing on your electrical system.

4) Wrong parts.
If whoever did it doesn't have a clue what they are are doing, they're probably didn't bother to match up the amp and sub properly. If you have a 1 Ohm D class amp, a 4 ohm sub will not perform very well with it.

You have many other possible issues before you go dive into what I've done here. Luckily for me, I was able to upgrade the fuse box before dealing with a sound system.

Do you have and know how to use a Voltmeter and Amp clamp?


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## PoorMansDub (Nov 28, 2010)

I don't know what an AMP clamp is. System is Infinity Kappa and Soundstream amp all 2ohm setup perfectly matched etc etc...the wire is OFC 2 gauge. I use the cap just so that the amp sounds cleaner in terms of response capabilities. I made the system for SQ rather than SPL. Don't get me wrong it gets loud and bumps with no distortion (proper gain and xover settings). My reasoning is that I've had bigger systems in older cars that didn't require any additional batteries or larger alternator.
Also have a brand new battery. :thumbup:

What's the AMP clamp?


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## MÄDDNESSS (Oct 18, 2010)

Capacitors are STRICTLY for SPL. You're wasting space with your set up it is also, likely, the reason for you lights dimming. A cap for SQ is doing you nothing and is VERY taxing on your Alt and battery.

Older Sounds Stream is pretty alright. The new stuff isn't as good. Infinity kappa is "meh" from what I remember. But if you have them sync'd up good, it shouldn't be a problem.

Maybe you knkw it as an Amp Meter.

Tried to copy and paste but my phone is being retarded. Just google it. It'll be the 1st this to pop up.


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## PoorMansDub (Nov 28, 2010)

Infinity gets a bad rap because people don't know how to cross them over and time them correctly so they complain about "harsh" tweets. It's a matter of preference in the end anyway. They are very clean and get very loud. The Soundstream is an older model class A/B amp 5 channel. Caps have always been up for debate. Most SPL guys just use battery banks. I have been into car audio for over a decade and have run anything from Cerwin Vega Strokers to Sony Xplod. Used to only run MB Quart when they were legit. I laugh at most people because unless you are pushing 30,000 watts these days you really aren't bumping haha. My point is I have run more powerful systems in older VWs before and not had the issue I'm having now. 

The wire upgrade did help, I can turn it up louder before it starts to affect engine and lights. On a side note, before the system, even the high speed fan coming on would dip my idle and make it jump a little.


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## MÄDDNESSS (Oct 18, 2010)

If you know what you're doing then I doubt its the cause of your strain. In which case, tI believe the factory battery fuse panel is the culprit and this upgrade would greatly benefit you.


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## MÄDDNESSS (Oct 18, 2010)

Just bumpin it.


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## Guyver96 (Jan 17, 2007)

Maddnesss how did you run the alternator cable? I'm not understanding that part. 
As is the alt cable runs to a 150 fuse then to the battery .
Did you remove the fuse all together and run the cable from alt to starter to battery? 

Stock setup is like i said alt to fuse block the thin cable to battery then there's a completly separate cable from battery to starter... 



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## All_Euro (Jul 20, 2008)

Great info :thumbup:


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## MÄDDNESSS (Oct 18, 2010)

Guyver96. Im not sure if you're just not fluent in English or if you're using google translate or you just have bad grammar but you kinda lost me.

Granted, I've been up for like 30hrs. So I'mI'm very tired. But,... I have no fuse between the Alternator and Battery. The power wire from the alternator goes to the starter then to the battery. Is that what you were asking?


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## Guyver96 (Jan 17, 2007)

Lol i have big thumbs and very small keys on my phone. Just makes it harder to type everything perfectly. Besides i am not looking for good grades ;9


But yes, that is what i was trying to figure out. You mentioned the cables and how you ran them but left out the fuse part. 


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## MÄDDNESSS (Oct 18, 2010)

I dont really care when people use shortened words and whatnot but atleast make it clear. Lol. Besides, you gotta admit, that post is pretty botched. Lol.

I realised the main purpose of the Alternator fuse was to fuse the Alternator from the battery in of a front end collision resulting in servering that big wire and the battery grounding out to the block or transmission. The likelyness of which I deem to small to be of concern. Since the Alternator wire goes to the starter 1st, I really eliminate that threat all together. Now for that same scenario to happen, the very short 1-ish foot long cable between the starter and batter would have to severed.


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## groggory (Apr 21, 2003)

MÄDDNESSS said:


> I dont really care when people use shortened words and whatnot but atleast make it clear. Lol. Besides, you gotta admit, that post is pretty botched. Lol.
> 
> I realised the main purpose of the Alternator fuse was to fuse the Alternator from the battery in of a front end collision resulting in servering that big wire and the battery grounding out to the block or transmission. The likelyness of which I deem to small to be of concern. Since the Alternator wire goes to the starter 1st, I really eliminate that threat all together. Now for that same scenario to happen, the very short 1-ish foot long cable between the starter and batter would have to severed.


As a sidenote, on the TT225 the starter and alternator are in the same circuit, unfused...

Batttery - starter - alternator


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## Guyver96 (Jan 17, 2007)

Very interesting. 

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## MÄDDNESSS (Oct 18, 2010)

groggory said:


> As a sidenote, on the TT225 the starter and alternator are in the same circuit, unfused...
> 
> Batttery - starter - alternator


News to me.

I wonder why they did that for that model.


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## groggory (Apr 21, 2003)

MÄDDNESSS said:


> News to me.
> 
> I wonder why they did that for that model.


Only thing I could think of is it's a tight engine bay and it made for simpler wiring. The TT225 engine bay is a squeeze.


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## MÄDDNESSS (Oct 18, 2010)

It is? I thought it was the same bay as a mk4.


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## groggory (Apr 21, 2003)

MÄDDNESSS said:


> It is? I thought it was the same bay as a mk4.


It kinda is, but kinda isn't. The hood profile, and nose profile seem to make it a lot tighter. I know it's easy working on my mk4 but when I worked on my friend's TT225 I had a hard time getting my hand into lots of places.


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## MÄDDNESSS (Oct 18, 2010)

Do you rememver exactly what was in the way?

Im just trying to clear this up for the masses. I'm, like, 90% sure the engine bays are identical between the TTs and the mk4s. If it was tighter fit for to get your hands in there, its not the bay is smaller. Im guessing its because of the different coolant lines or IC pipes because they have that dual SMIC setup. Unless you were working in the back of the engine then the trans would take up more space being AWD.


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## l88m22vette (Mar 2, 2006)

Here are the TT and mk4 bays, these are obviously the opposite of stock but as far as build and size you can see they are basically the same. The front end and core supports are the major differences, and cut off a lot of easy frontal access - ask me how many times I've scraped the crap out of my arm on the thin, hard plastic lip of the rad support.


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## MÄDDNESSS (Oct 18, 2010)

I wonder why the core support is closer to the engine. Bigger rad and/or AC condenser? Or is the whole core support itself just closer?


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## Guyver96 (Jan 17, 2007)

Its so beautiful....  clean,neat engine bays.
I assume it has something to do with the shape of the car. The golfs a more square front end while the tt is a bit rounder like the beetle. I think the chassis/unibody is the same tho under the body cause tt,mk4 golf and beetle can use eachothers parts with little wiggle and slight mods. Im running tt suspension,knuckles, sway bar and subframe on my beetle and mk4 golf radiator, rotors and exhaust.. 

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## jamescrawshaw3 (Mar 17, 2015)

I'm getting ready to do something very similar to this in my gli. I have a question on the manl fuses you used. Mainly what amp fuse did you use to replace the original 110amp? I can't seem to find a manl fuse in 110 amp.

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## jamescrawshaw3 (Mar 17, 2015)

Nice write up by the way. I was already looking in to doing this (I've already replaced my fuse box twice this year.)when I found your post.

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## Hedgehodge (Nov 7, 2008)

edit - dup post


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## Hedgehodge (Nov 7, 2008)

got my hands on an r32 that has it melting, used to this from my mkiv 1.8 but i want to know if anyone had any better suggestions for this setup please. Thanks  Right now I'm replacing all the wiring and using a new fuse box since I have all that, hoping to upgrade it though with more info, thank you  Mine is also 150 on my 1.8t and the r32 for alt since i upgraded alternator on 1.8t, this bar amperage just needs to exceed total as much as I can right? (exceeding 490amps, bigger is fine right?))

Confused how we got a mini bus bar with only https://www.bluesea.com/products/2315/Common_100A_Mini_BusBar_-_4_Gang_with_Cover 100amps, would we want it at least 110 since its the highest amp on that bar ? would it be bad to get 200amp bus bar? wouldnt you want all the fuses total for the bus bar? So if you left 110, 100, 50 50 wouldnt you want a busbar of 310 at least? Hell if I know




> In the pics, the alternator wire was on the +battery post, I've now relocated it to the Starter. (is this more safe?) it then goes from the starter to a 150 fuse on that other block you speak of? I know this is old so anyone please feel free to school me please.
> 
> Being that there isn't any suitable 490 amp bus bars, we decided it best to split up the load 3 ways. One -0 gauge wire from the Alternator and 2 separate bus bars. One 250 amp and one 100 amp bus bar.


*I realized you moved the alternator wire off thats why didnt get a 5 post 500amp busbar, is that a thing nowadays?*​​*How did you tie these together ? Separate cables to the battery? What gauge?*​​*Is there a better busbar nowadays vs smashing (how many/what size/is this safe) copper washers to get the clearance. Is it okay to stack 10 copper washers for the clearance or use a flat nut thats copper instead? Maybe a busbar nowadays with more room on the side to avoid road bumps / friction exposing that shrink wrap and causing bigger issues. *​​​I found this but seems a bit nuts* https://www.amazon.com/Blue-Sea-Sys...la-492948479184&ref=&adgrpid=67656252888&th=1*​​*This 8 stud may work but these are long as hell Blue Sea Power Bus Bars 5 for the 5 and the other 3 for the 3 30amp fuses (not sure how to ties those into studs)*​​

https://www.westmarine.com/buy/marinco--650a-pro-installer-heavy-duty-bus-bar-8-stud--14981708?recordNum=26

​




MARINCO 650A Pro Installer Heavy Duty Bus Bar, 5-Stud | West Marine


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​where did you connect the electrical connector that connects to the battery box for signals to the computer?​


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