A few people have sent me messages asking about how i do the battery install since it doesnt require any drilling, etc. Well i had this arvo off and i couldnt put together an engine i was working on as the crank needs to go back for some work, so i figured why not write this up.

Start off using 2AS (gauge) auto cable, costs between $8 and $10/m depending on where you go. You want to use cable with a current capacity of around 260amps, if you use anything less, atleast make sure you select cable with a peak current rating high enough to supply the starter when cranking (~300amps). It really is better that you dont skimp on quality here, you need high rating cable to protect against overloading which could set your car on fire, its just not worth the risk.

http://www.rd-motorsport.net/images/stories/technical/battery relocation/cable1.jpg

I didnt take pics of this, but I started off by melting a fair bit of solder into a tin crimp connector (i aim for about half full) for the terminal block end. Its quite easy to do, just use a soldering iron to drip solder inside the crimp connector, stip the insulation from your cable, then, with a blow torch and a pair of pliers, heat up the connector to turn the solder molten again. With the connector hot, simply push your cable into the connector and allow to cool. The solder will solidify and keep the cable permanently attached to the connector. All you need to do then is feed some heat shrink over the connector and shrink it with a little heat to insulate the end of the connector (or use some insulation tape if you dont have any).

You can see the connector installed on the cable here, sans heat shrink.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/connector.jpg

Start by pulling off the sil trim to get access to the carpet, it consists of push in plugs which go straight into the sil itself and hold the trim in place. If you have strong fingers you can simply start at either end and pull the trim directly up (grip from the carpet side) and they will pop out, otherwise you can use a small flat blade screw driver and lever against the plugs to pop them out. Take care and down use excessive force, try changing the position of the screwdriver if you cant seem to pop it out.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/door%20trim.jpg

If you have problems manipulating the carpet in order to get to the sil, remove the seat belt mount to make it easier. Ive taken a pic of the bolt order as i find i can never remember what order the spacers and washers go back in, nor exactly how the spring sits in order to retain the factory whip effect (designed to stop your passengers tripping over the belt when getting in the rear).

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/belt%20mount.jpg

Next remove the back seat, it comes in 2 pieces and is quite easy to remove. Take the bottom section out first, you will find 2 bolts (one either side) down at the carpet level, pop off the plastic caps and you will see them (or simply look if you are missing the caps like here). Once removed, the bottom of the seat simply pulls straight out, this will give you access to the 2 screws that hold the top of the seat steady (and also the access panel for the fuel tank if you need to get to the fuel pump and sender).

The screws are located on the underside of the seat, they screw into the metal plate between the seat and the boot (trunk). With them removed, manipulate the seat belts on either side so that they slide behind the back seat. Simply pull at the corners of the seat and slide the belt behind, it seems to work best. With that done, all you need to do is push up and pull out on the bottom of the seat. This will pop the seat off the lugs at the back and allow you to remove it. If you cant seem to pop it off, pull out a little more and hit the bottom of the seat upwards with the palm of your hand. Because the seat is wider than the space provided, once its free of the lugs, start at one side and pull the seat inwards towards the center (it flexes quite a bit), while pulling it forward towards the front. Repeat the same on the other side and you should be able to clear the top half of the seat from the car.

With the seat removed, you can remove what is essentially a door card (if it had a door), there are a couple of plugs along the seat belt end of the card which hold it in place, again like before, use your hand to pull them out or use a screwdriver for leverage. Once the plugs are free, pull the doorcard out slightly, then hit the underside in much the same fashion as the rear seat. The card has little locator lugs across the top that slide into the cavity and hold the card flush against the panel. You need to push the card upwards in order to pull it out, if you dont clear the lugs you will tear them clean out of the card which will make it difficult to reinstall.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/back%20seat.jpg

If you have ever climbed in the rear of an E21 boot (trunk) you will know there is a solid metal plate in the way which usually stops you from feeding wiring through. Now you can drill through into the back seat area, or you can use a different method that I much prefer when running wiring to the front of the car. Have you ever looked up the side of the wheel well on the rear? What you find is a large cavity space that is usually closed off by trim panels, yet is totally hollow to allow you unrestricted access to the boot (trunk).

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/rear%20wheel.jpg

With your cable, simply feed it up from the rear, through the cavity and down into the back seat. It doesnt matter where it sits for the time being, ill get to the position later.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/rear%20wheel%20cable.jpg

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/rear%20cable.jpg

With the cable through and the carpet pulled back, you should be able to see the route a few existing wiring looms take when coming from the rear seat area to the sil. I use the same sort of route which makes it easy to hide the cable and end up with a neat result where the cable isnt in any danger of being accidentally damaged/cut/pierced etc.

Follow the existing wiring along and bend all the lugs down which hold the wiring in place and pull the cable loose. You might find its a little stuck to the metal over the years as the wrap has leeched glue, but it isnt a problem. Run the cable along the sil area following the existing wiring, then feed it under the boxed section of the seat mount. The reason for doing this is the bend is quite tight (side shown) on the other side which just isnt happening given the cable thickness.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/route3.jpg

Continue to run it along the sil following the existing wiring.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/route2.jpg

With the speaker grill removed, pull back the carpeting to reveal the panel and existing wiring loom running down to the foot area. In order to remove the carpet and bend it back far enough, you might need to pull up the door seal running along the length of the sil and up the A pillar. This should allow you to pull the carpet right back and give you enough room to work on.

Continue routing your cable, but instead of following the loom that continues across the foot area, follow the other loom as it travels up the panel past the speaker area.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/route1.jpg

Keep feeding it up and it will pass under the carpet and poke itself out the top.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/cable%20top.jpg

Now (partly because i forgot to include the step in the other post :stickoutt ) is a good time to pop out the bung on the firewall which the existing loom passes through. Its just a piece of molded rubber which locates on the firewall and stops water and fumes from entering the cabin. Use a screwdriver (or pair of them, as i find its easier to pry the bung up, then move it around with the other) and pull the bung out.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/bung.jpg

With the bung removed you can get back to your cable, if you look under the top left hand side of the dash (might be different for you americans, so check if you think it is) you will see the hole where the loom passes through and the bung once sat.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/firewall.jpg

Pass the cable up through the hole and out the otherside.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/bung%20cable.jpg

Take a stanley knife (or any sharp blade) and make a cut across the bung in order to feed the cable through. You could simply remove the entire bung if you wanted, then siliconed the area around the firewall to waterproof it again, but i find its just as easy to cut it, then use a little silicone later.

With the cable passed through, now you can follow it all the way back, pushing it under the sil and bending the lugs back to hold the cable and wiring in place.

Once you have finished that, take some cable ties and a pair of side cutters. This is where i was talking about position before. Basically, rather than having the cable flopping about inside the cavity where it could get caught in the bottom where the panels meet (which would mean any damage to the panel could damage the cable), you should find a small lip to the panel which is perfect for the cable to run along. Slide the cable up along the lip, then with a couple of zip ties, tie the cable back tight against the side of the panel. BMW are great and have actually provided a few holes for this exact purpose! :redspot (no, i lie, but they are great for our purpose anyway).

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/cable%20tied.jpg

You arent quite so lucky on the other side of the wheel well though, so what i did is, up near the mount for the boot, i drilled a hole through the panel in order to give me something to tie the cable to as it followed the curve in the panel.

In this case i positioned the battery box to the left hand rear of the boot (trunk) in order that the battery can be accessed by anyone (makes it difficult when you mount it up against the rear panel of the seat) and because the owner has/had a sub setup in the rear which was in the way anyway.

You US guys dont need to bother with this as you could just use your existing battery tray (cut it out of the engine bay) or purchase another one from a parts store and screw it into place in the rear to hold the battery down. We arent so lucky here, so we require the battery to be boxed. In this case, get yourself a box and a packet of self tapping metal screws. Drill through the box and through the metal panel below it (dont worry, its hollow underneath, no fuel tanks or wiring in the way), and using the screws, fix the box firmly to the boot. I reccomend you use a good 8-10 screws in order to hold the box firmly in place (note, in the pic i have only used about 4 as i broke the drill bit when taking the pics).

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/cable%20and%20box.jpg

All you need to do is select your choice of battery terminals and fit them to the end of the cable. Like before, simply strip the cable of insulation and screw it into place. In the pic above you will get the idea (though that is a terrible terminal, but its the only one i had which would fit in order to give you a pic to look at with a terminal installed). Either cut away the carpet in order to mount the box flush with the boot (trunk) metal, or leave the carpet in, it's your choice.

I havent quite finished with the battery in the rear yet, the negative cable i purchased (dont bother marking one, just buy one, its cheaper) to run from the battery to an earth point in the rear, wasnt long enough. You can experiment with earth positions on the rear, a lot of people simply remove one nut from the top of the strut, pass the connector over it, then bolt it back down. As long as the surfaces are clean and free from dirt/grit/paint, it should be fine.

You can see the box in place below to give you a bit of an idea of its installed position. Its a compromise between easy access for the battery (especially in case of emergencies, like if you are stuck on the road), but without taking up too much boot (trunk) space.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/batterybox.jpg

Basically you can put the battery anywhere you want, just make sure you have enough cable in order to match your install location.

With the majority of the work done, you can now go back and refit all the trim panels and carpet. Everything should go back in to place perfectly just like before, the only exception might be (ive only had trouble on one car ive done it on so far) the door card. It alread has a section cut out of the bottom of it to pass wiring through, but i found it might not be large enough to pass the cable through and still get the card to line up and install correctly. Simply take a pair of side cutters and cut the board/vinyl and bend the board in order to give enough space for the cable to pass through. Dont worry, you wont see it once the seat is installed.

Carpet on side panel (near speaker) reinstalled. Shouldnt have any problem here, cable sits in a recess so you wont even see or feel it.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/carpet%201.jpg

Carpet and sil trim installed. Simply line up the plugs and, firmly, with the palm of your hand, hit the trim down against the panel to pop the plugs back in place.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/trim%20installed.jpg

Door card installed, its pretty easy to line up and get back into position, just make sure you line up the top lugs with the holes under the window, slide them through then hit down on the card at the top to push them down into position. Make sure you pass the seat belt and it's plastic guide back into the trim before doing so (it's missing on this car), then simply make sure the plugs are lined up correctly down the seat belt side of the trim and push them into place with a quick jab from the palm of your hand.

The cable, if installed correctly will totally vanish once the trim is installed.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/rear%20trim%20installed.jpg

As you can see by the corner of the seat, you wouldnt even know it was there.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/seat%20corner.jpg

All you have left to do is reinstall the seat, fitting is the reverse of removal, it can be difficult to manipulate into position, but with a bit of effort you shouldnt have a problem.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/seat%20installed.jpg

And with that, its pretty much done, all you have to do is work out what you are going to do at the engine bay side.

Personally, I stole another E21 guy's idea and used a firewall "pass through" connector as a terminal block. US guys can buy them from jegs here (http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=22603), Aussie's can get them from VPW here (http://www.vpw.com.au/productgroup.asp?CatID=0&PrdGrpID=3303) or contact your local parts supplier who will be able to order them in. Dont worry about current issues, they are brass through the connector and wont be a problem.

It makes it easy to fit, simply bolt the other end of the cable (the one with the lug fitted) to the underside of the connector.

http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/connector.jpg

All you need to do then is cut the cable supplying the fuse box with power, crimp/solder on a new ring connector, then bolt this cable and the one from the starter motor to the top of the connector. All you need to do then is to make up a bracket from a piece of metal (or pretty much anything really) to space the connector up off the body work in the engine bay (or anything else it can arc out on).

I use a strip of metal plate (3mm is good), bent with a vice into an L shape. Drill a couple of holes through the plate into the bodywork where you want to mount it, then screw it into position. With a hole saw (or a jigsaw), cut a hole through the plate and screw the connector into the bracket you made, if you look at the pic you will see it has a metal locking ring around the middle which will lock it in place. Just remove the ring, pass the connector though, then fit the locking ring and screw it down tight. Fit up your battery cable and you are right to go.

Ill have to grab some pics of this another time (and ill update it) as it was dark before i was able to get them.

List of parts if anybody is interested.


Parts

Minimum 5 metres of 2 gauge cable
Length of heatshrink (think the stuff i used was 20mm in diameter)
Solder
Tin battery lug/connector
Pass through connector
10mm (or larger) ring style crimp connector
Positive battery terminal
Negative battery cable
Self tapping metal screws
Battery box
Zip/Cable ties
Silicone

Tools used

Soldering Iron
Blow torch (gas burner can be substitued, say from cook top or bbq)
Long/Needle nosed pliers
Stanley (utility) knife
Side cutters
10mm spanner/socket
Flat blade and Phillips head screw drivers
17mm ring spanner/socket
Drill and drill bits
Bench Vice



Think thats everything needed. Anyone finds something ive used and missed, post and let me know. Ill come back later and proof read it all to fix up the mistakes iam bound to have made.

Woah! Awesome write up. Thanks :)

Woah! Awesome write up. Thanks :)

Hi.
Any shots of the battery relocation from the engine bay?
I have a JGEGS battery relocation kit, and I have not put in as of yet.

I thought you did not have to cut the cable supplying the fuse box for it to work.

Hi.
Any shots of the battery relocation from the engine bay?
I have a JGEGS battery relocation kit, and I have not put in as of yet.

I thought you did not have to cut the cable supplying the fuse box for it to work.

Like i said in the post ( i suggest you read it as i explained what you need to do), i will have to take pics of the terminal fittings, battery has gone to make way for air box.

You dont, you just need to change the connector on it. Mine have had a bolt which goes through the battery terminal, cant fit it on the through connector without changing it to a ring connector. Only two wires you need in the E21 engine bay, 1 for the starter and the other for the fuse box. Can use a normal terminal block if you can find one to suit the 2 gauge or 0 gauge cable.

Great write up! Even though I already did this; although a little different, I printed this out and added it to my DIY binder :cool

Great write up! Even though I already did this; although a little different, I printed this out and added it to my DIY binder :cool

Yes.
Great write up. I will be doing this soon, so thats why I wanted a picture of a 323i inside the engine bay.

That's an awesome write up Hatter :)

This will help many people, including myself!! :buttrock

Printed and filed in E21 DIY folder also!!

Looking forward to seeing the engine bay pics with the cable mounted.

Great writup. Here are a few alternatives I used in case anyone is interested:

Take a stanley knife (or any sharp blade) and make a cut across the bung in order to feed the cable through. You could simply remove the entire bung if you wanted, then siliconed the area around the firewall to waterproof it again, but i find its just as easy to cut it, then use a little silicone later.

You can just run the 2 gauge wire straight through the existing bung without removing it. Gently push a screwdriver through from the engine bay to pry it open while you push the wire through. No need to cut things up.

I stole another E21 guy's idea and used a firewall "pass through" connector as a terminal block.
All you need to do then is cut the cable supplying the fuse box with power, crimp/solder on a new ring connector, then bolt this cable and the one from the starter motor to the top of the connector. All you need to do then is to make up a bracket from a piece of metal (or pretty much anything really) to space the connector up off the body work in the engine bay (or anything else it can arc out on).

I ran my positive battery cable directly to the starter. I then cut the cable supplying the fuse box, used a weather tight crimp connector to extend it with 10 gage wire and ran it to the same connection on the starter motor. No junctions or terminals or brackets to make.

one thing to add: you can run the cable into the trunk without removing that side pannel, there is room if you unbolt the trim cover that covers the rear seatbelt. you can pass thru there.

one thing to add: you can run the cable into the trunk without removing that side pannel, there is room if you unbolt the trim cover that covers the rear seatbelt. you can pass thru there.

QFT
i ran all my amp wires through there ages ago..no amp now =battery cable:)
and no i wont use the old amp wires...thats just plain silly

one thing to add: you can run the cable into the trunk without removing that side pannel, there is room if you unbolt the trim cover that covers the rear seatbelt. you can pass thru there.
I ran mine through a factory slot below the cross brace along the trunk floor, so the hole is completely out of sight. IIR, no drilling required.

http://i25.photobucket.com/albums/c58/jrcook320/Turbo009.jpg

http://i25.photobucket.com/albums/c58/jrcook320/Turbo010.jpg

ah, what the heck. Here's some pics of the other stuff:
You can just run the 2 gauge wire straight through the existing bung without removing it. Gently push a screwdriver through from the engine bay to pry it open while you push the wire through.
http://i25.photobucket.com/albums/c58/jrcook320/Turbo004.jpg

http://i25.photobucket.com/albums/c58/jrcook320/Turbo006.jpg


I ran my positive battery cable directly to the starter. I then cut the cable supplying the fuse box, used a weather tight crimp connector to extend it with 10 gage wire and ran it to the same connection on the starter motor.

http://i25.photobucket.com/albums/c58/jrcook320/Turbo008.jpg

Great writup. Here are a few alternatives I used in case anyone is interested:

You can just run the 2 gauge wire straight through the existing bung without removing it. Gently push a screwdriver through from the engine bay to pry it open while you push the wire through. No need to cut things up.

I ran my positive battery cable directly to the starter. I then cut the cable supplying the fuse box, used a weather tight crimp connector to extend it with 10 gage wire and ran it to the same connection on the starter motor. No junctions or terminals or brackets to make.

Its not a good idea to leave the wire between the bung and the metal, if this is what you did, I suggest you remedy the situation right away. The area is very sharp, over time with movement, it could cut through the insulation and short out. You need to go through the bung not around it, the only way to do this is to make a hole in it, or totally remove it and fill the gap in the firewall with silicone.

Yeah, 2 problems though.

1) the M20 starter already has 4 connectors (battery, alternator, 2 x power for parts of the loom) on it already, it doesnt leave a whole lot of thread left for the nut, let alone another connector.

2) If you ever need power in the engine bay you are going to have to run another connector from the starter (which would now make it 5). With a terminal block situated in the engine bay you can hook up another cable for anything (like perhaps a stereo install) very easily.

one thing to add: you can run the cable into the trunk without removing that side pannel, there is room if you unbolt the trim cover that covers the rear seatbelt. you can pass thru there.

No offence, but you must not have read the guide very well. How do you get up the rear wheel area in order to zip tie the cable up against the inside panel if you only remove the seatbelt area?


http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/cable%20tied.jpg


As already said, its not the best solution to just leave the wiring hanging down the side of the guard, its in a spot that can be damaged easily.

Its not a good idea to leave the wire between the bung and the metal, if this is what you did, I suggest you remedy the situation right away. The area is very sharp, over time with movement, it could cut through the insulation and short out. You need to go through the bung not around it, the only way to do this is to make a hole in it, or totally remove it and fill the gap in the firewall with silicone.

Yeah, 2 problems though.

1) the M20 starter already has 4 connectors (battery, alternator, 2 x power for parts of the loom) on it already, it doesnt leave a whole lot of thread left for the nut, let alone another connector.

2) If you ever need power in the engine bay you are going to have to run another connector from the starter (which would now make it 5). With a terminal block situated in the engine bay you can hook up another cable for anything (like perhaps a stereo install) very easily.
As quoted, I said through the bung, not around it. From your pic it looks like you're running the cable around it, but I guess not? I'm also not sure why there's a need to cut or make a hole in the bung. Mine pushed right through along side the factory wiring harness (with the help from needle nose pliers to spread the bung), and I bet I could still fit another 2 gage wire through if I had to. :confused

1) There are good reasons to have a terminal, like easier jumping, a power source, etc. but it's a matter of preference. I didn't want a terminal, so I ran it straight to the starter. I'm just offering a different way to do things. Too many connectors is hardly a problem, I have a total of 3 at the starter hot terminal and have plenty of room. Combine the 2 wires on the loom to the same connector as the alternator (unless they're both 10 gage) and you're down to 3.

2) If I ever need power in the engine bay, it will be wired off of the appropiate factory circuit and will be fused off of an existing factory fuse. This includes my stereo and electric cooling fan. My amp is wired off the battery in the trunk.

No offence, but you must not have read the guide very well. How do you get up the rear wheel area in order to zip tie the cable up against the inside panel if you only remove the seatbelt area?

As already said, its not the best solution to just leave the wiring hanging down the side of the guard, its in a spot that can be damaged easily.
I understood that he ran his on the inside of that ridge under the seat back, not on the outside where it will fall down. I see no need to zip tie it there. A 2 gage wire pretty much stays put and if you get in an accident bad enough to damage it on the inside of that ridge then you've got bigger problems to worry about. Mine runs underneith the rear seat bottom and is clipped in along with the factory harness.

Again, I was just providing a few alternative ways to do a few things for anyone that reads the thread. I'm not meaning to step on any toes. When doing custom work there will always be a hundred different ways to do the same thing, it's a matter of preference on how you want to do it.

Because the bung has a middle section which is wrapped tightly around the cable. There isnt room to poke the wire through on mine, maybe the center bit of yours broke off? ill grab a better pic of what i was talking about on the weekend.

Too many connectors is a problem, there is barely any thread left on the post, i dont think it would take another couple of connections, certainly not another lug the size of the battery cable. You cant combine the 2 wires, they have already been combined from 6 wires back to 2, would need to change to a lug type of connector in order to get them all to fit inside the crimp, but then i might have problems with it actually fitting on the starter.

Yeah, but what appropriate factory circuit? if you ran a thermofan for example, or even power for an amp, there isnt an existing circuit, have to make your own.

It doesnt stay put :) It flops about because it isnt tied down in the boot, i already had a look at that the first time and the place it continued to rest was right where the lip of the guard sits. With it sitting down there, a nudge in a carpark could be enough to kink the wire, better to keep it out of the way like you have done.

And i have no problem with that, however some of the things you suggested simply wont work here, you cant really understand unless you run the same m20 and injection, you just wont have encountered the hardware before otherwise. Ill take a pic of the starter too and show you just how tight it is for space on the terminal :)

great writeup rod:)
good points from jrcook also
i think i may tackle this one on the weekend if i can get the spare time

Awesome write-up, Mad!

Hope u did up the rusty bits too..

Cheers,

Because the bung has a middle section which is wrapped tightly around the cable. There isnt room to poke the wire through on mine, maybe the center bit of yours broke off? ill grab a better pic of what i was talking about on the weekend.

Yeah, but what appropriate factory circuit? if you ran a thermofan for example, or even power for an amp, there isnt an existing circuit, have to make your own.

It doesnt stay put :) It flops about because it isnt tied down in the boot, i already had a look at that the first time and the place it continued to rest was right where the lip of the guard sits. With it sitting down there, a nudge in a carpark could be enough to kink the wire, better to keep it out of the way like you have done.
The rubber will stretch. Mine is completely intact and it worked fine.

Does the 323i not have an auxillary cooling fan? I guess a non ac car won't have one. There are still many other fused hot sources that I would pull from before I ran a new line off the battery. You don't need a terminal under the hood for amp power when the battery is in the trunk.

Where you chose to run the cable, I would agree that it is a good idea to tie it up. I was saying that if it's under the rear seat it won't go anywhere.

Awesome write-up, Mad!

Hope u did up the rusty bits too..

Cheers,

That's the owners job :D

The rubber will stretch. Mine is completely intact and it worked fine.

Does the 323i not have an auxillary cooling fan? I guess a non ac car won't have one. There are still many other fused hot sources that I would pull from before I ran a new line off the battery. You don't need a terminal under the hood for amp power when the battery is in the trunk.

Where you chose to run the cable, I would agree that it is a good idea to tie it up. I was saying that if it's under the rear seat it won't go anywhere.

Mine wont. :)

Depends on the year, there are no sources anywhere in the car which will supply a significant amount of current. The highest rated fuses already have the largest current draw placed on them, so you simply cant just tap into them.

Yeah, i thought you were replying in regards to what matte21 posted though, not yours :)

Ill get some pics of the finished job tomorrow, friday night and i just got home from a 10 hrs shift without lunch, im wasted. :embarrasm

I started my battery install today, even 0AWG fits through the bung with some cutting. Would some Selleys be good to waterproof it? I just crammed a plastic bag in there because I don't have anything else to use at the moment. The write up was a great help:)

yeah, it would be fine. any really filler is going to work.

Working on putting a motor back together at the moment, just got back from the doc's with a few stitches in my thumb (courtesy of a main bearing), so ill see if i can grab some pics of the stuff people wanted to see tomorrow.

Cool, I'l get some tomrow.

I feel your pain - I broke 2 nails whle installing my battery :(

But seriously - hope your thumb will be OK

Because the bung has a middle section which is wrapped tightly around the cable. There isnt room to poke the wire through on mine, maybe the center bit of yours broke off? ill grab a better pic of what i was talking about on the weekend.

Too many connectors is a problem, there is barely any thread left on the post, i dont think it would take another couple of connections, certainly not another lug the size of the battery cable. You cant combine the 2 wires, they have already been combined from 6 wires back to 2, would need to change to a lug type of connector in order to get them all to fit inside the crimp, but then i might have problems with it actually fitting on the starter.

Yeah, but what appropriate factory circuit? if you ran a thermofan for example, or even power for an amp, there isnt an existing circuit, have to make your own.

It doesnt stay put :) It flops about because it isnt tied down in the boot, i already had a look at that the first time and the place it continued to rest was right where the lip of the guard sits. With it sitting down there, a nudge in a carpark could be enough to kink the wire, better to keep it out of the way like you have done.

And i have no problem with that, however some of the things you suggested simply wont work here, you cant really understand unless you run the same m20 and injection, you just wont have encountered the hardware before otherwise. Ill take a pic of the starter too and show you just how tight it is for space on the terminal :)


Hi, I am getting ready to do this, and I would like to see how to do this in the engine bay. The e30 battery relocation cable that I got from a 325i is not long enough - so I got a JGEGs relocation kit and terminal for inside the engine bay.

Madhatter can you show a picture of how you wired your starter and fed power to the battery relocation kit.
I am curious how you wire that relocation connector inside the engine bay:
http://www.rd-motorsport.net/images/stories/technical/battery%20relocation/connector.jpg


Josh you install looks clean - I am going to put my battery in exactly the same place in the trunk, its just that I am reluctant to start messing with the fuse box power feed wire -if I dont have to I will not.

Hey any update. I am ready to do this,
I would like to see pics of a m20 with this done...

Hey any update. I am ready to do this,
I would like to see pics of a m20 with this done...
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i'll show you one in a couple of years:D

Joe,
The attached pix will show you the wiring. The fat red is from the batt in the trunk. The other side of the terminal has two medium sized red cables, one supplies the fuse box and the other feeds the starter. Ignore the green wire as it is the feed to the LED in the dash that indicates that the cooling fan is running. The yellow (barely visible) is the power supply to the fan circuit.

This is the jegs bulkhead fitting and the jegs cable. I also found the e30 cable too short tho I know others have used it successfully.

Bruce

Joe,
The attached pix will show you the wiring. The fat red is from the batt in the trunk. The other side of the terminal has two medium sized red cables, one supplies the fuse box and the other feeds the starter. Ignore the green wire as it is the feed to the LED in the dash that indicates that the cooling fan is running. The yellow (barely visible) is the power supply to the fan circuit.

This is the jegs bulkhead fitting and the jegs cable. I also found the e30 cable too short tho I know others have used it successfully.

Bruce
Bruce thanks.
I have cut out the battery tray and welded up the holes.
I still have on lead from the battery. Can I just tie into that rather than feeding the fuse box and the starter?

Can you post pictures of the red wires going into the fuse box and starter?

I am not sure if I need the 323i starter or a 325i one.

I won't be close enough to the Baur to get pix for a few weeks. The leads are obvious. Only one goes to the fuse box and it is part of the harness. Look for the red lead coming out of the fuse box. The starter is just as obvious.

If you need pix i'll get them later.