Battery location?

Dave L

Dave L

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Orange County, CA USA
I have a 70 2800cs, I don't expect that it matters but, it has been converted to a 3.5L with FI (L Jet). Anyway, I have always noticed that my hood sits a little bit high on one side. One day I began having some strange electrical problems. I replaced the battery and discovered that it sits high and the hood (bonnet for our overseas friends) hinge bar runs right across the top of the battery. I have the terminals protected now, but I still have a height problem. I guess todays batterys are larger that back in the 70's. I am toying with the idea of relocating the battery to the trunk (boot). Has anyone done this? Is there an acceptible kit of cables from another model that works well? any ideas are welcome.
 
Later e30's had the battery in the trunk. They have a little insulated terminal block that bolts to the firewall and makes for a nice "factory" looking install. I used one for my e12. Then you run a short heavy cable to the starter and some 8awg to the fuse box. A trip to your local welding supply store will yield nice, heavy and flexible copper wire that is perfect for the long run to the rear of the car.

The trunk isn't a bad choice -- moves the weight out of the nose, but still inside the wheels which is better for handling. Whatever you do, use an Optima gelcel battery so you will never have to worry about leaks and corrosive gasses.

My efforts have been focused on my e12 of late, but when I get back to the e9, I'm going to pick up two 6 volt Optimas, and put them on their sides under the rear seats, wired in series. This will put the weight as low as practical in the chassis, and not compromise the trunk.
 
I'm not as cool as Tony by a long shot, but I installed my battery in the trunk. Check the website for details but you can run 00 welding cable from the positive post through the cockpit, down in to the frame rail and up in to the engine compartment. Use a binding post from a late model Bimmer and you have a great power take off for starter, auxillaries, etc. I used an Optima Yellow Top and mounted it in a custom battery tray/subwoofer mount that I designed.
 
corsachili said:
I'm not as cool as Tony by a long shot
Click to expand...

Not true -- you've got an S38 in your garage, the best I can offer is an M106. And I'm completely Alfa-less, and you've got the one I really want. But... I have discovered a barn car -- on the property where I stored the e9 this winter. Looks to be a '73 or '74 GTV 2000. I say "looks to be" because it's coated with such a thick layer of dust and bird droppings, and so surrounded by junk, that I couldn't get close enough to confirm. I'm guessing based on the grill. Apparently the Bro' in law of the property owner parked it there about 15 years ago and hasn't touched it since.

Property owner -- "Yeah, I need to call him and tell him to drag that thing out of there."

Me -- "Just sit tight. I think I know someone who might be able to take it off his hands..."
 
Battery sits too high

An easier solution might be to just install an Optima battery - I suspect they are lower in height than the one causing problems. I run an Optima in my CS (as well as my other collector cars) and highly recommend them. In my area Costco has the best price on them.

As another poster wrote, if you decide to relocate your battery to the trunk, you ought to run an Optima anyhow, since they do not leak. So, your investment in an Optima (about $100) would not be wasted if you later decide to go the "trunk route".
 
Actually the S38 motor is now in a thousand pieces, none of which are in the garage! They're labeled, boxed, and stacked and in my shed, which also holds wheels for my racebike, and the entire Alfa engine, also labeled boxed and tagged.

Yes, I'm sick...............I've got it bad.

But you're still cooler than me Tony. = )
 
Next Step = Odyssey

I've put an Odyssey PC680 in my Laverda 3CL motorcycle. It's small and lots of power from its gel cell. The lady on the phone said they run one in their truck.....with a Chevy V8.

It saved about 5 lbs n my Laverda. I'll try it in my 3.0cs, as the potential weight savings is 25 lbs.

My battery is in the trunk, with welding cables run to the engine compartment, and a marine battery box.
 
Battery Relocation

I used the kit fromTEP http://www.racetep.com/rbrace.html and was happy with the results. Not particulaily attractive and eats up 30% of your trunk but works well. If you can weld (on my list of things...) you could build a better one for about $20. See TJ's site.

I like Tony's idea and may make that a winter project for decoupe and stick the TEP brace in the e21 town beater/autox project.
 
I've got the TEP brace in my e12, and I like it, but as you say -- it would be the work of an afternoon and $20 to replicate it, and the e9 trunk is dimensionally challenged as is...
 
corsachili said:
I'm not as cool as Tony by a long shot, but I installed my battery in the trunk. Check the website for details but you can run 00 welding cable from the positive post through the ****pit, down in to the frame rail and up in to the engine compartment. Use a binding post from a late model Bimmer and you have a great power take off for starter, auxillaries, etc. I used an Optima Yellow Top and mounted it in a custom battery tray/subwoofer mount that I designed.
Click to expand...

Do you have photos of your setup?
 
PO put battery in trunk

When the PO of my e9 installed a 3.5 L engine he moved the battery (Optima) to the trunk. I cannot comment on specifics or headaches encountered. What is the stock front-rear weight distribution of an e9? - BMW prides itself on being close to 50-50 for most of their cars. My e24 M6, my e30 and even my e86 M Coupe all have batteries in the back. My non-M e24 has the battery up front (whether the S38 engine is heavier or created fitment problems I cannot say).
 
gkb said:
When the PO of my e9 installed a 3.5 L engine he moved the battery (Optima) to the trunk. I cannot comment on specifics or headaches encountered. What is the stock front-rear weight distribution of an e9? - BMW prides itself on being close to 50-50 for most of their cars. .
Click to expand...

Here's a link to the weight distribution question. Still a dream.

http://www.e9coupe.com/forum/showthread.php?t=434

Doug
 
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