The 24 Hours of Lemons Forums → Lemons Tech → Battery relocation
I am a little confused about the battery rules. Do I have to move the battery from the stock location? If so, how in the hell do you do that. The car is my 94 cadillac seville.
You can leave the battery in the stock location, as long as it's held down with brackets (factory ones are fine) and the the positive terminal is covered with insulating material. Some teams relocate the battery to the trunk in order to shift the weight to the rear, but there's not much point in doing stuff like that with a Seville.
I don't want to hijack the thread, but I have a related question about battery mounting and accounting. If we relocate the battery to the driver's compartment and use a cheapo plastic battery box, then we should run an AGM battery, right? I mean it's not in the rules, but that's common sense. I do understand that batteries are part of the car's overall reliability, and running an Optima should count against the car cost, but it does also bump up against the safety issue. Or would it count against the cost because it could just as easily be mounted under the hood where an AGM isn't necessary?
I think I just answered my own question. Time to try to bring some of my old lead-acid batteries back to life.
If you relocate, I'd forget the cheapo plastic box and use serious (i.e angle iron) hold downs then cover the whole thing with a Rubbermaid tote so that if you roll, the acid will be contained and not run all over your feet....do not ask me how I know this....
If you go for a battery box the tech inspectors may ask you open the box to inspect the positive terminal. I have seen two teams that built custom battery boxes and ended up spending a good part of a half hour putting insulating tape on the positive
terminal because they thought if you couldn't see the connection it didn't matter.
Make sure either way to cover the positive terminal just to be safe.
I'm sure it depends on the particular car, but why would you want the battery in the passenger compartment? We reloated ours to the right side of the trunk for better weight distribution and to make room under the hood for our ghetto CAIS.
another semi-hijack. Supplies for the relocation(wiring, terminals, box, tie downs, etc) fall under safety right? My battery tray is pretty rusty...
I'd say not. Battery and relocating materials should count in the price of the car.
I'm sure it depends on the particular car, but why would you want the battery in the passenger compartment? We reloated ours to the right side of the trunk for better weight distribution and to make room under the hood for our ghetto CAIS.
"Better weight distribution" --> does not = putting it as far back in the trunk as you can - its better "Dynamic weight distribution" which means INSIDE the wheelbase, generally close to the vehicle centerline. On my Lex, this meant RR side in the cabin, as putting it in the trunk would be behind the rear axle centerline.
I was planning on relocating to the right rear of the passenger compartment.
I would think that it wouldn't be a safety expense because you could just as well leave it under the hood and be safe. If you're going to the trouble of moving the battery into the passenger compartment, then you're making a change for the sake of performance. So my battery will likely stay high on the right side of the firewall.
We moved our battery to just over the axle on the passenger side of the car. We used angle iron and all-thread to hold it down.
If you go for a battery box the tech inspectors may ask you open the box to inspect the positive terminal. I have seen two teams that built custom battery boxes and ended up spending a good part of a half hour putting insulating tape on the positive
terminal because they thought if you couldn't see the connection it didn't matter.
Make sure either way to cover the positive terminal just to be safe.
A half hour to put electrical tape over a terminal? They must have been getting paid by the hour 
Well the battery "box" or brackets fall under safety equipment, no matter where you mount it. if you wanna steal God's Own battery cable out of an e30 and run that to the right rear passenger compartment, the cable cost hits your budget.
When I got mine from the junk yard I told the cashier "i just have one battery cable" and made sure they didn't see the gargantuan amount of copper i was walking out of there with.
Yeah, I got 2 e30 cables for 4 bucks. It helps when you add up 12 - "I don't know what this thing is, but thought it was cool" things first.
For low-budget battery relocation, are E30 cables better than Audi 5000/100/200 batt. cables?
The E30 trunk-mount battery cable is pretty easy to remove, and cheap at junkyards, but it's super-heavy and kind of a pain to deal with. 000 gauge? BMW must have believed that any resistance to current was unacceptable. On the plus side, the cable has super-tough insulation.
It helps when you add up 12 - "I don't know what this thing is, but thought it was cool" things first.
Are we the same person?
I think we might be
The E30 trunk-mount battery cable is pretty easy to remove, and cheap at junkyards, but it's super-heavy and kind of a pain to deal with. 000 gauge? BMW must have believed that any resistance to current was unacceptable. On the plus side, the cable has super-tough insulation.
When you have a 15 ft long cable carrying 300 amps, it doesn't take much resistance to give you some serious voltage drop. For instance, the #6 cable that a lot of cars use gives you around 0.35V drop at 300A when its only 3 feet long. Now make it 15 feet long to reach the trunk and you're at 1.75V drop. That means if your battery drops to 10V during cranking, your starter is only seeing 8.25V.
Aha, the trunk mount E30 cable is heavier gage and longer than the rear seat mounted Audi cables.
Thanks Phil, good to know!
Bringing this back up to the top just to say thanks for the multiple tips on the forum about the BMW battery cables. There were some at the junkyard when I and a teammate went this weekend and we got them for $6.95 each.
Heckuva deal.
We took them from a E30 and from what I think was a 5 series, but not sure (battery under rear set and not in trunk).
I learned, though, just to cut them with a hack saw from the driver's footwell rather than trying to fish them from the engine bay and into the passenger compartment. There's a lug/union there that makes it tough to get through the hole. It then fishes out from behind the climate control console pretty easily.
The germans aren't known for their tolerance of any resistance...
We are running an optima in cab, with a beefy angle iron/all thread mount and no secondary container. Its passed tech 3times so far.
The E30 trunk-mount battery cable is pretty easy to remove, and cheap at junkyards, but it's super-heavy and kind of a pain to deal with. 000 gauge? BMW must have believed that any resistance to current was unacceptable. On the plus side, the cable has super-tough insulation.
That trunk looks a lot cleaner/shinier than our e30 was
The 24 Hours of Lemons Forums → Lemons Tech → Battery relocation