Battery Relocation

[Mazda6smtx]

I'd like to do a battery relocation on my car but I have a few questions.

Since I will only be competing in local AutoX events and the odd track day I thought it would be best to post this here.

If I do a battery relocation with a dry cell battery (http://www.odysseybatteries.com/battery/pc680series.htm) do I need to put it in a battery box, and/or do I need to have a disconnect from the outside of the car in order for it be considered safe? Or can I just mount the battery securely to the chassis put an inline fuse and call it a day?


Thanks

[Guillermo]

I suggest just getting a lightweight battery and not relocating it.
The 12lb Odyssey battery is a great high quality choice.

By the time the heavy cables, the battery box and tie downs are added to relocate the 12V battery it will add extra cost, extra work and extra weight.
Keep it simple.
I'm sure a battery box is a requirement because everyone does it that way. But I can't help you with your other question, although I'm sure it's in the rule book.

[Tashko]

Where is the battery in your car? If it's like mine and near the firewall, it's actually better to keep the battery there and close to the centre of gravity than moving it to the trunk.

I'd avoid the hassle of relocation. I un-did my relocation this summer for a couple of reasons. I saved even more weight by getting rid of the box and cables, and I believe SCCA Solo rules don't allow a battery in the "passenger compartment" which means you have to have it in the trunk which I didn't like for the reason mentioned above. I had mine nice and low where my rear seats used to be.

Thanks for reminding me to make a post that I have a battery box and cables for sale!:)

[Slowpoke]

I relocated my battery, but it wasn't for lightweighting, it was for trying to distribute my weight better. Imprezas have a very heavy LF and a very light RR. So we took a 33lb battery out of the LF, put a 26lb Optima in the RR, and it was far easier to corner balance.

Rules vary on your series. IIRC, you need a battery box for SCCA Autocross and CARS OPRC. In CASC-OR Solosprint and Solo2 you just need a "bulkhead" between the battery and the cabin. Your rear seats are an acceptable bulkhead. You're best off verifying these yourself though because it's been a couple of years since I checked.

[Guillermo]

I just finished reading the ASN Canada FIA SoloSport 2007 Lapping Regulations and it says:
The battery must be securely attached to the vehicle. If the battery is exposed directly to the passenger compartment, it must be enclosed in a securely attached and vented protective battery box, such as is commonly used in marine applications.

[Slowpoke]

Yep. Trunk isn't the passenger compartment. So, if you're going to mount it under the front passenger seat (like a lot of folks do) then it would have to be in a battery box.

[Burnsey]

Where is the battery in your car?

For the Mazda6, it's located very high up, on the driver side just behind the intake.

In terms of a good Cg, they might as well have bolted the damn thing to the roof. :D

I know that older Audi 5000's used to have the battery under the passenger seat, with two small remote posts in the engine bay if you needed a boost.

But if the cables and box and more weight anyway...I wonder if it's worth it.

Time to hit the tread mill Paul!! :p

[J.C.]

I just finished reading the ASN Canada FIA SoloSport 2007 Lapping Regulations and it says:
Quote:
"The battery must be securely attached to the vehicle. If the battery is exposed directly to the passenger compartment, it must be enclosed in a securely attached and vented protective battery box, such as is commonly used in marine applications. "


I would get a clarification on what "exposed directly to passenger compartment means". IIRC the concern with battery exposure has always been the venting of the battery. If you have a sealed battery the box serves no venting purpouse.

[Mazda6smtx]

Well the battery is an easy 25lbs lighter than stock plus as you said Steve, the battery is mounted really high. Also the Mazda6 has just about all of the weight over the front wheels and nothing on the rear.

If the rear seats are considered to be an acceptable bulkhead then I think I'm going to go ahead with this.

Does anyone else have a reason why I shouldn't? It seems to work best for weight reduction and distribution .

[Marsh]

If I was scrutineer (and I'm not) I wouldn't not consider a folding seat acceptable seperation between driver and battery.

If, however, you enclose the battery in a proper box (ie: nautical battery box), then you could put it anywhere.

[Pete@Marcor]

If I was scrutineer (and I'm not) I wouldn't not consider a folding seat acceptable seperation between driver and battery.

If, however, you enclose the battery in a proper box (ie: nautical battery box), then you could put it anywhere.

Also, one has to consider the possibility of a battery flipping over, or removing itself from the mounts you put in. A short and a large electrical fire could result. It is bad enough that you could have a flailing 25+ pound object. If it were in an insulated box, at least you would not have a fire.

[Slowpoke]

So according to the Solosport rules quoted, there's no direct exposure to the passenger compartment so trunk mount sounds fine in a sedan.

There are two safety issues...

- Battery is punctured and acid flies everywhere (rear seat will protect you from this, especially for a gel cell Optima.)
- Battery breaks out of holder on impact and flies at the back seat. (Buckle the rear seat belts when not in use, and this will provide the necessary reinforcement to prevent the battery from entering the passenger compartment.)

If I had mine to do over again... I'd buy the battery box just so I never have to worry about scrutineers giving me trouble at an event.

Edit: Good point on the fire issue. I still have the isolating cover over the positive terminal.

[Mazda6smtx]

Okay, this it need to be a box or something that will hold it in place no matter what.

I was going to make a flat mounting surface where the spare tire used to be and use this: http://www.odysseybatteries.com/accessories/pc680hd.htm

Would that be considered the same as the box? Or is the main focus to contain the battery acid?

Edit: Do you still require a box if the battery is a sealed design?

[coneman]

Even if the battery is of a sealed design I would still put in a box. If you ever carry anything in your trunk that could possibly come in contact with the terminals you stand the chance of a short circuit and/or a nasty fire. A good quality box is cheap insurance against a disaster.

[Mazda6smtx]

I guess I'll just put a cover over it with some wing nuts, I'll make it safe for sure.

I'll just look at some battery boxes and custom make a box for that battery size.

EDIT: I've looked at some on the internet and they aren't what I'm looking for, they are all big plastic things. If I make a "box" or container for the battery out of sheet metal is that acceptable?

[Guillermo]

The battery weights only 12lbs the different is weight distribution is almost insignificant. Have you calculated the optimum amount of fuel to have in your fuel tank for weight distribution? It makes much more of a difference then a dinky little 12 lb battery. I bet the thick and long cables required to go all the way to the battery in the trunk, the battery box and the mounting hardware will probably add another 4 lbs :confused:

[Burnsey]

^^^Good point about the fuel. I've wondered how low I can run without starving...so far so good on 1/2 tank.

As for the sheet metal box, the West Coast battery boxes look like they are pretty much just that, so I would think a sheetmetal box would be OK (?) Perhaps a piece of sheetmetal to fill the hole from the fold down seats to seal everything up would help - then you could remove your rear seats completely and save a few pounds as well :D

I have an idea for some fusing...may have some scrap industrial-type stuff around the shop...I'll see what I can dig up and let ya know.

[Mazda6smtx]

Steve I can tell you this about the fuel level which is a good point to bring up Guillermo. I autoX last year at the COMP event I think, with the fuel light on and when I filled up at the Sunoco at the end of Wyncroft, I filled up 65.8 liters when the tank dry is 68 liters. I don't know if I caused any damage the car seemed to respond well but boy did it feel weird. I don't recall exactly how the car was behaving but I remember being disappointed and I told myself I wouldn't run with that low fuel again.

I think it was the fact that it wouldn't oversteer, it just pushed through the corners but it wasn't like it was overbearing the front wheels it just didn't feel right.

[Slowpoke]

http://store.summitracing.com/egnsearch.asp?Ntt=battery+box&searchinresults=false&Ntk=KeywordSearch&DDS=1&N=+115

Again, stay away from conductive metals. If you're going to do it, use plastic (e.g.: Lexan) or even building something out of thin plywood would serve the purpose. This "box" doesn't have to be used to secure the battery to the chassis like the PC680 examples. You can have mounting hardware welded to the trunk and the box can go over it to prevent fluids flying around, and vent gasses via a tube.

So, the PC680 hold-down example with custom Lexan around it, venting via a tube into the fender well would comply with the goals.

Even sealed gel cells can vent explosive gasses if overheated.

[finboy]

I'd like to do a battery relocation on my car but I have a few questions.

Since I will only be competing in local AutoX events and the odd track day I thought it would be best to post this here.

If I do a battery relocation with a dry cell battery (http://www.odysseybatteries.com/battery/pc680series.htm) do I need to put it in a battery box, and/or do I need to have a disconnect from the outside of the car in order for it be considered safe? Or can I just mount the battery securely to the chassis put an inline fuse and call it a day?


Thanks

for consideration


1) is it your daily driver..
2) is it going to cost you more money..
3) is there a huge weight advantage..
4) are you a top contendor in your class
5) are there other places you could spend money / labour on
6) are you likely going to have issues with it after (or is it "set it and forget it" )
7) does it make it safer (for you and others)

If you answered yes.. is it worth the hassle?

[Mazda6smtx]

Finboy in answer to your questions:

1.Yes
2.Yes
3. -45 over the front wheels, +15lbs to the rear.
4. Finished 5th in B-mod - PITL
5. <$200 no there isn't. Most of the parts I'd like are $$$, an intake for the 6 that doesn't through a CEL is around $650.
6. In the winter I would run my Optima with the PC680
7. ???
8. It's not really much of a hassle provided I know what I'm getting into when I start. Mainly what kind and type of box will I need.


I was thinking of construction something exactly like this except the box would fit the PC680 perfectly.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=TAY%2D48101&N=700+115&autoview=sku

If something like that Taylor kit is legal for use, then I think I may go ahead and do it. After all the battery will be where my spare tire used to be, which is underneath my trunk mat, so you wouldn't even see the battery. I'm also going to be using a fused battery terminal, so that there should be any issue using a metal box.

http://www.streetwires.com/products/batteryTerminal/



On a side note, I find it kind of funny being an electrician that, have a battery box is required, yet no one bothers to check if you have one of those huge 1 farad capacitors in the car and making sure is securely connected. I think those are far more dangerous, especially if it were to get shorted out.