Battery under the rear seat.

[decoupe]

I moved the battery into the trunk last year but regreted the loss of space so decided to put it under the rear seat.

Used an Odyssey PC 680 http://www.odysseyfactory.com/specs.htm series which was physically the largest battery that would fit in the available space. Given the performance so far I think an even smaller one would work assuming no cold weather (freezing) starts are required.

I used a two component urathane liquid mould system to form the base. Formed up three sides of the necessary outline with styrofoam and line the mould with saran wrap so it didn't bond to the car (or you'll never get it out.

Used a router to get the depth right and squared the whole thing up on a table saw. With just the web strap to prevent uplift it does not move since the base is a mirror of every bump and contour of the floor.

Throw in a battery disconnect and it's good to go. Less than half the weight of the original set up, lowered the C of G and kept me busy for part of the winter.

 

[Malc]

Neat solution
How does that urethane thingy work?
I have thought about using a rally car battery box let into the floor, made from fibreglass a la e34/e39 (7 series) but I don't know if I want to cut up the floor (and my welding)
No problems with it hitting the road over bumps etc???
Malc

 

[decoupe]

Hi Malc:

I used Por a Cast http://www.sunbeltmaterials.com/synair_product_lines.htm which is a two component molding system.

Just mix the two fluids at 1:1 and pour into what ever mold you want. It sits there for 60 secs as an amber fluid and then in 10 seconds turns opaque white, warm and solid. So exciting (long winter).

Easy to work with cutting and shaping tools and very strong, chemically inert and reasonably light. Remember the saren/ply liner or it will become one with your car.

It does not move, bump or rattle as shown.

 

[velocewest]

Very nice. I was planning to do the same with two 6v Optimas in series, but the Odyssey looks like a much cleaner setup.

 

[Malc]

Is an "Oddessy" battery one of those "gel" type ones? I don't know if they are available over here
Ta
Malc

 

[decoupe]

I messed up the link to Odyssey so here it is, Malc.

Check the site but I don't think it is a gel (though you can mount it in any orientation) - it's a "Drycell (“starved electrolyte”) no external leakage or corrosion" battery. Huh?

http://www.odysseyfactory.com/specs.htm

Link to UK suppliers:

http://www.odysseyfactory.com/uk.htm

 

[Malc]

Thanks!
Malc

 

[johnrob]

Doug,
Do you remember what gauge of wire you used to re-wire the battery? Did you use the grounding point in the engine compartment or did you move it?
John

 

[decoupe]

John:

Edit - 4 gauge is what I used. Equal to 15' heavy duty jumper cable gauge.

I'm pretty sure that it is 4 gauge braided cable but will check tonight. The grounding is to the chassis by way of a bolt connection to the drivetrain tunnel. There is also a standard grounding strap from the engine to the chassis hiding near the tranmission.

Thanks for the info on the MIG unit.

Doug

 

[johnrob]

Great - thanks.

 

[gazzol]

Nice job ! Amazing how battery technology has improved over the last few years, it's not that long ago I'd have laughed at anyone claiming that a battery of that size would start a big 6 cylinder engine. I think I'll be looking into one of those for my coupe.