I have done a bolt for a seatbelt before. I've also done a bolt for a hatch striker pin, just the biggest bolt you can find works. You gotta scrape the paint off underneath so it's down to bare metal to make a good connection. Use a fat ground strap too. Some people will run a separate cable all the way back up to the hood, maybe that's better I dunno.

 

I don't see how there would be any cons, every car manufacturer in the world that has ever put a battery in the trunk of one of there cars has put a jumper terminal under the hood.

 

Only 'cons' I could think regarding putting battery into the inside is if you are using standard battery. But I'm sure all of you know you need to use sealed battery inside the car.

One of the thing I thought about when I bought the Braille battery for my FD, I thought about putting it lowest point possible and put it just behind the passenger seat.

 

pics of engine bay?

 

I made a bracket that ill have to take a pic tomorrow for you guys. I put it in the hatch. I made a bracket that hold it in place and then i used a strap to keep it from moving. I just need to build an aluminum box. I put it in the hatch because I use my bins, the one with the lock i use it for my DSLR camera and iPod when I leave my windows down and the other is for fluids and also for my premix :-)

It is really down to how much use do you give your bins and if you mind giving up a bin for a battery.