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Putting Battery in Passenger rear compartment


mr_han_solo

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Hello,

 

I am considering relocating my battery to the rear passenger compartment of my 240 for both weight balance and because the area under my hood is rotted out from a previous leaking battery. I will repair this under-hood area, but It will be a lot easier and save me a lot of time if I dont have to reinstall the battery tray. I have done a search and I have seen a lot of people put the battery in a box in their trunk area. What I'm wanting to do is re-fabricate the passenger rear compartment for the battery, like a Corvette. Unfortunately, I haven't found anyone that has done it this way and provided pictures or problems that they ran into.

 

I know I will have to "square up the compartment" and I was worried that one of the rear axles would hit the compartment in this case. However, it looks like it will clear the axle by a lot. I was just wondering if anyone on there has done this and has pictures and would like to share their experience and insight on it with me.

 

Thanks,

 

Han

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Are you talking about the one of the two triangle sections that are behind the seats? Or directly behind the seat?  I thought the two triangle sections would be a great place to put two small batteries wired in parallel.  Would have good weight distribution and you would be able to reach the battery from either side for a jump or whatever.  

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I plan on doing it right behind the passenger seat, as low as possible. I thought about trunk area but I like my trunk space, then I thought about under the car, under the trunk area but that's too risky with the 'crumple' zones.

 

Behind the passenger eat allows for easy bracing, easy access, and better weight distribution than stock (at least, with my engine swap).

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I know what you're talking about. My 77 doesn't have them. It's the same shape but no access doors.

Really? I thought all of the S30's had them, just the later ones had them covered up by carpet. Learn something new every day.

I would be interested to see how you fit a battery into the took box. Is this a race car only or street car?

It's going to be a street able SCCA auto crosser. I want a car that I can drive around town to get the groceries and one that I can take to the track on weekends. The interior is stripped, but I will be keeping all of the turn signals and lights to keep it street able. I wanted the battery in the back for the weight distribution and because the battery tray in the front is rotted out. I'll just gut it out and weld in a patch panel for the front wheel well instead of having to acquire a new battery tray. This should make the engine compartment look cleaner and give me extra space if it's ever needed.

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I thought about it for a while when picking out batteries, mostly due to laziness, but I ended up mounting my smaller battery in the stock location.

 

I think your reasoning may be a bit flawed. The damaged area will need to be fixed by a welder, and having him weld in a little shelf or making the area flatter wouldn't make it any more expensive. In fact if you boxed that area to remove the curve I think it would be an even easier job to fix. And regarding the whole weight distribution aspect, I imagine you will be using a smaller battery? The battery is behind the front axle of the car and in front of the rear axle in the stock configuration, moving it to the tool box will still keep it behind the front axle and in front of the rear axle. Moving the battery to the trunk you move it past the rear axle and thus you exert a bit more leverage by pushing the rear down and pulling up the front. So moving it there for weight distribution won't give as big a benefit as putting as far back as possible in the trunk. Add onto that the use of a small battery which weighs 1/3 or less of the weight of a stock battery and the balance difference is fairly minute.

 

Oh, and don't forget to extend the main battery leads, which means drilling holes in your firewall, and you probably should add some jump posts towards the front of your car incase you kill the battery. You may find it difficult to drag jumper cables all the way into the cabin and wrap around your seats.

 

Worse case scenario, what happens if the battery dies and won't hold a charge? Will you be stranded until you can find another small battery? On my car I made it so that when my battery dies, and my spare is not holding a charge, I can just remove the mount and run a more standard battery to get where I'm going. If you plan on going through with this, having either a shelf in the trunk or the stock area for that possibility would be something to look into.

 

I think it is a lot of work for not too much of a benefit. But if you want to do it, it would clean up the engine bay a bit, although you will have some hefty additional wires running about.

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  • 1 month later...
  • 2 weeks later...

I ran my positive wire under the carpet along the edge of the inner sill and through the bulkhead using a through panel fitting:

 

 

 

P1000767.jpg

 

 

 

You Can see it I this photo:

 

P1010907.jpg

 

 

 

 

I need to change the red power wire to a black one:

 

DSCF1192.jpg

 

 

 

The negative was just bolted to one of the bolts used to bolt the seat in place.

 

 

It doesn't affect your fusible links, the power for these doesn't come from the battery, it comes off the starter motor. I got rid of my fusible links and replaced them with modern blade fuses tucked away behind the washer fluid bottle.

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It can, but it depends on your engine setup, spare tire setup, and other things. You just need to be aware of it. In my case (moving it to the passenger side), I'd really like the battery tray area for a catch can and some other things. The weight shift (besides decreasing the angular mass a bit), I'll worry about later.

Edited by BLOZ UP
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Sweet! Now I know the best way to run my wire. What gauge did you go with on the cables?

You want quite big wires, I used hi flex cable and I think it was 135amp.

 

 

 

 

 

I thought I read on another thread on here that moving the battery rearward hurts corner balancing of the car?

 

It can, but it depends on your engine setup, spare tire setup, and other things. You just need to be aware of it. In my case (moving it to the passenger side), I'd really like the battery tray area for a catch can and some other things. The weight shift (besides decreasing the angular mass a bit), I'll worry about later.

I can't see it effecting the balance much and I guess its like Bloz Up said, depends on your setup.

 

 

My battery and holder only weight 6.8KG so not really heavy enough to affect anything. I don't run a spare wheel as a big enough wheel to fit over my brakes won't fit in the well and I'll soon have an RB26 installed which is heavier than the L26 so if anything for me its good to move more weight backwards, plus I need the space where the battery was in the bay for a the mil spec connector for my wiring and my catch tank.

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