Battery Location

[DMC7492]

Hi guys this is a ETX30LA AGM battery. It fits perfectly in this location. I have used the ETX18 on bigger engines with higher compression. Is this location going to interfere with any major components or can I go ahead and weld in the mounts?
Here's a picture!
41954

[Hindsight]

I don't think it will get in the way of anything there; that is exactly where I plan on putting my oil cooler. My only concern putting it there is that it is adding weight all the way out at the end. You want all the weight as close to the center of the car as possible. But if that isn't a huge concern of yours, the battery should work just fine there.

[Buzz Skyline]

Just out of curiosity, why not in the front location? Is it too big, or are you putting something else there?

[billjr212]

I used a similar, but slightly smaller battery in the same place. Just tuck it in as far forward and towards the transmission as possible (to Hindsight's point above), and it should fit with no problem. You may also want to plan to spin it around 180 degrees so the battery terminals are on the outside to give yourself easier access to them and more clearance for your wiring.

[billjr212]

here is mine (it has since been painted and wiring has been cleaned up):
http://thefactoryfiveforum.com/attachment.php?attachmentid=39607&d=1426282728

[billjr212]

Just out of curiosity, why not in the front location? Is it too big, or are you putting something else there?

Buzz - I wanted mine as close to the starter as possible to reduce the wire run.

[DMC7492]

Buzz the real estate up front is spoken for.
Bill that's my plan if I can get the positive terminal forward and the outside, cable to the starter will be very short
41955

[Buzz Skyline]

Nice. I wish I'd done that. I may move things around at some point to follow suit. I'm too close to getting the thing registered to do it now, though.

[Bob_n_Cincy]

Hi guys this is a ETX30LA AGM battery. It fits perfectly in this location. I have used the ETX18 on bigger engines with higher compression. Is this location going to interfere with any major components or can I go ahead and weld in the mounts?


Don,
Your location is good.
I put mine on the passenger side of the transmission.
41956 41957
I'm thinking of moving it behind the passenger seat.

The closer the battery is to the starter, the less voltage drop you get in the wires.
You also loose a few lbs in battery cable weight.

One downside is the engine compartment heat is not good for the battery.
Bob

[Buzz Skyline]

I've never had trouble with voltage drop in the starter wires. I would imagine you'd have to have a problem with the alternator or the battery resulting in low battery voltage for that to be an issue, in which case it's best to fix the alternator or replace the battery, I think. If you want to put something else in the battery location, then it makes sense to me, otherwise I'd want to keep it at least inside the wheel base.

[David Hodgkins]

Will that location interfere with the new trunk?

:)

[Jaime]

I use 11 feet of super-flexible 3/0 wire. It cost me over a hundred bucks, but I won't have any voltage drop problems with the battery at the stock location. However, even the 4 gauge stuff that comes with the kit will only drop about 0.4 volts at 200 amps.

[flynntuna]

Will that location interfere with the new trunk?

:)

It shouldn't. But it'll make servicing harder.
http://thefactoryfiveforum.com/showthread.php?14720-San-Diego-builds-One-the-easy-way-one-the-hard-way&p=198284#post198284
Check out post #128

[Bob_n_Cincy]

I've never had trouble with voltage drop in the starter wires. I would imagine you'd have to have a problem with the alternator or the battery resulting in low battery voltage for that to be an issue, in which case it's best to fix the alternator or replace the battery, I think. If you want to put something else in the battery location, then it makes sense to me, otherwise I'd want to keep it at least inside the wheel base.

Hi Buzz,
#4 wire has about .5 volt drop per 10ft of wire at 200 amps.
#6 wire has about .8 volt drop per 10ft of wire at 200 amps.
I am not sure what size FFR supplied.

You add that to the 2 or 3 volt sag of the small battery, and it doesn't take long to get in trouble.

If your voltage at the starter gets to low, the ECU cant fire the spark and fuel injectors.

I have problems with this every time I try and use a cheap set of jumper cables.
Bob

Edit, corrected voltage drop

[Tamra]

Based on our corner balance results, if you can put it on the passenger rear it would be better. Our corner weights showed the passenger rear was about 20lbs light, without a driver, and 45lbs lighter with me in the driver seat. The front was surprisingly well balanced.

Also, if you are planning on getting the car registered, you'll need a place for your charcoal canister too.

I like the idea of the battery behind the passenger seat. We'll likely do that once we switch to a front fuel cell.

[billjr212]

Based on our corner balance results, if you can put it on the passenger rear it would be better. Our corner weights showed the passenger rear was about 20lbs light, without a driver, and 45lbs lighter with me in the driver seat. The front was surprisingly well balanced.

That is true, and I initially wanted to put it on the passenger side for that exact reason. However, that puts it right next to the heat of the CAT/exhaust. Also, I decided on driver side, since, for me at least, I almost always have a passenger riding along at the track anyway.




Also, if you are planning on getting the car registered, you'll need a place for your charcoal canister too.

Don't forget to add an * with "depending on the state" - no charcoal canister needed in Illinois.

[billjr212]

You add that to the 2 or 3 volt sag of the small battery, and it doesn't take long to get in trouble.


This exactly. In the Roadster I had before, with the battery in the trunk, I occasionally had to listen to a painfully slow first crank with the battery back in the trunk. I figured since I was going with a lightweight battery, I didn't want to tax it anymore than absolutely necessary.

[Tamra]

Don't forget to add an * with "depending on the state" - no charcoal canister needed in Illinois.

Lucky :)

[Jaime]

This exactly. In the Roadster I had before, with the battery in the trunk, I occasionally had to listen to a painfully slow first crank with the battery back in the trunk. I figured since I was going with a lightweight battery, I didn't want to tax it anymore than absolutely necessary.
I used to have a Suzuki Hayabusa that was bored out 3mm and had high compression pistons, both of which make cranking harder. Due to the design of the starter clutch, if the battery couldn't crank it over, the compression would push back and shear some of the teeth off the starter motor (the mechanism wasn't designed to be driven in reverse). After it did that a few times, I ended up with a very rigorous charging regimen and starting procedure.

[Jaime]

Lucky :)
See my thread. I used a canister about the size of a Pepsi can and my garage has been up to 90 degrees this year with no fuel smell.

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20141005_191212_zpszoyjbykt.jpg