Weight distribution: should I relocate my battery?

I've been thinking of relocating the battery on my AE92.

Pros:

• More room for air filter, it can be closer to the front bumper and further from the hot stuff
• Shift F/R weight balance 1~2% rearwards, and every little bit helps when you're starting with 60/40 on a sub-Miata-weight car.

Cons:

• Losing much of the significant overhanging weight from the front-left corner, which is already much lighter than the front-right (engine's overhanging slightly there with all the accessories on the far right, plus this car's RHD)
• Cost, I don't think it'll be less than $100

I have coilovers with independent height adjustment and I keep the car corner-balanced. What do you think?

I'm a big believer in getting the battery out of the engine bay for all of the reasons you already mentioned. You can move the battery to a location where it can help weight distribution.

I have a book by Herb Adams on modifying second-gen F-body cars for competition.

He covers moving the battery in one part. Apparently moving the battery from the front frame end to the trunk is the equivalent of moving the engine back six inches.

Shawn

I'm more a fan of just buying a smaller battery and keeping it in the stock location. That way you don't have to add weight running heavy cables the full length of the car.

+1 to Will, with this qualifier:

A smaller lighter battery can frequently be easily moved closer to the firewall.

I have done both methods and prefer the smaller lighter battery in the engine compartment.

Rog

I'd love to get a lightweight battery but unfortunately due to some archaic laws, they're illegal for me to import unless they come with a car. You can still get them...but they're expensive and hard to find.

The battery in question is about 25lbs.

Aluminum cables and a lighter battery FTW. Firm believer in moving and lowering the battery

Can you bring in any type of battery that may be useable, but not specifically a car battery? Is it lead/ acid they have a problem with? Your friendly neighborhood exporter may be able to help. (me)

It's lithium batteries they have a problem with. They come in just fine in every modern electronic gadget and EVs and hybrid cars, but you can't bring them in by themselves.

If you are going to race this, relocating (properly) is always harder than people think.

It changes classes, adds cable weight, requires exterior shutoff (including alternator shutoff), should have fuseable links near the battery, runs heavy electric wires near the fuel tank, frequently requires vented battery box, etc. etc.

Doesn't matter if you are street driving, but it is worth understanding the entire picture if you are racing.

But yes, it is usually worth moving.

aussiesmg wrote: Aluminum cables and a lighter battery FTW. Firm believer in moving and lowering the battery

aluminum cables didn't work very well in houses.

I've moved the batteries of all my cars to the trunk (in the case of the WRX/BMWs) or behind the passenger seat (Triumph). The difference is noticeable in balance.

FWIW I use Optima Red Tops in all my cars, which are pretty heavy. I like to have a lot of cranking/accessory power on-tap, so a lightweight is a no-go for me.

iceracer wrote:

aussiesmg wrote: Aluminum cables and a lighter battery FTW. Firm believer in moving and lowering the battery

aluminum cables didn't work very well in houses.

I gave aluminum inthe Rustang, bought from scrap yard, weight is low, stiff to bend, i got 4 x 10 foot lengths for $12.

Works just fine in a car.

I ran the odyessy PC680 in my 318ti.. and will run it in my Saab 900. It is very lightweight and -not- lithium. It is an AGM (absorbed glass mat) battery

Huh I'll have to look into an AGM battery when this gel cell dies.

As for lightweight only vs. relocated...a lightweight alone wouldn't make so much room for the air filter and wouldn't do much for weight bias...but then there is the ventilation problem, higher expense and cable weight of a relocated battery (sorry I'm not ballsy enough for aluminum cables...heard too many horror stories).

I wish I could try the two and feel the handling difference to see if it's worth the price and effort difference.

iceracer wrote:

aussiesmg wrote: Aluminum cables and a lighter battery FTW. Firm believer in moving and lowering the battery

aluminum cables didn't work very well in houses.

a car isn't usually a house..

iceracer wrote:

aussiesmg wrote: Aluminum cables and a lighter battery FTW. Firm believer in moving and lowering the battery

aluminum cables didn't work very well in houses.

That's not quite right.

Aluminum wiring did not work well in branch circuits of houses, because of the necessity to join it with copper connections, copper screws on outlets, etc. The dissimilar resistance metals handle the heat differently, and compromise the connections.

Aluminum cables work just fine, and are found in the service entrance wiring of virtually every house.

Grab a battery cable set out of a BMW out of pullapart. It's designed for that specific purpose and should be cheap. Move the battery, get an Optima for a Honda it's smaller, FTW.

You have grass there, right? Go buy a small, cheap, battery for a riding lawnmower, they will crank up most <2 liter engines fine from what Ive heard and how my crappy beaters usually have batteries testing weaker than the stated ratings on a new ~350 CCA mower batt. A U1 size mower battery is about 15lbs and measures (HLW)186x197x132mm, cheap too, at least in the USA, its the cheapest lead acid battery you can buy.

Along Kenny's idea are motorcycle/powersports batteries. They are available in AGM so they can be mounted in odd positions too. The TX16L style I put in my Barracuda starts my 360 just fine. I wouldn't use the battery to sit in the car playing the radio all day, but for taking weight off the nose it's perfect.

My vote is for an electric wheel chair sealed battery(any direction up), $45 12lbs 600cca, bolted under the rear trunk of the car (mine is where the huge factory muffler used to be). A couple of big bolts, fender washers and some flat bar stock with holes fro the bolts. Get the kill switch and the a relay they make to kill the alternator power.

Good tips for alternate lightweight batteries, I know wheelchair batteries are popular in robotics but I didn't realize they had enough power to crank an engine!

I can't justify the cost of a new battery for maybe 15lbs weight savings when I have a perfectly good one though...I'd look at one of these when this one wears out.

I'll also check into what's involved in safely using aluminum cable, that would save a good bit of weight and money in a relocation.