The Hows and Whys of Battery Relocation or How Battery Relocation Affects Corner Weight!

The Hows and Whys of Battery Relocation

By Mike Kojima 

Many suspension experts have touted the value of relocating the car’s battery in an effort to improve the weight distribution of the chassis.  Many experts claim that battery relocation is the cheapest and most efficient way to make the biggest change in chassis balance.

In setting up a car for handling it is preferable to attempt to attain a 50/50 weight distribution so that all of the wheels share the load of getting a car around a corner as equally as possible.  For drag racing, one strives to get as much weight as possible over the drive wheels to help traction.  A car’s heaviest end is often the opposite of what is ideal, such as a front wheel drive car or a front engine rear drive car.

Moroso battery relocation kit
Moroso makes this high quality battery relocation kit, however it needs a heavy duty mount as the plastic box cannot come close to containing the battery in an accident.

To try to improve the weight distribution, race car builders have resorted to things like setting the engine back in a front engine car to get more weight where it can do good, moving the location of heavy components like the radiator, oil tanks, coolers and even moving the driver.  This is all fine for the serious and heavily sponsored racer but cost and difficulty of fabrication needed to do some of these things makes them out of the question for the average enthusiast.  Well, what if you found out about a mod where you could get the same change in weight distribution as setting the engine back 5-10 inches that took very little time and money to do?  You would probably jump all over this right?

Well you can get all of the benefits of setting the engine back this amount by simply relocating the battery from the front of the engine compartment to the trunk.  This simple mod can change the weight distribution of a car from 1-2%, this is a big difference that can easily be felt by the driver in terms of less understeer and/or better traction. 

The Dog II uses several battery tricks to optimize performance.  It uses a small, lightweight Odyssey 680 dry cell battery mounted in the passenger rear side of the interior, this sheds weight, reduces polar moment of inertia, helps offset the drivers weight and improves weight distribution.

To show what a big difference simply relocating the battery can make, we took a AE86 Corolla and put it on corner scales with 200 lbs of weight to simulate a driver in the seat and moved the battery around to show what sort of difference in weight distribution simply moving the battery can make.

Password JDM carbon battery mount
Password JDM makes this very cool dry carbon mount for the Odyssey 680 was well as cool dry carbon battery boxes and relocation kits for Hondas.  We like this clean, simple and lightweight approach.

Corner scales are electronic scales used to set up the chassis of a race car with adjustable coil overs.  The spring heights of each corner are adjusted to get a 50% cross weight percentage with the driver’s weight in the seat.  When the cross weight percentage is 50% the car will have an equal balance in left and right turns regardless of the drivers offset weight in the car.

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