Re: Battery placement

[Mark Farver <farver@mindbent.org>]

> OK, that's really what I wanted to know.  Batteries as the
> crumplezone is a good idea then?  I'm not convinced.  And I
> don't suppose the citicar had very much crumplezone to start
> with, which is where we start to get bogged down in specific
> vehicles again.

In the early days of crash testing they removed the vehicle's starting
battery to minimize the danger of acid spill.  However they discovered
that doing so noticably decreased the vehicles crashworthiness.  AFAIK
todays cars are tested with the batteries in place.

If you think about it the construction of a battery makes it a decent
energy absorber.  You have deformable metal seperators (lead plates)
surrounded by a liquid...  similar to the water barrels used as highway
barriers.

Cars are typically designed to have a rigid and strong cage around the
occupants that doesn't deform in a collision (protecting the occupants,
provided they are restrained), everything outside that cage
is expected to be energy absorbing and deformable.  Early light pickups
had poor crashworthiness becuase the cab tended to be the weakest part of
the vehicle frame.

With conversion EVs it is important to NOT alter the passenger cage.
Even the force of the batteries against their mounts could weaken that
structure...

The battery box MUST keep the batteries in place.. the box can (and
should) deform in a collision, but it should not allow the batteries to
intrude on the passenger space, and it should restrain the batteries
enough that they cannot become projectiles.  Keeping the batteries low
will also help by preventing rollovers (the most fatal) and allow you to
attach the box to the strong parts of the car (floor pans and frame
rails).

Also in most vehicle vs vehicle collisons the heavier (more massive)
vehicle usually is the safest (SUVs are an exception). Conversion
EVs tend to be heavier than their gas equivlents.

But I'm not an expert...

Mark

-- 
"The greatest dangers to liberty lurk in insidious enroachment by men of
zeal, well-meaning but without understanding."
-- Justice Louis O. Brandeis, Olmstead vs. United States