wtmusic's Electric Car Project / Chapter 4

A long time since Chapter 3 (April 2007). Although my commitment has not wavered my work schedule has, and unfortunately that is what is paying for the car. So between that and heavy rains here (my driveway is my workspace) I've been set back a bit. But there has been substantial progress.

One of the most challenging aspects was building the rear battery box to hold #10 56-lb. batteries safely. A figure that some use is that it should be able to withstand a forward force of 20 Gs (11,200 lbs) of force to protect the driver and passenger in front in the event of a head on collision. The two-tier box is constructed of a frame of welded steel with an inner liner of welded 1/4" polyethylene. 5 batteries rest at the level of the floor of the car and 5 have been "dropped" into the floor to improve handling. The steel welding was done by a talented local guy who I came across by chance; I decided to attempt the plastic welding myself and after many burns to the fingers have managed to sort of get the hang of it. The box is airtight to prevent fumes and hydrogen from leaking into the passenger compartment, and will also be vented underneath the car with a fan that comes on during charging.

4 batteries will be under the hood, for a total of 14 batteries and 112 volts DC. I was able to purchase "dummy" batteries (empty inside) which was extremely helpful in designing the layout and frames. The major components have been mounted but nothing has been wired yet.



L-R, top to bottom:
*Closed rear battery box, looking in from passenger side door. Front seats have been removed.
*Open rear battery box, showing two dummy batteries on top tier. Each tier will hold 5 batteries.
*Under hood. Two traction batteries at top; motor is visible underneath. At left is utility battery for car's 12-volt system (lights, wipers, etc).
*Under hood. At far right is vacuum pump for power brakes, necessary without internal combustion engine to provide vacuum. The black box is the controller, which is a MOSFET pulse-width modulator controlled by a simple resistor. Also visible in front is the main contactor, or the "on/off" switch of the car.
*Under hood looking forward, showing the other two front batteries mounted just behind the front bumper.
*The instrument panel. 3 meters -- traction pack voltage (essentially fuel level), ammeter, and 12-volt system voltage all fit fortuitously in an available space under the radio.

good for you though, I'm fascinated with your project

of 3,000 lbs, so it will need a new suspension (likely air shocks and stiffer springs). When the price comes down I'm hoping to be able to convert my "lead sled" to use Li-Ion batteries.

Giving up the engine and two passenger seats helps, so there is a little wiggle room.

Maybe the Li batteries would be more compact, as well as lighter, and you wouldn't need that? :shrug:

Besides the collision dangers, 100 lbs. sitting ahead of the front axle could make handling a little squirrelly.

I won't know how much until I try it, but there is always the option of pulling them and scaling down to 96 volts. That's one of the nice things about electric -- it's modular!

in air-conditioned comfort? And do it all powered by a solar panel? :hi:

:hi:

I'll take the heater, thank you very much!!! :rofl:

Who probably would have demanded that the AC and heat be run simultaneously, in the garage at night time, before acknowledging it was a useful vehicle.

See my journal for a long-winded response to him. :hi:

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I started playing with cars around 1966

Took an apprenticeship and got my mechanics licenses in 75 - still playin - -

A little googling got me these,

wtmusic's Electric Car Project / Chapter 1

wtmusic's Electric Car Project / Chapter 2

Couldn't find Chapter 3, but backtracked from one of the pics to find your site

http://www.mpelectriccar.org/

and your blog http://www.mpelectriccar.org/blog/

I got signatures turned off, so I dunno if it's there or not -

Anyhoo - I got some reading to do to catch up here!

I'll be back