Got the car - an 80-something Ford Ranger pickup.  Unpowered brakes and
steering.  Standard transmission.  One of the on-line parts places
already has a conversion/motor mounting plate for this model
transmission (and lots of others). I don't think this would be
overweight, it's a small truck, nothing to it.

My commute would need about a 25 mile roundtrip range, which could
either be done at ~65 freeway speed, or about the same distance at ~35 +
stop&go.  Only a couple of hundred feet in elevation change.

I've looked at the over-the-counter drop-in components, which would
probably add up to $5K.  I might be able to do that if I spread it out,
but I'd really be interested in some DIY alternatives.

Gary



> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Byron Jeff
> Sent: Tuesday, December 04, 2007 11:57 AM
> To: piclist@mit.edu
> Subject: [OT][EE] Let's design a PICLIST electric car conversion.
> 
> All the electric car discussion of late has gotten me all 
> geeked up. It's a
> thought that I've had on and off over the years. But I don't 
> think that I
> was even prepared to pull the trigger because of the huge cost of
> conversion.
> 
> Until I met Greg Coleman's Yugo electric conversion:
> 
> http://www.austinev.org/evalbum/762
> 
> With a free doner and scrounged parts he was able to get a working
> conversion done for under $1000. This perked up my interest.
> 
> So I was thinking with all of this brainpower out on the list and with
> nearly half of the items needed for an electric car 
> conversion right in our
> wheelhouse, how feasible would it be to design a low cast electric car
> conversion? I don't know but I'm starting this thread to find out.
> 
> An electric car conversion requires seven essential elements:
> 
> 1. Donor car
> 2. Electric motor
> 3. Batteries.
> 4. Custom transmission coupling
> 5. Controller
> 6. Battery pack monitoring
> 7. Charger.
> 
> While clearly some of these items are not a custom job, I'm 
> interested in
> discussing whether or not any of the electronics items are in 
> fact doable.
> 
> So let's get started:
> 
> 1. Donor car. I'm already there. I have a 1993 Toyota Tercel 
> with a bad
> engine that consuming a ton of oil. It functions well otherwise. So a
> conversion is a logical choice. So the donor car is essentially free.
> 
> 2. The Yugo started with a 5 HP motor, and now has a 8 HP 
> motor. I found
> this 10 HP motor on Ebay:
> 
> http://cgi.ebay.com/10-HP-48V-DC-VEHICLE-ELECTRIC-MOTOR_W0QQit
emZ310003961541QQihZ021QQcategoryZ67008QQssPageNameZWDVWQQrdZ1QQcmdZView
Item
> 
> A couple of hundred bucks isn't a bad start for a motor replacement.
> 
> 3. Batteries are always a challenge. You need to manage cost, 
> weight, and
> charging. While LiPo may be great, you're talking about a 
> $20k pricetag.
> So to keep it simple and use flooded lead acid to keep the 
> costs down. One
> site I read stated that for reasonable range that batteries 
> should weigh at
> least 30% of the gross weight of the car. Since the Tercel 
> clocks in at
> about 2000 pounds, then at least 700 pounds of battery bank is needed.
> 
> 6V golf cart batteries are decently priced. However, 
> batteries like the
> Trojan T105 only clock in at 61 lbs each. So there seems to be a fit
> problem in terms of getting the right number of batteries (at 
> least 12) and
> the right voltage (48V for the given motor).
> 
> 4. Custom coupling is either a buy one or make nice at a machine shop.
> 
> 5. Controller. While not that complicated, they are costly. 
> Check out this
> page with a ton of controllers:
> 
> http://www.electricvehiclesusa.com/category_s/48.htm
> 
> Except for the high power electronics, this is in our wheelhouse.
> Fundamentally it's a PWMed high power driver that's controlled by a
> resistive input that connects to an ADC.
> 
> IIRC MOSFETs parallel OK because they self balance the load. 
> But they need
> really stiff drivers on the gate right? What about IGBTs? 
> What is the price
> point of the high power electronics as compared to the 
> controllers on the
> page above?
> 
> This page: http://evworld.com/archives/hobbyists/hartsbeat001.html
> has a discussion about rheostat-contactor controllers but no details.
> 
> 6. Battery pack monitoring. Another PIC doable task. Read the voltage
> across a shunt using ADC to get the amps for the motor. Read 
> the voltage of
> the pack to get its Depth of Discharge. I'm wondering if it's 
> possible to interface
> that to the gas gauge to get a quick idea of the DoD using existing
> instrumentation?
> 
> 7. Charging is another possible PIC project. Again the primary item is
> power electronics. It seems like a hefty isolation 
> transformer, a honking
> huge full bridge and a high powered buck converter could 
> easily charge a
> bank. And the typical bulk, absorption, trickle cycle can be 
> managed by
> either a PIC or by any number of these custom charger chips.
> 
> So I'd be interested in hearing your thoughts. Any leads on 
> an inexpensive
> battery bank would also be welcome.
> 
> BAJ
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