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Discussion Starter #1
I've been unable to stomach spending the amount required to get a full
fledged EV conversion on the road this last year, so now I am considering
the idea of a hybrid system because it would certainly allow me to save a
substantial amount of money and still more or less do what I want it to do.
So here I am, trying to get an idea of what would provide reasonable
performance.

The vehicle is a 2400 lb 4WD Tercel Wagon. Integrating the motor into the
rear driveline as a direct drive unit would be dirt simple in this case due
to the configuration of the driveline. Now considering it only had 62 hp/76
lb-ft available when it was new, providing acceptable performance relative
to that seems like it wouldn't require too much. Being an 83, the car also
has a 3.73:1 rear end ratio, but a 4.11:1 is an option for it. Obviously,
there will be no weight reduction as part of the conversion.

My thought is that there are two prime instances where ICE motors waste
fuel, during low-load cruising, and while idling at stops. Additionally,
the majority of the miles on this car will be at 40 mph or less. So my
thought is that it would be very efficient to design an EV assist with just
enough torque to get rolling for a bump start at 10-15 mph, wherein the ICE
would be used for further acceleration, followed by ICE shutdown at cruising
speed up to 40 mph or so.

Realistically I don't think I will be able to get off as cheaply with the
idea of slow speed startup, but I know that the cruising mode would be
relatively inexpensive to implement with something as low as possibly a 48V
supply. Erring on the side of being a cheapskate, cruising ability would be
the priority, and range requirement on straight E-power would need not be
more than 8-10 miles to 80% DOD.

So given that, can some of you more experienced EVers throw out some system
configurations that might meet these design goals? (Again, cheap, 8-10 mile
range, cruise up to 40 mph.)

Batteries will be plug-in only and I am open to spending more on lithium
since that will better meet my needs and keep weight reasonable.

My initial impulse is that an Altrax 72V 400A controller would provide
enough energy and power to meet these goals and an ADC X91 would give me
enough torque to get rolling, but it would certainly suck some amps to do
it. Would this be a realistic combination or am I dreaming?



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Discussion Starter #2
Kip,

Kip,

Going to a hybrid will add weight to your Tercel, and eat up valuable
cargo space. Even if you did remove the motor, it is not heavy, and
will not add a lot of weight carrying ability by its removal.

For an ICE, your Tercel has a lot going for it. Do you have the 6 speed
manual, or an automatic? A quick browse of the internet shows good
mileage, good storage inside, improved wind resistance over prior
models. If your ability to carry weight is great with good brakes, you
could do ok with a hybrid, electric rear axle, and ICE front axle.

Lithium batteries would be expensive.

Consider this. Keep your Tercel running. Look for a Chevy S10 with a
bad motor. Instead of putting money into Lithium batteries, put money
into the S10 and more affordable lead acid batteries, flooded lead acid
batteries. When complete, you can take the S10 on short trips, the
Tercel on long trips, even gear up the S10 to take to the drags strip
like some on this list have done.

Just an idea. Keep us posted what you do in any case. Good luck!

Alan

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Kip C. Anderson
Sent: Tuesday, August 28, 2007 5:12 PM
To: Electric Vehicle Discussion List
Subject: [EVDL] Reasonable EV specs for a hybrid?

I've been unable to stomach spending the amount required to get a full
fledged EV conversion on the road this last year, so now I am
considering
the idea of a hybrid system because it would certainly allow me to save
a
substantial amount of money and still more or less do what I want it to
do.
So here I am, trying to get an idea of what would provide reasonable
performance.

The vehicle is a 2400 lb 4WD Tercel Wagon. Integrating the motor into
the
rear driveline as a direct drive unit would be dirt simple in this case
due
to the configuration of the driveline. Now considering it only had 62
hp/76
lb-ft available when it was new, providing acceptable performance
relative
to that seems like it wouldn't require too much. Being an 83, the car
also
has a 3.73:1 rear end ratio, but a 4.11:1 is an option for it.
Obviously,
there will be no weight reduction as part of the conversion.

My thought is that there are two prime instances where ICE motors waste
fuel, during low-load cruising, and while idling at stops.
Additionally,
the majority of the miles on this car will be at 40 mph or less. So my
thought is that it would be very efficient to design an EV assist with
just
enough torque to get rolling for a bump start at 10-15 mph, wherein the
ICE
would be used for further acceleration, followed by ICE shutdown at
cruising
speed up to 40 mph or so.

Realistically I don't think I will be able to get off as cheaply with
the
idea of slow speed startup, but I know that the cruising mode would be
relatively inexpensive to implement with something as low as possibly a
48V
supply. Erring on the side of being a cheapskate, cruising ability
would be
the priority, and range requirement on straight E-power would need not
be
more than 8-10 miles to 80% DOD.

So given that, can some of you more experienced EVers throw out some
system
configurations that might meet these design goals? (Again, cheap, 8-10
mile
range, cruise up to 40 mph.)

Batteries will be plug-in only and I am open to spending more on lithium

since that will better meet my needs and keep weight reasonable.

My initial impulse is that an Altrax 72V 400A controller would provide
enough energy and power to meet these goals and an ADC X91 would give me

enough torque to get rolling, but it would certainly suck some amps to
do
it. Would this be a realistic combination or am I dreaming?



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For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
For subscription options, see
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Discussion Starter #3
I don't think this is a very good solution. The vehicle is going to be
heaavier than either a pure ICE or pure electric, so it will operate less
efficiently in both areas.

I also don't see it saving any significant costs. You'll still need the
same size motor, and about the same size motor controller (actually you'll
need the more expensive dual shaft motor), the same cables, breakers, and
instruments. You'll still need batteries.
You'll also need custom built couplers to connect the drivelline to the
motor, and the cost of the driveline modification.

If you swap out the rear differential you'll have to swap out the front as
well.
I suppose you could solve a couple problems by disconneting the rear
wheels from the ICE permanently, if that's possible.

Overall, I'd say this will end up costing MORE than a simple conversion.

If cost is a significant problem, you might consider converting a
motorcycle or building an E-bike.

> I've been unable to stomach spending the amount required to get a full
> fledged EV conversion on the road this last year, so now I am considering
> the idea of a hybrid system because it would certainly allow me to save a
> substantial amount of money and still more or less do what I want it to
> do.
> So here I am, trying to get an idea of what would provide reasonable
> performance.
>
> The vehicle is a 2400 lb 4WD Tercel Wagon. Integrating the motor into the
> rear driveline as a direct drive unit would be dirt simple in this case
> due
> to the configuration of the driveline. Now considering it only had 62
> hp/76
> lb-ft available when it was new, providing acceptable performance relative
> to that seems like it wouldn't require too much. Being an 83, the car
> also
> has a 3.73:1 rear end ratio, but a 4.11:1 is an option for it. Obviously,
> there will be no weight reduction as part of the conversion.
>
> My thought is that there are two prime instances where ICE motors waste
> fuel, during low-load cruising, and while idling at stops. Additionally,
> the majority of the miles on this car will be at 40 mph or less. So my
> thought is that it would be very efficient to design an EV assist with
> just
> enough torque to get rolling for a bump start at 10-15 mph, wherein the
> ICE
> would be used for further acceleration, followed by ICE shutdown at
> cruising
> speed up to 40 mph or so.
>
> Realistically I don't think I will be able to get off as cheaply with the
> idea of slow speed startup, but I know that the cruising mode would be
> relatively inexpensive to implement with something as low as possibly a
> 48V
> supply. Erring on the side of being a cheapskate, cruising ability would
> be
> the priority, and range requirement on straight E-power would need not be
> more than 8-10 miles to 80% DOD.
>
> So given that, can some of you more experienced EVers throw out some
> system
> configurations that might meet these design goals? (Again, cheap, 8-10
> mile
> range, cruise up to 40 mph.)
>
> Batteries will be plug-in only and I am open to spending more on lithium
> since that will better meet my needs and keep weight reasonable.
>
> My initial impulse is that an Altrax 72V 400A controller would provide
> enough energy and power to meet these goals and an ADC X91 would give me
> enough torque to get rolling, but it would certainly suck some amps to do
> it. Would this be a realistic combination or am I dreaming?
>
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.

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Discussion Starter #4
Thanks for your thoughts on this Peter.

You've made some assumptions however which likely won't be issues:

1) I don't believe the weight of the conversion would need to be more than
400-500 lbs using lithium. While that may impose a hit of up to 20% on fuel
economy for acceleration by ICE only, the tradeoff in cruising savings is
likely to more than make up for that. Unfortunately I think the impact of
this concept will still only be comparable to improvements in other
commercially available hybrids however. So instead of 35 MPG in town,
perhaps 45 -50 mpg in town is what I would end up with. I consider that
acceptable.

2) The other issue is that the rear driveline could be completely
disconnected, as the 4WD system in this car lacks a center differential.
It's either in 4WD or it's not, though the idea of running the driveline
both in and out of the electric motor seems attractive, it's totally
impractical for me to any application I can come up with save for getting
out of a ditch. This obviously mitigates the need for dual shaft or concern
over front vs. rear differential ratios.

As far as controllers go, I suppose my question is really whether a 72V
controller that can deliver 450 amps is going to cut it, and would a higher
torque motor like the X91 be suitable, or just barely enough?

- Kip


----- Original Message -----
From: "Peter VanDerWal" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, August 28, 2007 8:44 PM
Subject: Re: [EVDL] Reasonable EV specs for a hybrid?


>I don't think this is a very good solution. The vehicle is going to be
> heaavier than either a pure ICE or pure electric, so it will operate less
> efficiently in both areas.
>
> I also don't see it saving any significant costs. You'll still need the
> same size motor, and about the same size motor controller (actually you'll
> need the more expensive dual shaft motor), the same cables, breakers, and
> instruments. You'll still need batteries.
> You'll also need custom built couplers to connect the drivelline to the
> motor, and the cost of the driveline modification.
>
> If you swap out the rear differential you'll have to swap out the front as
> well.
> I suppose you could solve a couple problems by disconneting the rear
> wheels from the ICE permanently, if that's possible.
>
> Overall, I'd say this will end up costing MORE than a simple conversion.
>
> If cost is a significant problem, you might consider converting a
> motorcycle or building an E-bike.
>
>> I've been unable to stomach spending the amount required to get a full
>> fledged EV conversion on the road this last year, so now I am considering
>> the idea of a hybrid system because it would certainly allow me to save a
>> substantial amount of money and still more or less do what I want it to
>> do.
>> So here I am, trying to get an idea of what would provide reasonable
>> performance.
>>
>> The vehicle is a 2400 lb 4WD Tercel Wagon. Integrating the motor into
>> the
>> rear driveline as a direct drive unit would be dirt simple in this case
>> due
>> to the configuration of the driveline. Now considering it only had 62
>> hp/76
>> lb-ft available when it was new, providing acceptable performance
>> relative
>> to that seems like it wouldn't require too much. Being an 83, the car
>> also
>> has a 3.73:1 rear end ratio, but a 4.11:1 is an option for it.
>> Obviously,
>> there will be no weight reduction as part of the conversion.
>>
>> My thought is that there are two prime instances where ICE motors waste
>> fuel, during low-load cruising, and while idling at stops. Additionally,
>> the majority of the miles on this car will be at 40 mph or less. So my
>> thought is that it would be very efficient to design an EV assist with
>> just
>> enough torque to get rolling for a bump start at 10-15 mph, wherein the
>> ICE
>> would be used for further acceleration, followed by ICE shutdown at
>> cruising
>> speed up to 40 mph or so.
>>
>> Realistically I don't think I will be able to get off as cheaply with the
>> idea of slow speed startup, but I know that the cruising mode would be
>> relatively inexpensive to implement with something as low as possibly a
>> 48V
>> supply. Erring on the side of being a cheapskate, cruising ability would
>> be
>> the priority, and range requirement on straight E-power would need not be
>> more than 8-10 miles to 80% DOD.
>>
>> So given that, can some of you more experienced EVers throw out some
>> system
>> configurations that might meet these design goals? (Again, cheap, 8-10
>> mile
>> range, cruise up to 40 mph.)
>>
>> Batteries will be plug-in only and I am open to spending more on lithium
>> since that will better meet my needs and keep weight reasonable.
>>
>> My initial impulse is that an Altrax 72V 400A controller would provide
>> enough energy and power to meet these goals and an ADC X91 would give me
>> enough torque to get rolling, but it would certainly suck some amps to do
>> it. Would this be a realistic combination or am I dreaming?

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Discussion Starter #5
Kip,

I'm also interested in hybrid solutions. The Tercel Wagon was my third
choice for a conversion vehicle; I actually got my second choice, a
Honda Civic Wagon. It was AWD, but I removed the rear drive train
completely.

My brother had the same idea as (I think) you did: just remove the drive
axle and put a motor on the rear diff. I vetoed this, because I
converted for reliability: I figured a hybrid would have all the
maintenance problems of an ICE, with all the range and novelty problems
of an EV. I went for a straight conversion.

I occasionally still regret having converted it to FF in the process.

For the following long response, note that I'm still getting Silent E
back on the road, so I'm not speaking from experience, the way other
people might. I'm speaking from years of reading the EVDL, with a tiny
bit of experience driving, and one experience converting.

The ADC 9" -- which I believe will be necessary to move a car of this
weight without overheating -- probably wouldn't fit without removing the
gas tank. That's okay, they make smaller gas tanks for racers and
such. But then you'd have to find a place to put the new tank, new
batteries, new controller, and new charger.

You could use an offboard charger, since you've got "infinite" ICE range.

For the all-electric conversion, I cut the floor under the rear seats
and hung a battery box underneath. That'd be good for maybe three
Optima YellowTops, with the new gas tank on one side, and the motor
extending in the middle. I insulated my box thoroughly; if you skip the
insulation, you might fit an extra battery in. In any case, some of
those batteries are likely to be hidden where they're hard to get at.

Since the engine compartment is still full of engine, you'd have to cut
out the spare tire or cargo area for your other batteries, charger, and
controller. My charger is in the tire well, so I don't have a spare,
but at least I didn't have to cut anything. The list also occasionally
discusses the loss of the spare as a problem in crashworthiness.

So, after all this, we've removed the drive shaft (probably 50 pounds or
so) and half a gas tank (negligible, really). We've added a 9" motor
(150 pounds), a charger (mostly negligible), a controller (mostly
negligible) and batteries. We've already lost 100 pounds of cargo
capacity, adding all of that weight in the rear, and we haven't even
measured the batteries yet. You need light batteries; that means
lithium. (Maybe NiCad. I'm still not so sure on that point.) And
that's expensive.

Next, an issue we haven't considered: motor RPM. The 9" doesn't go very
high before it spins itself apart (I know this from experience, as Jim
Husted will attest -- thanks again, Jim!). You'll need to pay attention
to your maximum speed so you don't overrev the motor. You can, of
course, re-gear the diff to provide either good acceleration or top
speed -- but not both. (That requires a transmission.) You mentioned
40mph, which is pretty slow; it's possible you could find a gear which
is a good compromise.

Be careful with that, though; I'm not talking about electrically pushing
the motor above 40mph. If the motor ever spins above 5000 RPM,
regardless of how it gets there, you run the risk of destroying it.
Adding a clutch could eliminate the risk, but that's a heck of a
fabrication task.

Finally, we need to consider control. If you want to keep the car
drivable by your family and friends, you'll need to figure out some way
to kick the motor (and engine) on (and off) automatically. If you're
more interested in manual control, you could try a twist-grip control
for the electric motor. (I wanted automatic drivability, but there are
no controllers I know of built for that task.) Of course, manual control
allows you to use the electric motor where it is most efficient
(acceleration, especially from zero) and the gas engine where it is most
efficient (cruising, revs at a single speed).

It's amazing how inefficient the ICE engine is at acceleration. Just by
eliminating as much acceleration as possible, I took my Honda Civic
Hatchback from 36 mpg to 43 mpg. Using the pulse-and-glide method (mild
acceleration, matched with deceleration with the engine off, then
kickstarting) I got up to 54 mpg. If I had an electric motor to do the
pulsing, I'd bet I'd get 70 mpg.

A second alternative, and the one my brother is considering for his
Suzuki Sidekick, is to keep both the engine and the motor working all
the time. This is called a "road-coupled hybrid". It makes sense, but
I don't know of anyone who's tried it yet. You wouldn't get the *best*
efficiencies, but you'd get *better* efficiencies. If you could somehow
disconnect the ICE engine -- maybe just by pushing in the clutch -- I
believe you could improve your overall efficiency significantly.

I know you said you wanted a cheapskate method. I don't think you're
going to find one, I'm afraid. The cheapest solution I can imagine is
separate, manual controls for the motor, with four to six lead-acid
batteries for the rear drive, and a small controller (like the AllTrax
you mentioned). Unfortunately, this is likely to be insufficient for
acceleration, so you'll wind up using the motor and engine at their
least efficient duties: engine for acceleration, motor for coasting.

A contactor controller would be cheap, and might allow you to
accelerate, since it doesn't have the current limits that a PWM
controller does; but most people don't like contactor controllers
because their acceleration is usually jerky (and it's easy to
underestimate your needs and build one that uses up contactors
regularly). I bet all that full-power on-off stuff is tough on the
batteries, too.

Please share your design decisions with us. I, for one, am very
interested in how things turn out for you.

Judebert




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